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Modulated Speed Rotator User Manual

1. Figure 4 6 Enclosure Properly Mounted on All Four Pins Figure 4 6 Boitier correctement monte sur les quatre broches After the cell has been mounted and the electrode has been lowered into the cell securely mount the enclosure by hooking the enclosure to the four pins on the enclosure base see Figure 4 6 Note that the enclosure has small openings near the bottom which permit cell connections purge gas tubing and coolant to be carefully routed to the electrochemical cell from locations outside the enclosure PE 45 4 4 Cell Connections The counter electrode and the reference electrode are usually mounted in appropriate side ports on the electrochemical cell see Figure 4 7 The counter electrode is offen a simple platinum wire or carbon rod to which an alligator clip is easily affixed i NT re Figure 4 7 Connection of Counter and Reference Electrodes Always consult the manual for the potentiostat system to determine which cell cable leads should be connected to the counter and reference electrodes For newer Pine potentiostats the reference electrode cable is color coded as white and the counter electrode cable is color coded as green Many commercially available reference electrodes have a sturdy pin connector on the top end which can accept an alligator clip The cable which connects the reference electrode to the potentiostat should be of the shielded coaxial type and care should be taken fo
2. Description Part Number Precision RDE amp RROE SHOT 15 MMOD j cise tases ese tcccsussicseieseicanieectassieenicsiossiostiesigslosniniasctisael AFE6MB Gas Purged Bearing Assembly 24 25 taper for 15 mm OD RDE amp RRDE shaft ACO1TPA6 M 64 Precision RCE Shaft 15 mm OD for use with gas purged bearing assembly This shaft has a precision machined 15 0 mm outer diameter which is specially designed to mate with the 15 0 mm inner diameter of a gas purged bearing assembly This shaft has a PEEK shroud and accepts cylinder inserts which are 15 0 mm OD x 6 3 mm tall The cylinder inserts are sealed between a pair of rubber washers Description Part Number Precision RCE Shai 15 Yet a AFE9MBA Gas Purged Bearing Assembly 24 25 taper for 15 mm OD RCE shaft eens ACOITPAGM Precision Gas Purged Bearing Assembly 15 mm ID This gas purged bearing assembly fits into the 24 25 center port on an electrochemical cell A small plastic hose barb on the side of the assembly allows the space within the bearing assembly to be purged with an inert gas The main body of the assembly is made from chemically resistant PEEK polymer and the bearing Is ceramic Although the bearing is not perfectly sealed the inner diameter of the bearing 15 mm ID allows a precision machined shaft 15 mm OD to pass through the bearing assembly with a reasonably tight fit Description Part Number Gas Purged Bearing Assembl
3. alimentation de la source d alimentation avant d installer ou d enlever l arbre de I lectrode ou avant d installer ou d enlever un embout d lectrode l extr mit de l arbre 11 WARNING Do not turn on the rotator or rotate the electrode shaft if the shaft is not securely mounted in the motor coupling Inspect the shaft to be certain that it is securely mounted AVERTISSEMENT Ne mettez pas le rotateur en marche ni l arbre de l lectrode en rotation si l arbre n est pas correctement raccord au moteur Inspectez l arbre pour vous assurer qu il est bien fix WARNING Do not turn on the rotator or rotate an electrode tip if the electrode tip is not securely mounted in the electrode shaft Inspect the electrode tip to be certain that it is securely mounted AVERTISSEMENT Ne mettez pas le rotateur en marche ni un embout d lectrode en rotation si l embout d lectrode n est pas correctement fix e sur l arbre de lectrode Inspectez l embout d lectrode pour vous assurer qu elle est bien fix e WARNING Do not use or attempt to rotate an electrode shaft that has been dropped bent or otherwise physically damaged Inspect the shaft to be certain that it is not damaged AVERTISSEMENT N utilisez pas et ne tentez pas de mettre en rotation un arbre d lectrode qui est tomb a t tordu ou a t endommag physiquement d une autre mani re ou d une autre Inspectez l arbre pour
4. 87 C Note l After the motor has been removed it is a good idea to clean or EE vacuum out any debris in the brush chamber 6 5 Installing a New Motor Coupling Assembly After removing the old motor coupling assembly see above a new motor coupling assembly may be installed CAUTION A After installing a new motor it is necessary to recalibrate the rotation rate using an optical tachometer see Section 6 6 ATTENTION Apres l installation d un nouveau moteur il est n cessaire de recalibrer la vitesse de rotation l aide d un tachyme tre optique voir section 6 6 WARNING A Risk of electric shock Disconnect all power before servicing the rotator AVERTISSEMENT Risque de d charge lectrique D connectez toutes les sources d alimentation avant de proc der l entretien du rotateur WARNING Rotating shaft Entanglement hazard A Turn off the power to the rotator and disconnect the power cord from the power source before continuing with this procedure AVERTISSEMENT Arbre en rotation Danger d enchev trement teignez le rotateur et d branchez le cordon d alimentation de la source d alimentation avant de poursuivre cette proc dure Disconnect the motor control cable from the top of the motor unit Disconnect any signal cables from the brush banana jacks red and blue FINE RESEARCH INSTRUMENTATION 5 DRU 10002 REV 002 APR 201 88 Examine the new moto
5. C When performing a traceable rotation rate calibration verify j the dates on the calibration certificates for the tachometer and voltmeter and confirm that the certificates have not expired Switch off power to the rotator and disconnect the power cord With the power cord disconnected remove the cover from the control unit y peseancn wsreumentanon N DRU 10002 REV 002 APR 2015 94 While the power is switched off note the positions of the various trimmers located along the top of the main circuit board A trimmer adjustment tool or a flathead screwdriver is required to adjust these trimmers P5 P P7 While the power is switched off install the tachometer target into the motor coupling on the motor unit This target should be a metal rod with the appropriate diameter 1 4 or 6 35 mm Many tachometers require that a piece of reflective tape be attached to the end of the shaft as shown Turn the rotation rate knob fully counter clockwise This is the position which corresponds to a nearly zero rotation rate Reconnect the power cord and carefully switch on the rotator 95 WARNING Laser radiation Many optical tachometers use a laser beam as a light source Do not look directly at the laser beam Do not point the laser beam into the eye AVERTISSEMENT Rayonnement laser Un grand nombre de tachym tres optiques utilisent un faisceau laser comme source de lumi re Ne regardez p
6. Ne D w A plot of the ratio of the empirical to the apparent collection efficiency versus the reciprocal angular rotation rate should be linear The slope of such a plot can yield the rate constant if the kinematic viscosity v and the diffusion coefficient D are known 10 5 4 Comparing Two Competing Pathways Sometimes the intermediate generated by an electrochemical process can decay via two different pathways As long as one of these pathways leads to an electrochemically active chemical species that can be detected at the ring it is possible to determine which decay pathway is favored Consider the following scheme A ne X reduction of A to unstable intermediate X at disk electrode X 7 fast chemical decay of X to electrochemically inactive 7 Xy fast chemical decay of X to electrochemically active Y Y gt B n e detection of Y at ring electrode via oxidation of Y to B In the above scheme the disk electrode is poised at a potential where A is reduced to X and the cathodic limiting current observed at the disk ipisk is a measure of how much X is being generated at the disk electrode The intermediate X is unstable and as it is swept away from the disk and toward the ring it rapidly decays to either Y or Z By the time these species reach the ring all of the X has decayed away and the solution in contact with the ring contains both Y and Z The species Z is electrochemically inactive and cannot be detected by t
7. Obviously the transit time is a function of both the gap distance and the rotation rate 10 5 1 Theoretical Computation of the Collection Efficiency The theoretical collection efficiency can be computedi2 from the three principle diameters describing the RRDE geometry the disk outer diameter d the ring inner diameter d2 and the ring outer diameter d3 This somewhat tedious Computation is made easier by normalizing the ring diameters with respect to the disk diameter as follows Oop d d and Op d d Three additional quantities are defined in terms of the normalized diameters as follows O Op 1 Or O Op Oc 0 0 DRU 10002 REV 002 APR 2015 136 If a complex function G x is defined as follows 3 44 1 3 G x gt E E gt tan gt 4 4r x 1 27 42 then the theoretical collection efficiency Ntheoretica for a rotating ring disk electrode is given by the following equation N theoreticd 2 2 3 2 3 2 3 1 0 Op G 0 0 G O 4 Oo pG F Pop 10 5 2 Empirical Measurement of the Collection Efficiency Direct computation of the theoretical collection efficiency Is possible using the above relationship if the actual machined dimensions of the disk and ring are known for a particular RRDE In practice the actual RRDE dimensions may not be known due fo uncertainties in the machining process and changes in the dimensions induced by electrode polishing or temperature cycling Fo
8. Part 1 A new approach to the theory Trans Faraday Soc 62 1966 1915 1919 WJ Albery and S Bruckenstein Ring disc electrodes Part 2 Theoretical and experimental collection efficiencies Trans Faraday Soc 62 1966 1920 1931 WJ Albery S Bruckenstein and DT Napp Ring disc electrodes Part 3 Current volfage curves at the ring electrode with simultaneous currents at the disc electrode Trans Faraday Soc 62 1966 1932 1937 WJ Albery S Bruckenstein and DC Johnson Ring disc electrodes Part 4 Diffusion layer titration curves Trans Faraday Soc 62 1966 1938 1945 WJ Albery Ring disc electrodes Part 5 First order kinetic collection efficiencies at the ring electrode Trans Faraday Soc 62 1966 1946 1954 M Eisenberg CW Tobias and CR Wilke lonic Mass Transfer and Concentration Polarization at Rotating Electrodes Journal of the Electrochemical Society 101 1954 306 M Eisenberg CW Tobias and CR Wilke Chem Eng Progr Symp Ser 51 1955 1 DRU10002 REV 002 APR 20 142 20 DR Gabe Rotating Cylinder Electrode J Appl Electrochem 4 1974 91 21 DR Gabe and DJ Robinson Mass Transfer in a Rotating Cylinder Cell Laminar Flow Electrochemica Acta 17 1972 1121 22 DR Gabe and DJ Robinson Mass Transfer in a Rotating Cylinder Cell ll Turbulent Flow Electrochemica Acta 17 1972 1129 23 DR Gabe and FC Walsh The Rotating Cylinder Electrode A Review of Developme
9. subjecting the solution to ultrasonication and rotating the electrode By far the most popular and widely used hydrodynamic methods are those that involve a rotating electrode The rotating electrode geometries most amenable to mathematical modeling are the rotating disk electrode RDE the rotating ring disk electrode RRDE 2 71 and the rotating cylinder electrode RCE N8 23 Researchers take advantage of the stable steady state laminar flow conditions adjacent to an RDE or RRDE fo carefully gather information about electrode reaction kinetics 11 1724 34 In contrast the relatively chaotic and turbulent conditions adjacent fo an RCE are exploited by corrosion scientists 69 wishing FINE RESEARCH INSTRUMENTATION 3 DRU10002 REV 002 APR 201 122 to mimic flow induced pipeline corrosion conditions in the laboratory Development of the RDE and RRDE as routine analytical tools has largely been carried out by the community of academic electroanalytical chemists while the RCE has primarily been a tool used by the corrosion and electroplating industries 10 2 Half Reactions Regardless of the rotating electrode geometry being used the common theme is that an ion or molecule is being conveyed to the electrode surface and upon arrival if is either oxidized or reduced depending upon the potential applied to the rotating electrode If a sufficiently positive potential is applied fo the electrode then the mole
10. the diffusion layer is about twenty times thinner than the stagnant layer 8r 0 05 6h The first mathematical treatment of convection and diffusion towards a rotating disk electrode was given by Levich Considering the case where only the oxidized form of a molecule or ion of interest is initially present in the electrochemical cell the cathodic limiting current itc observed at a rotating disk electrode Is given by the Levich equation 2 10 iic 0 620 n F A D283 v 1 6 Co 2 in terms of the concentration Co of the oxidized form in the solution the Faraday constant F 96485 coulombs per mole the electrode area A the kinematic viscosity of the solution v the diffusion coefficient D of the oxidized form and the angular rotation rate Alternatively when the solution initially contains only the reduced form the Levich equation for the anodic limiting current ita can be written as iLa 0 620 n F A D28 v 1 6 Cp 1 2 where the concentration term Cer is for the reduced form rather than the oxidized form 10 4 1 Levich Study A Levich study is a common experiment performed using a rotating disk electrode in which a series of voltammograms is acquired over a range of different rotation rates For a simple electrochemical system where the rate of the half reaction is governed only by mass transport fo the electrode surface the overall magnitude of the voltammogram should increase with the square root of the r
11. vibrating or tilting away from the axis of rotation then turn off the rotator and remove the shaft from the rotator 41 WARNING Do not use an electrode tip which appears to wobble vibrate or tilt away from the axis of rotation while rotating Such an electrode tip is either improperly installed or physically damaged Turn off the rotator disconnect electrical power and remove the electrode tip immediately AVERTISSEMENT N utilisez pas un embout d lectrode qui semble osciller vibrer ou d vier de l axe de rotation pendant la rotation Ce embout d lectrode est soit install e de mani re incorrecte soit endommag e physiquement teignez le rotateur d connectez l alimentation lectrique et retirez l embout d lectrode imm diatement Note C A Precision Shaft Alignment Kit is available separately This l kit includes a dial indicator used to measure the runout at the end of the shaft and the end of the tip see Section 7 1 for kit part number If the shaft and tip are rotating properly along the axis of rotation then the next step is to mount the electrochemical cell that holds the test solution see Section 4 2 Figure 4 5 Properly Supported and Clamped Electrochemical Cells JENE SEARCH INSTRUMENTATION DRU10002 REV 002 APR 2015 42 4 2 Mounting the Cell All cells should be clamped to the side post and also supported from below using the cell platform For a ce
12. But it is Important to remember that the Levich equation only applies to the limiting current not to the currents along the rising portion of the sigmoid Limiting Current Levich Plot Koutecky Levich Plot 200 7 200 40000 peg KET 3600 RPM 35000 100 RPM i lt 160 30000 140 g g ici 5 25000 O O 100 5 20000 D D 804 e i gt 15000 60 E E 10000 J J 407 J 20 50007 3600RPM 0 i i 0 t 0 i 0 1000 2000 3000 4000 0 10 15 20 25 0 0 0 1 0 2 0 3 0 4 Rotation Rate RPM Rotation Rate rad s 2 Rotation Rate rad s 2 Figure 10 8 Levich Study Limiting Current versus Rotation Rate Because the Levich equation only applies to the limiting current the results trom a Levich experiment are typically presented as a simple plot of the limiting RESEARCH INSTRUMENTATION DE 133 current versus the square root of the rotation rate see Figure 10 8 center An alternate method of presenting the data from a Levich study is based on a rearrangement of the Levich equation in terms of the reciprocal current 1 ee a i 0 620 n F A D v C A plot of reciprocal current versus the reciprocal square root of the angular rotation rate see Figure 10 8 right is called a Koutecky Levich 211 plot Again for a simple and reversible half reaction with no complications the data fall along a straight line that intercepts the vertical axis at zero If the line in
13. Figure 7 2 above shows the location of the high voltage power entry and the two internal power supplies AVERTISSEMENT Risque de d charge lectrique D connectez l alimentation avant de proc der l entretien de l unit de commande La r gion ombrag e de la figure 7 2 ci dessus pr sente l emplacement de l entr e de puissance haute tension et des deux alimentations internes DRU10002 REV 002 APR 2015 114 In the rare event that it is necessary to replace one of the internal power supply units it is important to carefully identify which type of power supply is to be replaced First determine which supply 30V or 24V is to be replaced see Figure 7 2 Next carefully examine the power supply to determine which brand of power supply is to be replaced Early rotators prior to October 2014 use power supplies manufactured by Asfrodyne FranMar International or TDK Lambda Later rotators after October 2014 use power supplies manufactured by XP Power Depending upon when the rotator was manufactured choose the appropriate replacement part shown below Power Supplies for Rotators Manufactured BEFORE October 2014 Internal Power Supply 30V Internal Power Supply 24V Description Part Number Description Part Number Power Supply 30 V 60 W EE60300 DP Power Supply 24 V 60 W EE60240 DP Power Supplies for Rotators Manufactured AFTER October 2014 Internal Power Supply 30V Internal Power Supply 24V
14. Fundamentals and Applications 2nd Edition John Wiley amp Sons New York 2000 Chapter 9 DC Johnson SG Weber AM Bond RM Wightman RE Shoup and IS Krull Electroanalytical voltammetry in flowing solutions Analytica Chimica Acta 180 1986 187 250 H Gunasingham and B Fleet Wall jet electrode in continuous monitoring voltammetry Analytical Chemistry 55 1983 1409 1414 JV Macpherson and PR Unwin Hydrodynamic Modulation Voltammetry with an Oscillating Microjet Electrode Analytical Chemistry 71 1999 4642 IE Henley K Yunus and AC Fisher Volfammetry under Microfluidic Control Computer Aided Design Development and Application of Novel Microelectrochemical Reactors J of Physical Chemistry B 107 2003 3878 3884 KW Pratt and DC Johnson Vibrating wire electrodes l Literature review design and evaluation Electrochemica Acta 27 1982 1013 1021 C Hagan and LA Coury Comparison of hydrodynamic voltammetry implemented by sonication to a rotating disk electrode Analytical Chemistry 66 1994 399 405 S Bruckenstein and B Miller Unraveling reactions with rotating electrodes Acc Chem Res 10 1977 54 61 VG Levich Physicochemical Hydrodynamics Prentice Hall Upper Saddle River NJ 1962 Plots in the Diagnoses of Charge Transfer Mechanisms at Rotated Disk Electrodes Electroanalysis 14 2002 165 171 WJ Albery and ML Hitchman Ring Disc Electrodes Clarendon Press Oxford 1971 WJ Albery Ring disc electrodes
15. OD shroud 1 00 0 ceeeeeeeeeeeeeeeeeeeeeeees AFESTOSOGC Basal Plane Pyrolytic Graphite RDE tip 5 mm OD disk 15 mm OD shroudq AFESTOSOGB Edge Plane Pyrolytic Graphite RDE tip 5 mm OD disk 15 mm OD shroud AFESTOSOGE Aluminum RDE tip 5 mm OD disk 15 mm OD SAPOUG wicscssssscccacscrsmeacessvonesecssdvnsaciesuacinaccuss AFESTOSOAL Copper RDE tip 5 mm OD disk 15 mm OD SALOU AR rte AFESTOSOCU Gola RDE tip 5 mm OD disk 15 mm OD Shroud J dcscsiactsdexicriicoascahsiesierasaesialamsatcesnenieiens AFESTOSOAU Nickel RDE tip 5 mm OD disk 15 MM OD shroud ou ce cecsesseeeeesssssseeeecccccccesssseeeeeeeens AFESTOSONI Palladium RDE tip 5 mm OD disk 15 mm OD MOUV sc ccesssisveasshanianvecssnceasavscasadavenasanasees AFESTOSOPD Platinum RDE tip 5 mm OD disk 15 MM OD shroud eeeseseeeeeeeeececccceeeeeeseeeeeeenees AFESTOSOPT Silver RDE tip 5 mm OD disk 15 mm OD shroud ccs ccssasvvesscarsnesaisnccctsnyeesuceeveeistareyaveannrs AFESTOSOAG Tantalum RDE tip 5 mm OD disk 15 mm OD SHOU OD snatecccncacateieadace cecersedetcadsractcaceeennanee AFESTOSOTA Titanium RDE tip 5 mm OD disk 15 mm OD SOUSSE ES dass AFE5TOS5OTI Tungsten RDE tip 5 mm OD disk 15 mm OD NOUS RAR rente AFESTOSOW Zinc RDE tip 5 mm OD disk 15 mm OD SALOU GD iirscccstvsusc ctasssnactasnentcheeewoosssewsedsduadtecnestaredess AFESTOSOZN CAUTION A Maximum Rotation Rate 3000 RPM Do not rotate at rates higher than the maximum rotation rate A
16. OD shroudq AFE3TOSOGB Edge Plane Pyrolytic Graphite RDE tip 5 mm OD disk 12 mm OD shroud AFE3TOSOGE Aluminum RDE Tip 5 mm OD disk 12 MM OD shroud ccc ceeeceeeeeeeeeeeeeeeeseseeeeeenes AFE3TOSOAL Copper RDE tip 5 mm OD disk 12 mm OD SHOU GD se sticartecectnasendsisadacaanceramieccesendedeadstdencadecs AFE3TOS5OCU Gold RDE TO gt mm OD disk 12 MMOD AO tn areia AFE3TOSOAU Nickel RDE Tio 5 mMM OD dik 12 MAOD SNUR scctecenichecenschavenselsomnedarmacdasenaclavenienne AFESTO5SONI Palladium RDE tip 5 mm OD disk 12 MM OD shroud essssssssessssssrrrrrrrrrrrersesessssssrrrrrreeee AFE3TOSOPD Platinum RDE tip 5 mm OD disk 12 mm ODSMIOUAIS Sans AFE3TOSOPT Silver RDE tip 5 mm OD disk 12 mm OD shroud ES sieste AFE3TOSOAG Tantalum RDE tip 5 mm OD disk 12 mm OD NOUS sie tr matins AFE3TOSOTA litanium RDE tip 5 mm OD disk 12 MM OD SAOU a ccs sesesesiasssadssannsanatensosdseszessesianendesanare AFE3TOSOTI Tungsten RDE Tip 5 mm OD disk 12 MM OD shroud occ ccc ccccceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees AFE3TOSOW Zinc RDE tip 5 mm OD disk 12 MM OD SALOU ou ee eeeesseseeeeeccccccccceeeeessueeeeeeseeeeeeeeess AFESTOSOZN CAUTION A Maximum Rotation Rate 2500 RPM Do not rotate at rates higher than the maximum rotation rate ATTENTION Vitesse de rotation maximum 2500 TR MIN Ne mettez pas l appareil en rotation des vitesses sup rieures la vitesse de rotation maximum i OPERATING TEMPERATURE RANGE 1
17. Pyrolytic Graphite Disk Insert 5 mm OD x 4mm fhick AFEDOSOPO040GB Edge Plane Pyrolytic Graphite Disk Insert 5 mm OD x 4 mm fhick AFEDOSOPO40GE Aluminum Disk Insert 5 mm OD x4 Mmm NICK siens resserre AFEDOSOPO40AL Copper Disk Insert 5 mm OD x4 mMm MER dada tea AFEDOSOPO40CU Gold Disk Insert 5 mm OD x 4 MM TRICK 2er AFEDOSOPO40AU Nickel Disk Insert 5 mm OD x 4 mm thiCk ss AFEDOSOPO4ONI Palladium Disk Insert 5 mm OD x 4 mm thick Es AFEDOSOPO40PD Platinum Disk Insert 5 MM OD x 4 MM RICK eeecctettettteeteeteteeteetesseetsesteeeeees AFEDOSOPO40PT Silver Disk Insert 5 MM OD x 4 mm TICK cccccscsccssssssssvesssscsereesscessesssssssssvsesssescees AFEDOSOPO40AG Tantalum Disk Insert 5 MM OD x 4 MM THICK oo ccc cccccccscceeeeeseceeeeeeseseseeseessess AFEDOSOPO40TA itanium Disk Insert S mm OD XA mm ANICK cesscccsccsscpsscenaeptenisnepescesnegtecsnnngsessencseessanseua s AFEDOSOPO40TI Tungsten Disk Insert 5 mm OD x 4 MM TANCK csncctinnnsndctvscsadctnnnsndctvsasmddnacsndctvnamednecendetie AFEDO50P040W Zinc Disk Insert 5 mm OD x 4 mm OR an a nn AFEDOSOPO40ZN CAUTION A Maximum Rotation Rate 3000 RPM Do not rotate at rates higher than the maximum rotation rate ATTENTION Vitesse de rotation maximum 3000 TR MIN Ne mettez pas l appareil en rotation des vitesses sup rieures la vitesse de rotation maximum re OPERATING TEMPERATURE RANGE 15 C to 25 C Do not use this electrode outside the operating temperature
18. Tip Y Apply a small amount of a silicon based grease to the top of the shaft before installing the shaft into the motor coupling This helps to prevent the shaft from sticking in the coupling 35 Install the shaft by sliding it through the hole in the lower bearing assembly and into the brush chamber The shaft should be pushed as far as possible into the motor coupling so that the contact brushes are properly aligned with the electrical contact areas on the rotating electrode shaft see Figure 4 3 If the shaft is properly installed the brushes will contact metal surfaces on the shaft lf the shaft is improperly installed the brushes may contact an insulating gap on the shaft and the connection to the rotating electrode will fail Use the hex driver tool 5 64 to securely tighten both hex screws on the motor Coupling Gently tug on the shaft to make sure if is securely mounted in the motor coupling Close the clamshell doors and tighten the latch Remount the motor unit on the center post in the non inverted position CAUTION Before reconnecting the rotator power cable or the motor A control cable to the control unit be sure the control unit power switch is off and the rotation rate knob is turned to the fully counterclockwise position ATTENTION Avant de reconnecter le c ble d alimentation du rotateur ou le cable de commande du moteur l unit de commande assurez vous que l interr
19. a source of environmental noise in the measured signals from the electrochemical cell A simple banana cable with an alligator clip may be used to connect these metal objects to the earth ground Figure 4 12 Connect Metal Objects to Earth Ground on Control Box Front Panel The second important connection that is frequently but not always necessary is to connect the potentiostat to the earth ground see Figure 4 13 If such a connection is to be made if is important to understand what type of grounding connections are offered by the particular potentiostat being used consult the potentiostat documentation Most potentiostats offer either a chassis terminal connection or a signal ground DC Common connection Some potentiostats offer both options and if this is the case only one of the two options should be used ata time preferably the chassis terminal Modern potentiostats are usually designed so that electrode connections working Counter and reference the chassis and the DC Common are alll able to float with respect to the earth ground This floating configuration is considered ideal because it gives the researcher maximum flexibility when working with electrochemical cells that may contain an earth grounded component Compromising the floating configuration by earth grounding either the chassis or the DC Common should be avoided when possible but there are cases where this is the only way to reduce noise in the measured
20. attempt to rotate an electrode tip that has been dropped or otherwise physically damaged Inspect the electrode tip to be certain that it is not damaged AVERTISSEMENT N utilisez pas et ne tentez pas de mettre en rotation un embout d lectrode qui est tomb e ou a t endommag e physiquement d une autre mani re ou d une autre Inspectez l embout d lectrode pour vous assurer qu elle n a pas t endommag e When removing a tip from a shaft or installing a new tip on a shaft use one hand fo prevent the shaft from rotating while using the other hand to gently turn the tip Remove the old tip from the shaft by gently unscrewing the tip by hand No tools are required to remove a tip from a shaft CAUTION AN Do not use tools on the shaft or electrode tip Never use a tool to unscrew a tip from a shaft If a tip cannot be removed from a shaft by hand then contact the factory for further instructions ATTENTION N utilisez pas d outils sur l arbre ou sur l embout d lectrode N utilisez jamais d outil pour d visser un embout d lectrode d un arbre Si un embout d lectrode ne peut tre retir e d un arbre manuellement communiquez avec l usine pour obtenir des instructions suppl mentaires Thread the new tip on to the shaft see Figure 4 4 and gently tighten if by hand Never use a fool to tighten the tip on to the shaft DRU10002 REV 002 APR 201 40 CAUTION Before reconnecting the
21. brush contacts blue is only red and blue used with rotating ring disk electrodes RRDE in which case the lower pair of brushes contact the ring while the upper pair of brushes contact the disk The control unit contains the power supply 10 Control Unit and rotation rate control circuitry 19 2 2 Enclosure Variations The enclosure consists of the enclosure base fabricated from an opaque white polymer and an enclosure window transparent The enclosure window may be a single pane see Figure 2 2 left or it may be assembled from three separate panes see Figure 2 2 right Figure 2 2 Two Styles of Enclosure Window There are four hooks on the enclosure window which are secured to four anchor pins on the enclosure base There are three styles of anchor pins Figure 2 3 Three Styles of Anchor Pins The anchor pins may be simple straight pins see Figure 2 3 left or they may combine a pin with a rubber bumper see Figure 2 3 middle or they may be tapered pins see Figure 2 3 right PINE DRU10002 REV 002 APR 2015 N 0 2 3 Control Unit Components The table and photo below see Figure 2 4 show the control unit components The control unit contains the power supply 10 Control Unit and rotation rate control circuitry Rotation Rate Display 4 2 digit display of rotation rate RPM 2 Rotation Rate Knob 10 turn knob for manual rotation rate control This connection to the control un
22. chemical incompatibility information needed to prevent damage to equipment INCOMPATIBILITE CHIMIQUE Indique un renseignement relatif l incompatibilit chimique requis pour pr venir des dommages l quipement TEMPERATURE CONSTRAINT Indicates when an operation or use of equipment is limited to a specified temperature range CONTRAINTES DE TEMPERATURE Indique lorsqu une op ration ou l usage de mat riel est limit une plage de temp ratures sp cifique Table 1 4 Other Safety Warning Icons used in this Document Tableau 1 4 Autres Ic nes d avertissement de s curit utilis es dans ce document DRU10002 REV 002 APR 2015 1 9 Safety Labels Etiquettes de s curit The following specific safety warnings are found on labels attached to the motor Unit and on the back panel of the control unit Les avertissements de s curit sp cifiques suivants se trouvent sur les tiquettes apposees sur le bloc moteur et sur le panneau arri re de l unit de commande DANGER DANGER Hazardous Tension dangereuse voltage D brancher Disconnect power l alimentation avant before servicing or tout entretien ou cleaning nettoyage Danger Entanglement d enchev trement hazard Arbre en rotation Rotating shaft Rester l cart de Keep clear of l arbre en rotation rotating shaft 1 10 General Safety Warnings Avertissements de s curit g n raux The following safety warnings pe
23. current cathodic current The European Convention 0 1000 cathodic sweep Figure 10 4 Two Popular Voltammogram Plotting Conventions DRU10002 REV 002 APR 2015 128 The same data may be plotted using the European convention see Figure 10 4 right This convention plots anodic currents upward along the vertical axis and more positive anodic oxidizing potentials to the right along the horizontal axis The European convention is more readily understood by those outside the electroanalytical research community because positive values are plotted to the right along the horizontal axis The European convention is used throughout the remainder of this document Note that this choice also implies a mathematical sign convention for the current Specifically positive current values are considered anodic and negative current values are considered cathodic in this document This sign convention is somewhat arbitrary and electrochemical data processing software available from various manufacturers may or may not use this sign convention 10 3 2 Measuring Limiting Currents The theoretical voltamme tric response from a rotating electrode is a symmetric sigmoid shaped wave like the ideal voltammograms shown in Figure 10 3 and Figure 10 4 A perfect sigmoid has a flat baseline current before the wave and a flat limiting current plateau after the wave The height of the wave as measured from the baseline curre
24. depending Upon the internal circuitry of the potentiostat 4 5 2 The Earth Ground Connection On the front panel of the MSR rotator control unit there is an earth ground connection see Figure 4 12 This connection point is in contact with the earth ground via the third prong of the power cord As long as the power system in FINE RESEARCH INSTRUMENTATION 3 51 the laboratory via the third prong offers a robust connection to the earth then this front panel connection can be used as an earth grounding point It is also very important to note that the chassis of the rotator control unit is in direct contact with the earth ground connector Thus if is not possible to isolate the control unit chassis from the third prong earth ground The chassis of the motor unit is also normally connected to the chassis of the control unit and thus to earth ground This connection is usually made in an indirect fashion Because the motor control cable which connects the motor unit fo the control unit is a shielded cable the shield assures that the chassis of the motor unit and the chassis of the control unit are electrically connected And because the control unit chassis is connected to earth ground the motor Unit Chassis is also in contact with earth ground Note Newer rotators have a shielded motor control cable which has s HD 15 connectors on each end of the cable The shield line in this cable assures that the c
25. ee eeccececeecccceecceecececccccccecccceceeeeeeees AFEDOSOPO40PD Platinum Disk Insert 5 mm OD x4 MM PIERRE AFEDOSOPO40PT Silver Disk Insert 5 mm OD x 4 mm THICK ccccscccsssssssvevssssscscnerssesssesssesssssesessseccees AFEDOSOPO40AG Tantalum Disk Insert 5 mm OD x4 MM thiCk asissnshacecnesntessansbavecteansvsineatavedeesntuecveabeveees AFEDOSOPO40TA Titanium Disk Insert 5 MM OD x 4 mm NICK oo ccccceceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees AFEDOSOPO40TI Tungsten Disk Insert 5 MM OD x 4 mm THICK wo ccc ccccscceccccsesceseessessseceeeseseeseseess AFEDOSOPO40W Zinc Disk Insert 5 mm OD x4 MM thick serein AFEDOSOPO40ZN CAUTION A Maximum Rotation Rate 2000 RPM Do not rotate at rates higher than the maximum rotation rate ATTENTION Vitesse de rotation maximum 2000 TR MIN Ne mettez pas l appareil en rotation des vitesses sup rieures la vitesse de rotation maximum i OPERATING TEMPERATURE RANGE 15 C to 25 C Do not use this electrode outside the operating temperature range 68 E5 Series RDE Tips These RDE fips feature a 15 mm OD Teflon shroud around a 5 mm OD disk electrode These tips fit the standard RRDE shaft and may be used af rotation rates up to 3000 RPM Standard disk materials include gold platinum and glassy carbon Other materials are available Upon request Description Part Number Precision RDE amp RRDE Shaft for 15 MM OD TIPS uu ns AFE6MB Glassy Carbon RDE Tip 5 mm OD disk 15 MM
26. electrochemistry in liquid solutions diffusion is a time dependent process consisting of random motion of ions or molecules in solution which leads to the statistical distribution of these species gradually spreading the ions and molecules through the solution A factor of proportionality representing the amount of substance diffusing across a unit area through a unit concentration gradient in unit time Mass transport fo a rotating electrode occurs via a combination of convection and diffusion AS material approaches the electrode diffusion dominates over convection as the principle means of transport Across the very thin layer of solution immediately adjacent to the electrode diffusion is essentially the only means of mass transport This thin layer is known as the diffusion layer The diffusion layer should not be confused with the stagnant layer The diffusion layer exists entirely within the thicker stagnant layer see also Stagnant Layer Some rotating disk and ring disk electrode tips are designed to accept interchangeable disk inserts fabricated from various precious metals and advanced carbon materials The Eisenberg equation describes the mass transfer limited current at a rotating cylinder electrode An adjective used to describe a molecule or ion capable of being oxidized or reduced af an electrode surface An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit Common e
27. makes little or no contribution fo the observed current The opposite extreme involves forced convection where the solution is actively stirred or pumped in a controlled manner At first glance if may seem that the simplest and most obvious way to account for convection Is to try to eliminate if entirely by using a quiescent non moving solution This is the approach used in many popular electroanalytical techniques including cyclic voltammetry chronoamperometry square wave voltammetry and differential pulse voltammetry The timescale for these methods is generally less than 30 seconds and on such short timescales the influence of convection in an unstirred solution is generally negligible On longer timescales however even unstirred solutions are prone to convective interference from thermal gradients and subtle environmental vibrations For long duration steady state experiments convection is unavoidable so actively forcingl1 the solution to move in a well defined and controlled manner is the preferred approach An entire family of electroanalytical methods broadly categorized as hydrodynamic voltammetry couples precise control of solution flow with rigorous mathematical models defining the flow Some of the many examples of hydrodynamic voltammetry include placing an electrode in a flow cell firing a jet of solution at an electrode target 4 embedding an electrode in a microfluidic channel l vibrating a wire shaped electrode
28. maximum rotation rate limitation Consult the documentation for the specific electrode being used in order to learn the maximum rotation rate for that electrode ATTENTION Ne d passez pas la vitesse de rotation maximum pour une lectrode Chaque type d lectrode rotative poss de une vitesse de rotation maximum sp cifique Consultez la documentation pour l lectrode sp cifique utiliser pour conna tre la vitesse de rotation maximum de l lectrode 61 CAUTION Do not apply excessive twisting force to the shroud of an electrode tip when threading it on to the shaft as this may cause a leak between the shroud and the electrode ATTENTION N appliquez pas une force de torsion excessive l enveloppe de protection d un embout d lectrode lorsque vous la vissez sur l arbre car cela pourrait provoquer une fuite entre l enveloppe de protection et l lectrode CAUTION Position the motor unit with respect to the glass cell so that the electrode tip is immersed approximately 1 0 cm into the test solution Excessive immersion may corrode the shaft or tip by allowing liquids to seep into the joint between the shaft and tip ATTENTION Positionnez le bloc moteur en fonction de la position de la cellule de verre de telle sorte que l embout d lectrode soit immerg e sur environ 1 cm dans la solution d essai Une immersion excessive peut entrainer la corrosion de l arbre ou d embout d lectrod
29. more properly called the hydrodynamic layer Mass transport across the stagnant layer occurs by a combination of convection and diffusion with diffusion dominating as the material travels closer to the electrode surface see also Diffusion Layer A thermodynamic quantity expressing the free energy of a redox half reaction in terms of electric potential Rate at which the electrode potential is changed when performing a sweep voltammetry method such as cyclic voltammetry A common electrochemical cell arrangement consisting of a working electrode a reference electrode and a counter electrode In the context of rotating ring disk voltammetry the transit time is the average amount of time required for material generated at the disk electrode to be swept over fo the ring electrode Chaotic non laminar flow of solution A plot of current vs potential from an electro analytical experiment in which the potential is swept back and forth between two limits DRU10002 REV 002 APR 2015 150 Window Experiment Working Electrode An experiment with a rotating ring disk electrode where the disk potential is swept slowly between two limits and the ring potential is swept in the same manner as the disk potential but with a constant offset between the ring and disk potentials The electrode at which the redox process of interest occurs While there may be many electrodes in an electrochemical cell the focus of an exper
30. range 73 E6R2 Series HotSpot RRDE Tips These ring disk electrode tips feature a PEEK shroud and a Teflon gap between the permanently mounted disk and ring electrodes The PEEK shroud permits these electrodes to be used at elevated temperatures These tips fit the standard RRDE shaft and may be used at rotation rates up to 3000 RPM Standard disk and ring materials include gold platinum and glassy carbon Other materials are available Upon request Description Part Number Precision RDE amp RRDE Shaft for 15 mm OD MNOS scssscensasesessaasdeventsaatieseesadenctexeseactaatdsscansaieobewsiowes AFE6MB HotSpot RRDE Tip glassy carbon disk pIAtINUM ring aesssessssesessssssrrrrrrrrereseseessssssrrrrrreeees AFE6R2GCPT HotSpot RRDE Tip gold disk pIAtINUM ring 2 nues AFE6R2AUPT HotSpot RRDE Tip platinum disk and ring esessessesessssssrrrrrrrrrrsssessssssssrrrrrrtrrrereseessssseeeeeeeeeees AFE6R2PTPT HotSpot RRDE Tip glassy carbon disk gold ring esssssessssseesessssrrrrrererrssesesssssssrrerrreree AFE6R2GCAU FOTSOOMR OE TiO 90d diik and I i ss cased senna rierren E EErEE ERES LETRES AFE6R2AUAU HotSpot REDE Tip platinum disk gold ring andeinsctvinivinsadwincsteinicdcenialaccteiwiciveetsisuteiniademostcdes AFE6R2PTAU CAUTION A Maximum Rotation Rate 3000 RPM Do not rotate at rates higher than the maximum rotation rate ATTENTION Vitesse de rotation maximum 3000 TR MIN Ne mettez pas l appareil en rotation a des vitesses
31. rotation rates A plot of limiting current vs square root of rotation rate from a Levich study Term used in corrosion science for an experiment in which the electrode potential is changed from an initial value fo final value at a slow and constant rate This technique is similar to linear sweep voltammetry but the sweep rates are much slower and the results are plotted differently DRU10002 REV 002 APR 2015 148 Linear Sweep Voltammetry Mass Transport Limited Current Migration Non Faradaic Current Overpotential Oxidation Quiescent Solution Redox Reduction Reference Electrode Reynolds Number Experiment in which the working electrode potential is swept from initial value to final value af a constant rate while the current is measured The current corresponding to the maximum mass transfer rate of an ion or molecule to an electrode surface In an electroanalytical context the term migration refers to the movement of ions across a solution Under the influence of an electric field The portion of the current observed in an electroanalytical experiment that cannot be attributed to any redox processes occurring at an electrode surface The overpotential is the difference between the formal potential of a half reaction and the potential presently being applied to the working electrode Removal of electrons from an ion or molecule A solution in which there is little or no convection An a
32. the motor If this circuit breaker trios then the circuit breaker can be reset by pressing the RESET button on the front panel 59 5 Electrodes 5 1 Electrode Handling Precautions Rotating electrode tips and shafts are precision research tools machined to tight specifications for proper balance when spinning at high rotation rates When NOt in use an electrode tip should be cleaned dried and stored in its original case When working with electrode shafts and tips soecial care should be taken not to drop the shaft or tip as this will likely throw the shaft or tip off balance WARNING AN Do not use or attempt to rotate an electrode shaft that has been dropped bent or otherwise physically damaged Inspect the shaft to be certain that it is not damaged AVERTISSEMENT N utilisez pas et ne tentez pas de mettre en rotation un arbre d lectrode qui est tomb a t tordu ou a t endommag physiquement d une autre mani re ou d une autre Inspectez l arbre pour vous assurer qu il n a pas t endommag WARNING AN Do not use or attempt to rotate an electrode tip that has been dropped or otherwise physically damaged Inspect the electrode tip to be certain that it is not damaged AVERTISSEMENT N utilisez pas et ne tentez pas de mettre en rotation un embout d lectrode qui est tomb e ou a t endommag e physiquement d une autre mani re ou d une autre Inspectez l embout d lectrode pour
33. the disk electrode which ultimately makes its way fo the ring electrode It Is offen expressed as a percentage and typical collection efficiencies fall between 20 and 30 Collection Experiment An experiment with a rotating ring disk electrode where the ring potential is held constant while the disk potential is swept slowly between two limits Convection Convection is the movement of molecules or ions through a liquid solution as a result of bulk movement of the solution Such bulk movement may be due to stirring the solution or due to vibrations or thermal gradients in the solution Counter Electrode The counter electrode offen also called the auxiliary electrode is one of three electrodes found in a typical three electrode voltammetry experiment The purpose of the counter electrode is fo help carry the current across the solution by completing the circuit back fo the potentiostat Cyclic Voltammetry An electroanalytical method where the working electrode potential is repeatedly swept back and forth between two extremes while the working electrode current is measured Cylinder Insert Most rotating cylinder electrode tips are designed to accept cylinder inserts fabricated from various alloys of interest fo corrosion scientists DRU10002 REV 002 APR 2015 146 Diffusion Diffusion Coefficient Diffusion Layer Disk Insert Eisenberg Equation Electroactive Electrode Electrode Materials In the context of
34. the front panel the rotation rate indicated by the optical tachometer and the rotation rate indicated at the OUTPUT jack on the front panel should all agree to within one percent 1 0 The readings noted during this step should be recorded in a log book or on a certification sheet DRU10002 REV 002 APR 2015 98 Note l A convenient certification sheet that can be used to record the verification readings from the previous step can be found at the end of this procedure Switch off power to the rotator and disconnect the power cord Use a small 5 64 hex key to loosen the hex screws in the motor coupling and remove the shaft from the rotator Use the hex key to securely retighten the hex screws into the motor coupling Close the clamshell doors on the brush chamber and secure the latch Secure the enclosure around the rotator motor unit see Figure 4 6 WARNING AN Rotating shaft Very high rotation rates The next part of the calibration procedure involves rotation rates at or above 10000 RPM Before continuing verify each of the following points e Verify that the shaft has been removed from the rotator e Verify that the hex screws in the motor coupling are tightened e Verify that the clamshell doors are closed and latched e Verify that the enclosure window is secured to all four pins as shown below AVERTISSEMENT Arbre en rotation Vitesses de rotation extr mement lev es La proch
35. to run at 1000 RPM for at least eight 8 hours This rotation period wears a concave groove into the new brush This intentional wear actually improves the electrical contact between the brush and the shaft 6 2 2 Complete Brush Assembly Replacement In the event that the main body of the brush assembly is damaged if may be necessary to replace the entire brush assembly A Turn off the power to the rotator and disconnect the power cord from the power source before continuing with this procedure AVERTISSEMENT WARNING Rotating shaft Entanglement hazard Arbre en rotation Danger d enchev trement Eteignez le rotateur et d branchez le cordon d alimentation de la source d alimentation avant de poursuivre cette proc dure 81 Remove the old brush assembly from the rotator by unscrewing if as shown below Remove the old brush assembly by hand Use tools only if necessary Install the new brush assembly by threading if by hand into the side of the rotator Do not use tools to tighten the brush assembly are lt G _ y gt INTENTIONAL WEAR PERIOD After installing a new brush install a shaft and allow the rotator x to run at 1000 RPM for at least eight 8 hours This rotation period wears a concave groove into the new brush This intentional wear actually improves the electrical contact between the brush and the shaft 6 3 Lower Bearing Replacement The lower bearin
36. vous assurer qu elle n a pas t endommag e DRU10002 REV 002 APR 2015 60 WARNING Do not use an electrode shaft which appears to wobble vibrate or tilt away from the axis of rotation while rotating Such a shaft is either improperly installed or physically damaged Turn off the rotator disconnect electrical power and remove the shaft immediately AVERTISSEMENT N utilisez pas un arbre d lectrode qui semble osciller vibrer ou d vier de l axe de rotation pendant la rotation Cet arbre est soit install de mani re incorrecte soit endommag physiquement teignez le rotateur d connectez l alimentation lectrique et retirez l arbre imm diatement WARNING Do not use an electrode tip which appears to wobble vibrate or tilt away from the axis of rotation while rotating Such an electrode tip is either improperly installed or physically damaged Turn off the rotator disconnect electrical power and remove the electrode tip immediately AVERTISSEMENT N utilisez pas un embout d lectrode qui semble osciller vibrer ou d vier de l axe de rotation pendant la rotation Cet embout d lectrode est soit install e de mani re incorrecte soit endommag e physiquement teignez le rotateur d connectez l alimentation lectrique et retirez l embout d lectrode imm diatement CAUTION Do not exceed the maximum rotation rate for an electrode Each type of rotating electrode has a specific
37. warranty is expressly in lieu of all other warranties expressed or implied and all other liabilities All specifications are subject to change without notice The CUSTOMER is responsible for charges associated with non warranted repairs such charges including but not limited to travel expenses tariffs labor parts and freight charges This warranty does not apply to shafts electrodes glassware or other accessories that are used in conjunction with the WARRANTED INSTRUMENT 1 6 Instrument Markings Labels on the control unit and motor unit bear information fo identify the MSR rotator and fo indicate any certifications or independent testing agency marks which pertain to the instrument see Figure 2 4 1 6 1 Certifications and Listings marking See the CE Declaration of Conformity attached to the end of this C 4 The MSR rotator complies with one or more EU directives and bears the CE manual for more details The MSR rotator is listed by Intertek to UL 61010 1 issued 11 MAY 2012 Ed 3 q CSA C22 2 61010 1 issued 11 MAY 2012 Ed 3 and IEC 61010 1 issued 10 c us JUN 2010 Corrigendum 1 11 MAY 2011 Intertek is a Nationally Recognized Drertek Testing Laboratory NRTL recognized by the United States Occupational Safety and Health Administration OSHA 1 6 2 Serial Number For purposes of uniquely identifying a particular instrument there is a label on the back panel of the control unit which indicates the model numbe
38. 4 7 2 Monitoring the Rotation Rate The rotation rate is always displayed on the front panel but if can also be monitored at the output jacks on the front panel of the control unit The signal presented at the output jacks is a voltage which is proportional to the rotation rate The proportionality ratio is 1 0 MV RPM Note The rotation rate is controlled to within 1 0 of the display value selected using the rotation rate control knob It is normal for the last one or two digits on the display to flicker _ DRU 10002 REV 002 APR 2015 56 4 7 3 External Control of the Rotation Rate It is offen Convenient for the rotation rate to be controlled via an externally supplied signal Many potentiostats are capable of providing such a signal to control the rotation rate while simultaneously performing electrochemical measurements An externally supplied signal is also required when performing hydrodynamically modulated voltammetry where the rotation rate is varied sinusoidally as electrochemical measurements are made with the potentiostat Figure 4 15 Connecting the Rotation Rate Control Cable A special cable is available to connect Pine potentiostats fo the MSR rotator see Figure 4 15 One line of this cable carries an analog rate control signal from the potentiostat to the INPUT jacks on the front panel of the control box A second line carrying a digital control signal is connected to the MOTOR STOP jack on the back pan
39. 5 C to 25 C Do not use this electrode outside the operating temperature range 67 E4TQ Series ChangeDisk RDE Tips These RDE tips feature a 12 mm OD Teflon holder which can accept a removable disk insert These tips fit the standard RDE shaft and may be used aft rotation rates up to 2000 RPM The disk insert 5 mm OD x 4 mm thick is typically fabricated from gold platinum or glassy carbon Other disk materials are available Upon request Description Part Number Standard RDE Shaft for 12 mm OD RD BOS cect den ten een ce ess AFE3M ChangeDisk RDE tip 12 mm OD shroud accepts 5 mm OD x 4 mm thick disks AFE4TQO50 Toolkit for removing and polishing disk inserfs AFE4KO50 Glassy Carbon Disk Insert 5 mm OD x 4 MM THICK csssracaecerscastacarcoeicaevecteasinasvesnanabes AFEDO50P040GC Basal Plane Pyrolytic Graphite Disk Insert 5 mm OD x 4 MM thick AFEDO50P040GB Edge Plane Pyrolytic Graphite Disk Insert 5 mm OD x 4 MM fhick AFEDOSOPO40GE Aluminum Disk Insert 5 MM OD x 4 mm TICK oo ccccccceceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees AFEDOSOPO40AL Copper Disk Insert 5 mm OD x4 Mm TICK ciccsscscscsstcsencceacseassstessascedeacasesdeteaecedcscasestes AFEDOSOPO40CU Gold Disk Insert 5 mm OD x 4 mm thick ns rer ere AFEDOSOPO40AU Nickel Disk Insert 5 mm OD x 4 mm THICK cccccccccccssssssssessssssnceressccceesessssssseessssssees AFEDOSOPO4ONI Palladium Disk Insert 5 MM OD x 4 MM ihick
40. 5 in 29 x 26 x 15 cm 18 8 x 15 5 x 21 0 in 48 x 40 x 54 cm 10 C fo 40 C 50 F to 104 F motor power 15 W supply voltages 30 VDC 24 VDC motor type permanent magnet shipping weight shipping dimensions control unit rotator enclosure 2 Amp thermal type circuit breaker current limited power supplies 28 3 millinewton meters closed loop servo system temperature compensated tachometer mounted on motor shaft 4 2 digit display indicates rotation rate RPM 100 to 200 RPM accurate to within 2 counts of display reading 200 to 10 000 RPM accurate to within 1 of display reading front panel 10 turn rotation rate control knob button to reset circuit breaker back panel power switch allows optional external signal to control rotation rate banana jack selectable control ratio 1 RPM mV default 2 RPM mvV 4 RPM mvV allows optional external monitoring of rotation rate banana jack output signal ratio 1 MV RPM 1 0 back panel input optional digital motor stop signal banana jack metal binding post banana jack connects to ground lead of power cord and to control unit chassis DC common 3 black banana jacks isolated from earth ground approximately 300 000 RPM sec maximum no load gt 50 Hz 1 dB at 1000 RPM peak to peak modulation on a 2000 RPM base rate 1 8 Icons Ic nes Special icons see Tables 1 2 1 3 and 1 4 are used fo call attention to safety warnings and other useful
41. 98 1317 1327 31 E Higuchia H Uchidab and M Watanabe Effect of loading level in platinum dispersed carbon black electrocatalysts on oxygen reduction activity evaluated by rotating disk electrode J of Electroanalytical Chem 583 2005 69 76 32 ZD Weia SH Chanb LL Lia HF Caia ZT Xiab and CX Sunc Electrodepositing Pt on a Nafion bonded carbon electrode as a catalyzed electrode for oxygen reduction reaction Electrochimica Acta 50 2005 2279 2287 33 S Marcotte D Villers N Guillet L Rou and JP Dodelet Electroreduction of oxygen on Co based catalysts determination of the parameters affecting the two electron transfer reaction in an acid medium Electrochimica Acta 50 2004 179 188 34 S Duron R Rivera Noriega P Nkeng G Poillerat and O Solorza Feria Kinetic study of oxygen reduction on nanoparticles of ruthenium synthesized by pyrolysis of Ru3 CO i2 J of Electroanalytical Chem 566 2004 281 289 35 DR Gabe and FC Walsh Enhanced Mass Transfer at the Rotating Cylinder Electrode Characterization of a Smooth Cylinder and Roughness Development in Solutions of Constant Concentration J Appl Electrochem 14 1984 555 36 DR Gabe and FC Walsh Enhanced Mass Transfer at the Rotating Cylinder Electrode ll Development of Roughness for Solutions of Decreasing Concentration J Appl Electrochem 14 1984 565 37 DR Gabe and FC Walsh Enhanced Mass Transfer at the Rotating Cylinder Electrode il Pilot and Production Plant E
42. Adjust trimmer P2 until the voltmeter reads 0 0000 VDC 0 0005 VDC Keep the red lead of the digital voltmeter connected to testpoint TP2 on the circuit board Adjust trimmer P3 until the voltmeter reads approximately 0 0125 VDC At this point the motor should be rotating at a very slow rate The direction of this slow rotation should be counterclockwise when looking down on the motor unit from above Turn the rotation rate control knob very slowly until the motor comes to a complete stop Adjust trimmer P7 until the rotation rate display on the front panel reads 0000 1 Connect the red lead of the digital voltmeter to the OUTPUT signal jack on the front panel Confirm that the signal level at this jack is 0 000 VDC 0 001 VDC Using the tachometer to monitor the actual rotation rate slowly adjust the rotation rate knob on the front panel until the tachometer indicates a rotation rate of 3000 RPM 1 RPM While the shaft is rotating at 3000 RPM adjust trimmer P6 until the rotation rate display on the front panel of the control unit reads 3000 1 Connect the red lead of the digital voltmeter to the OUTPUT signal jack on the front panel Confirm that the signal level at this jack is 3 000 VDC 0 001 VDC Slowly turn the rotation rate control knob counterclockwise until the motor comes to a complete stop Connect a DC voltage source to the rotation rate input signal jacks on the front panel of the control unit The positive lead fro
43. Assembly 23 Figure 2 5 Motor Unit Components LLL DRU10002 REV 002 APR 2015 24 2 5 Typical Rotating Disk Electrode Design Most rotating disk electrodes consist of two parts see Figure 2 6 a shaft and a tio but in some cases the entire electrode may be a single piece Figure 2 6 Typical Rotating Disk Electrode RDE Tip with Shaft Teflon PEEK or KEL F Fiached Surface The electrode surface Is typically polished to Insulating Shroud on Tip This insulating shroud material is typically mirror smoothness 38 Threads on Shaft These threads are normally in electrical contact with disk 57 tea inside Tip re or Pa normally in electrical This insulating shroud material is typically Insulating Shroud on Shaft Teflon PEEK or KEL F 41 Disk Contact Area This metal area on the shaft is normally in electrical contact with disk This electrically isolated portion of the shaft Shaft Mounting Area is used to physically mount the shaft in the motor coupling 2 6 Typical Rotating Ring Disk Electrode Design Rotating ring disk electrode tips mount on fo a special two conductor shaft see Figure 2 7 In some cases the fip can be taken apart info smaller pieces Figure 2 7 Typical Rotating Ring Disk Electrode RRDE Tip with Shaft Insulating Shroud on Tip ee pee he material is typically Plastic Cover Cover protects electrode when not in use 45 Ring Threads on Tip These threads contac
44. D AFEZR8AUPT ThinGap RRDE Tip platinum disk gold ring 180 um gap eesesssssssssssssssssssssssssssssssssssssssss AFE R8PTAU CAUTION A Maximum Rotation Rate 3000 RPM Do not rotate at rates higher than the maximum rotation rate ATTENTION Vitesse de rotation maximum 3000 TR MIN Ne mettez pas l appareil en rotation des vitesses sup rieures la vitesse de rotation maximum re OPERATING TEMPERATURE RANGE 15 C to 25 C Do not use this electrode outside the operating temperature range 75 5 6 15 mm OD RCE Tips Complete rotating cylinder electrode RCE systems for the MSR rotator are available These systems use a 15 mm diameter cylinder geometry 15 mm OD RCE System A typical 15 mm OD RCE system includes a 15 mm OD RCE shaft a one lifer corrosion cell equipped with a center port gas purged bearing assembly a means of heating the contents of the cell and other accessories The RCE shaft is able to accept standard cylinder samples 15 mm OD x 6 3 mm fall fabricated from carbon steel or various stainless steels Contact Pine for more details about this system CAUTION Maximum Rotation Rate 4000 RPM Do not rotate at rates higher than the maximum rotation rate ATTENTION Vitesse de rotation maximum 4000 TR MIN Ne mettez pas l appareil en rotation des vitesses sup rieures la vitesse de rotation maximum re OPERATING TEMPERATURE RANGE 10 C to 80 C Do not use this electrode outside th
45. D Simonsson Enhanced Mass Transfer to a Rotating Cylinder Electrode with Axial Flow J Appl Electrochem 18 1988 710 KD Efird EJ Wright JA Boros and TG Hailey Correlation of Steel Corrosion in Pipe Flow with Jet Impingement and Rotating Cylinder Tests Corrosion 49 1993 992 DC Silverman Rotating Cylinder Electrode for Velocity Sensitivity Testing Corrosion 40 1984 220 DC Silverman and ME Zerr Application of the Rotating Cylinder Electrode E Brite 26 1 in Concentrated Sulfuric Acid Corrosion 42 1986 633 DC Silverman Rotating Cylinder Electrode Geometry Relationships for Prediction of Velocity Sensitive Corrosion Corrosion 44 1988 42 DC Silverman Corrosion Prediction in Complex Environments using Electrochemical Impedance Spectroscopy Electrochimica Acta 38 1993 2075 DC Silverman On Estimating Conditions for Simulating Velocity Sensitive Corrosion in the Rotating Cylinder Electrode Corrosion 55 1999 1115 DC Silverman Technical Note Simplified Equation for Simulating Velocity Sensitive Corrosion in the Rotating Cylinder Electrode at Higher Reynolds Numbers Corrosion 59 2003 207 DC Silverman The Rotating Cylinder Electrode for Velocity Sensitive Corrosion A Review Corrosion 60 2004 1003 DC Silverman Technical Note Conditions for Similarity of Mass Transfer Coefficients and Fluid Shear Stresses between the Rotating Cylinder Electrode and Pipe Corrosion 61 2005 515 G Wranglen J Berendso
46. Description Part Number Description Part Number Power Supply 30 V 100 W ACOIM30V Power Supply 24 V 65 W ACO1M24V Figure 7 3 Replacement Internal Power Supplies 115 WARNING Risk of electric shock Disconnect all power before servicing the rotator AVERTISSEMENT Risque de d charge lectrique D connectez toutes les sources d alimentation avant de proc der l entretien du rotateur WARNING Rotating shaft Entanglement hazard Turn off the power to the rotator and disconnect the power cord from the power source before continuing with this procedure AVERTISSEMENT Arbre en rotation Danger d enchev trement Eteignez le rotateur et d branchez le cordon d alimentation de la source d alimentation avant de poursuivre cette proc dure DRU10002 REV 002 APR 20 116 8 Troubleshooting This section describes some basic troubleshooting considerations when working with a rotator If problems with the rotator persist contact the factory for further assistance see Section 1 5 Suggested Cause or Action No Rotation Confirm that the unit is connected to a live power outlet Confirm that the power switch has not tripped and that it is in the on position Reset the switch if necessary Check the front panel circuit breaker and reset the breaker if necessary Check the motor control cable which connects the control unit to the motor unit The connectors at both ends of this
47. Do not rotate at rates higher than the maximum rotation rate ATTENTION Vitesse de rotation maximum 3000 TR MIN Ne mettez pas l appareil en rotation des vitesses sup rieures la vitesse de rotation maximum i OPERATING TEMPERATURE RANGE 10 C to 80 C Do not use this electrode outside the operating temperature range Da CHEMICAL INCOMPATIBILTY The shroud material PEEK may be discolored by prolonged exposure to concentrated acids Note gt RDE tips with PEEK shrouds are considerably more difficult to polish by hand than 1 tips with Teflon shrouds Mechanical polishing is recommended if the appropriate equipment is available 71 5 4 Single Piece RDE Designs Electrode designs where the electrode tip is permanently mounted on the shaft are called single piece electrodes E2 Series FastSpeed RDEs These single piece rotating disk electrodes are ideal for applications requiring a high rotation rate up to 7000 RPM The shroud is fabricated from chemically resistant Teflon Standard disk materials include gold platinum and glassy carbon but other materials are available upon request Description Part Number Glassy Carbon FasiSpeed RDE 5 mm OD disk 12 mm OD shroud ce eeeeeeeee AFE2MO50GC Basal Plane Pyrolytic Graphite FastSoeed RDE 5 mm OD disk 12 mm OD shroud AFE2MO50GB Edge Plane Pyrolytic Graphite FastSoeed RDE 5 mm OD disk 12 mm OD shroud AFE2MOSOGE Aluminum FastSpeed RDE 5 mm OD d
48. EV 002 APR 201 14 2 Description The MSR rotator provides excellent steady state control of constant rotation rates but if also offers outstanding acceleration deceleration control for those applications where the rotation rate must be modulated The base rotation rate for steady state constant rate control may be manually adjusted from 50 to 10 000 RPM by turning a ten turn potentiometer knob located on the front panel of the control unit As the knob is turned a built in tachometer measures the actual rotation rate and this rate is continuously displayed on the front panel of the control unit Manually turning the knob and observing the rotation rate is by far the most common manner in which the rotation rate is selected More complex control of the rotation rate is possible when the MSR rotator is connected to a potentiostat system capable of supplying an analog rotation rate signal While specific details vary from one system to another the basic idea is that the potentiostat produces an analog signal that is proportional to the target rotation rate This analog signal is carried by a cable supplied by the potentiostat manufacturer to a pair of input banana jacks on the front panel of the MSR rotator s control unit This connection permits the software which controls the potentiostat to control the rotation rate using a constant voltage level for steady state rotation or a more complex waveform such as a sine wave for hydro
49. Modulated Speed Rotator MSR User Guide Pine Research Instrumentation Inc 2741 Campus Walk Avenue Building 100 Durham NC 27705 USA hito www pineinst com echem Phone 1 919 782 8320 Fax 1 919 782 8323 Copyright 2013 2015 Pine Research Instrumentation Inc All Rights Reserved f2 at DRU10002 REV 002 APR 2015 Table of Contents Preface 1 1 Scope 1 2 Copyright 1 3 Trademarks 1 4 Use Limitation 1 5 Service and Warranty Information 1 6 Instrument Markings 1 6 1 Certifications and Listings 1 6 2 Serial Number 1 6 3 Model Numbers 1 7 Specifications 1 8 Icons Ic nes 1 9 Safety Labels Etiquettes de s curit 1 10 General Safety Warnings Avertissements de s curit g n raux Description 2 1 Major System Components 27 Enclosure Variations 2 Control Unit Components 2 4 Motor Unit Components 2 5 Typical Rotating Disk Electrode Design 2 6 Typical Rotating Ring Disk Electrode Design Installation 3 1 Site Preparation a2 Unpacking and Setting Up the Rotator Operation 4 1 The Rotating Shaft 4 1 1 Installing a Shaft 4 1 2 Changing the Tip on a Shaft 4 2 Mounting the Cell 4 3 The Enclosure 4 4 Cell Connections 4 4 1 RDE and RCE Wiring 4 4 2 RRDE Wiring 4 4 3 Routing Cables and Tubing 4 5 Proper Grounding 4 5 1 Terminology 4 5 2 The Earth Ground Connection 4 5 3 A Typical Grounding Strategy 4 6 Using the Rotator in a Glove Box 4 7 Rotation Rate Control 4 7 1 Manual Control of Rotation 4 7 2 Monit
50. N 111 This cord is for Use in India and South Africa This cord is for use exclusively in Israel Description Part Number Description Part Number Power Cord IMOIl 8 EWMI8B8IN Power Cord Israel EWM 18B8IL This cord is for use exclusively in Japan This cord is for use exclusively in Argentina Description Part Number Description Part Number Power Cord Japan EWMI8B8JP Power Cord Argentina EWM 18B8AR This cord is for use exclusively in Denmark This cord is for use in Australia amp New Zealand Description Part Number Description Part Number Power Cord Denmark EWM18B8DK Power Cord Australiad nesses EWM 18B8NZ DRU 10002 REV 002 APR 2015 This cord is for use exclusively in Switzerland This cord is for use exclusively in Italy Description Part Number Description Part Number Power Cord Switzerland EWM18B8CH Power Cord Italy EWM18B8IT 113 7 3 Power Supplies The rotator control unit has two internal power supplies One of these power supplies is 30 VDC 100 W and the other is 24 VDC 65 W These power supplies are located within the high voltage section of the control unit see Figure 7 2 GANGER HIGH VOLTAGE 2 HAUTE Figure 7 2 Location of High Voltage Power Entry and Internal Power Supplies WARNING Risk of electric shock Disconnect power before servicing the control unit The shaded region in
51. Stainless Steel Bearing Assembly ACMR3301X Ceramic Bearing Assembly ACMR3302 Enclosure Parts The complete enclosure kif consists of everything in the photo above The enclosure window and flask support post are also available separately Description Part Number Complete Enclosure Kit AFMSRCE ENCL Three Pane Enclosure Window ACMRNOS Flask Support Post 5 8 OD ACO1MSRD Three Prong Lab Clamp This three pronged clamp fits a 24 25 center joint on an electrochemical cell Standard right angle bracket is included Description Part Number Three Prong Cam ss AKCLAMP Round Cell Clamp This clamp is for use with large round cells with outer diameters between 140 and 165 mm Standard right angle bracket Is included Description Part Number Round Cell CIAMP ce eeeeeeeees AKCLAMP2 Cell Platform The cell platform is fabricated from a chemically resistant polymer and mounts anywhere along the center post Description Part Number C CIIFAGHTIORN annn enn anna ACPR103 mm Rotation Rate Calibration Kit This kit contains a handheld tachometer timmer adjustment tool and a shaft with a reflective target see Section 6 6 for instructions regarding the use of this kit Description Part Number Rotation Rate Calibration Kit AKMSRCAL 109 Motor Control Cable The motor control cable has HD 15 connectors on either end and is used
52. TTENTION Vitesse de rotation maximum 3000 TR MIN Ne mettez pas l appareil en rotation des vitesses sup rieures la vitesse de rotation maximum i OPERATING TEMPERATURE RANGE 15 C to 25 C Do not use this electrode outside the operating temperature range 69 E5TQ Series ChangeDisk RDE Tips These RDE fips feature a 15 mm OD Teflon shroud which accepts a 5 mm OD removable disk insert These Tips fit the standard RRDE shaft and may be used at rotation rates up to 3000 RPM Standard disk inserts are fabricated trom gold platinum and glassy carbon Other disk materials are available upon request Description Part Number Precision RDE amp RRDE Shaft for 15 mm OD TOS esse scsusesessvssarisesdionaedsasevesavudeverdaarcvacomndaracdunsdvevesds AFE6MB ChangeDisk RDE tip 15 mm OD shroud accepts 5 mm OD x 4 mm thick disks AFESTQO50 Toolkit for removing and polishing disk inserts ccccccccccccccccccccccccccccccccccccccecccceccecceeeeceeeeess AFE6K050 Glassy Carbon Disk Insert 5 mm OD x 4 MM TIGR ses icssceenidccsscesoctoscchseiomiceeteoradinien AFEDO50P040GC Basal Plane Pyrolytic Graphite Disk Insert 5 mm OD x 4 mm nick AFEDO50P040GB Edge Plane Pyrolytic Graphite Disk Insert 5 mm OD x 4 MM fhick AFEDOSOPO40GE Aluminum Disk Insert 5 mm OD x4 MM TINICK ecsenccercneiscentncerarneecutidsertaensenwenienens AFEDOSOPO40AL Copper Disk Insert 5 mm OD x 4 mm fhick ss AFEDOSOPO40CU Gold Disk Insert 5
53. The electrode brushes may deposit silver carbon dust inside the brush chamber and deposit a film on the surface of the rotating shaft A thin film on the shaft actually improves the contact between the brush and the shaft This film does not need to be cleaned off of the shaft unless the film is rough or bumpy 6 2 Brush Replacement The brushes contact the rotating shaft slowly wearing during normal use and periodically the brushes must be replaced A simple brush replacement kit Is available or in the case of serious damage to the entire brush assembly the brush and its Teflon holder can be replaced 6 2 1 Internal Brush Replacement WARNING Rotating shaft Entanglement hazard D Turn off the power to the rotator and disconnect the power cord from the power source before continuing with this procedure AVERTISSEMENT Arbre en rotation Danger d enchev trement Eteignez le rotateur et d branchez le cordon d alimentation de la source d alimentation avant de poursuivre cette proc dure DRU10002 REV 002 APR 2015 78 The standard brush replacement kit contains a small hex key a new brush and a new set screw installed in the brush A special brush replacement kit should be used when the rotator is routinely operated in low humidity conditions such as inside a glove box Part numbers for brush replacement kits are listed in Section 7 1 Remove the entire brush assembly from the rotator by un
54. ack Panels INE DRU10002 REV 002 APR 2015 2 4 Motor Unit Components The table below and the photographs on the next page see Figure 2 5 identity the major components of the motor unit 26 Motor Cable Connector Accepts one end of motor control cable These upper brushes make contact on opposing sides of the rotating shaft and are used to make contact with rotating disk electrodes and rotating cylinder electrodes NO NI NO Upper Brush Pair red These lower brushes make contact on opposing sides of the rotating shaft and are Lower Brush Pair blue used fo make contact with the ring electrode when working with rotating ring disk electrodes These doors open to permit access to the 29 Clamshell Doors CRAE Door Latch Secures clamshell doors in closed position Spring loaded silver carbon brush provides 21 Pisa contac electrical contact with the rotating shaft Motor Coupling Used to attach the shaft to the motor Hex screws located on either side of the motor coupling tighten to hold the shaft inside the motor coupling Motor Coupling Hex Screw Pair CO CD The top end of the rotating shaft is mounted Electrode Shaft in motor coupling and the active electrode surface Is at the bottom end of the shaft CO IK An easily replaceable bearing assembly stabilizes the rotating shaft at the point where the shaft exits the motor unit Metal and ceramic bearings are available 35 Lower Bearing
55. actly zero However if is normal for there to be a small residual rotation rate and often this is in the reverse direction If a negative voltage signal is applied to the INPUT jacks on the front panel of the control unit then the rotator will spin backwards If this is undesirable reverse the polarity of the signal applied to the INPUT jacks Electrical Noise Make sure that working reference and counter in Voltammograms electrode cables do not cross or travel near power environmental cords video cables or network lines Make sure that the potentiostat and rotator are located as far as possible trom hotplates ovens video monitors computers network hubs wireless devices or cellular telephones Electrical Noise Confirm that the earth ground connection on the rotator in Voltammograms is connected to the chassis ground of the potentiostat grounding issues Confirm that all metal objects such as cell clamps and ring stands near the electrochemical cell are connected to the earth ground connection on the rotator see Section 4 5 Confirm that all grounding connections are made to a common grounding point to avoid the formation of grounding loops Note that grounding loops are sometimes non obvious especially when multipole instruments and computers are connected together Electrical Noise Always use a banana jumper cable to connect in Voltammograms opposing brushes together Two brushes in opposing brush we
56. aine partie de la proc dure d talonnage implique des vitesses de rotation sup rieures ou gales 10000 tr min Avant de continuer v rifiez chacun des points suivants e V rifiez que l arbre a t retir du rotateur e V rifiez que les vis hexagonales du raccord avec le moteur sont bien serr es e V rifiez que les portes de la coque sont ferm es et verrouill es e V rifiez que les quatre broches de fermeture de la fen tre du bo tier sont ferm es tel qu indiqu ci dessous 99 Turn the rotation rate knob fully counter clockwise This is the position which corresponds fo a nearly zero rotation rate Reconnect the power cord and carefully switch on the rotator Slowly turn the rotation rate control knob fully clockwise to the fastest rotation rate The rotation rate display on the front panel of the control unit should read approximately 10050 RPM Adjust trimmer P4 until the rotation rate display on the front panel of the control unit reads 10050 RPM 10 RPM Turn the rotation rate knob fully counter clockwise This is the position which corresponds to a nearly zero rotation rate Switch off power to the rotator and disconnect the power cord Replace the cover on the control unit a el SS rl re ne Re ae SN At this point the calibration procedure is complete Make a note in a log book or place a sticker on the control unit to record the calibration date OSes Se a ye
57. amber Align the four screw holes on the new bearing assembly with the four threaded holes in the motor unit Thread the four screws into the holes by hand Then tighten the screws with a flathead screwdriver 83 6 4 Removing the Motor Coupling Assembly On rare occasions such as when replacing a failed motor if may be necessary to remove the motor coupling assembly from the motor unit WARNING Risk of electric shock AN Disconnect all power before servicing the rotator AVERTISSEMENT Risque de d charge lectrique D connectez toutes les sources d alimentation avant de proc der l entretien du rotateur WARNING AN Rotating shaft Entanglement hazard Turn off the power to the rotator and disconnect the power cord from the power source before continuing with this procedure AVERTISSEMENT Arbre en rotation Danger d enchev trement Eteignez le rotateur et d branchez le cordon d alimentation de la source d alimentation avant de poursuivre cette proc dure Disconnect the motor control cable from the top of the motor unit If there is a shaft presently installed in the motor unit remove the shaft Disconnect any signal cables from the brush banana jacks red and blue DRU10002 REV 002 APR 2015 84 There are two screws which hold the cowling in place front and back Use a flathead screwdriver to remove these two screws from the cowling Carefully begin removing t
58. ar contact provide a better electrical connection FINE RESEARCH INSTRUMENTATION 119 Suggested Cause or Action Electrical Noise in Voltammograms cell connections Insoect all brush contacts Brushes should have a concave groove worn in them which exactly mates with the rotating shaft The depth of this concave groove naturally increases over the lifetime of the brush A new brush should be worn continuously for approximately eight hours to intentionally wear a groove into the brush to increase the surface area of the brush that is in contact with the shaft Confirm that the reference electrode has low impedance and is in good contact with the main test solution High impedance at the reference electrode is often caused by a plugged frit which impedes current between the inner chamber of the reference electrode and the main test solution High impedance may also be encountered when working with low dielectric media such as non aqueous solvents Use working reference and counter electrode cables which are shielded coaxial cables Confirm that any alligator clips being used for connection to the electrodes are not corroded and are securely fastened to the electrodes Note that many poftentiostats utilize a driven shield to protect the reference electrode signal This driven shield is Connected to the outer shield line in the coaxial reference electrode cable Only the inner signal line of the coaxial cable s
59. as directement le faisceau laser Ne pointez pas le faisceau laser dans l il Using the tachometer to monitor the actual rotation rate slowly adjust the rotation rate knob on the front panel until the tachometer indicates a rotation rate of approximately 2800 RPM WAITING PERIOD Allow the rotator to rotate at 2800 RPM for one 1 hour before x continuing with the calibration process This waiting period Je permits all electronic and mechanical components of the rotator system to equilibrate and reach a steady state After the one hour waiting period turn the rotation rate knob fully counter clockwise This is the position which corresponds to a nearly zero rotation rate Locate testpoints TP2 and TP3 on the circuit board These testpoints are accessible without the need to remove the circuit board from the control unit PAINE DRU10002 REV 002 APR 2015 96 Connect the black lead of the digital voltmeter fo one of the two black banana jacks DC common on the front panel of the control unit In the next several steps of the procedure the red lead on the voltmeter is connected to various testpoints but the black lead should remain connected fo the DC Common jack on the front panel Connect the red lead of the digital voltmeter to testpoint TP3 on the circuit board Adjust trimmer P3 until the voltmeter reads 0 0000 VDC 0 0005 VDC Connect the red lead of the digital voltmeter to testpoint TP2 on the circuit board
60. ator clips The upper red jacks make electrical contact with a rotating disk electrode RDE or a rotating cylinder electrode RCE tip When using a rotating ring disk electrode RRDE the upper red jacks make contact with the disk and the lower blue jacks make contact with the ring 29 Remove the control unit 10 from the box e ne 4 and place it next to the enclosure base EE Bal Plug the male end of the motor control cable 8 into the motor cable connector on the back of the control unit and plug the female end of the cable info the top of the motor unit CAUTION The connectors on both ends of the motor control cable MUST be firmly secured by tightening the pair of screws on each connector Failure to secure the connectors will result in improper control of the rotation rate ATTENTION Les connecteurs situ s aux deux extr mit s du c ble de commande du moteur DOIVENT tre fermement attach s en serrant les deux vis de chaque connecteur Une mauvaise fixation des connecteurs entra nera un mauvais contr le de la vitesse de rotation Attach the enclosure by hooking it on to the four pins The enclosure will rest securely on the enclosure base DRU 10002 REV 002 APR 2015 30 An appropriate power cord 10 amp rating is provided with the rotator Use this cord to connect the control unit fo the local power supply The local power supply should provide an earth g
61. aux d humidit augmente la vitesse d usure des balais internes du moteur Consultez la section 6 5 pour en savoir plus sur la mani re de remplacer un moteur us 55 4 7 Rotation Rate Control CAUTION A Always turn the rotation rate control knob completely counterclockwise towards the zero rotation rate position before turning on the rotator ATTENTION Ne Tournez toujours le bouton de commande de la vitesse de rotation compl tement dans le sens inverse des aiguilles d une montre vers la position vitesse de rotation gale z ro avant de mettre le rotateur en marche Note The fully counterclockwise position corresponds nominally to a rotation rate of zero Even with the knob in this position there may be some residual rotation typically less than 10 RPM in either the clockwise or counter clockwise direction Always begin each session using the rotator with the power turned off and the rotation rate control knob in the fully counterclockwise position The fully counterclockwise position corresponds to the slowest rotation rate and it is always safest to turn on the rotator with the knob in this position 4 7 1 Manual Control of Rotation To rotate the electrode under manual control turn on the control unit power and slowly turn the rotation rate control knob clockwise As the knob is furned clockwise the rotation rate increases and the display on the control unit shows the rotation rate
62. brush chamber see Figure 4 2 Two clamshell doors surround the brush chamber These doors are securely latched during rotator operation and push two pairs of contact brushes against the rotating shaft The upper red pair of brushes makes contact with the disk or cylinder while the lower blue pair makes contact with the ring on a rotating ring disk electrode tN i LED AR HER ssatsecsnesesnananasestntmensarseananan ee tnenentesesatananeneetnentanenanananane nance aeansneeeasanchanenanaaneetonsessaneeinamanbeeensnanseseanunannneeetneneetneeansanabestnanessesenananabestnenensecen ta anapsnentnansntessnansbasestnenmenasananananent sen asenanasasenesrenssesineanas ene a eseasersosesrenenesesesneesreeeneneneroseerar aes pus rente someamemnas es teas tif RESEARCH INSTRUMENTATION j y 33 4 1 1 Installing a Shaft A WARNING Rotating shaft Entanglement hazard Turn off the power to the rotator and disconnect the power cord from the power source before installing or removing the electrode shaft or before installing or removing an electrode tip on the end of the shaft AVERTISSEMENT Arbre en rotation Danger d enchev trement teignez le rotateur et d branchez le cordon d alimentation de la source d alimentation avant d installer ou d enlever l arbre de l lectrode ou avant d installer ou d enlever un embout d lectrode l extr mit de arbre WARNING Do not use or attempt to rotate an electrode shaft t
63. cable must be secured using the two screws on each connector The rotation rate knob may be set to full counterclockwise position If this is the case then rotate the knob clockwise to increase the rotation rate The motor the shaft or one of the bearings may be frozen due fo corrosion or one of the boards or cables may be loose Turn off the rotator disconnect power and then try the following procedure WARNING Risk of electric shock Disconnect all power before servicing the rotator AVERTISSEMENT Risque de d charge lectrique D connectez toutes les sources d alimentation avant de proc der l entretien du rotateur Check for freedom of rotation of the shaft by manually attempting to rotate the shaft Look inside the control unit and confirm that the printed circuit board Is fully inserted info ifs connector 117 Suggested Cause or Action Continuous Check the motor control cable which connects the Rotation ata control unit fo the motor unit The connectors at both High Rate ends of this cable must be secured using the two screws on each connector Faulty connection or wire contact the factory Faulty circuitry contact the factory System Power Loss The main power switch on the back panel is a circuit breaker which may trip and cause the system fo lose power To reset the breaker turn the switch off and then turn the switch on again Repeated tripping may indicate a more serious problem F
64. ctronic instruments Each end of the cable has a banana plug The plug consists of a cylindrical metal pin about 25 mm one inch long with an outer diameter of about 4 mm which can be inserted info a matching banana jack Female banana connector Male banana connector The BNC Bayonet Neill Concelman connector is a very common type of RF connector used for terminating coaxial cable Electrical contact fo the rotating shaft is accomplished by means of silver carbon brush contacts These brushes are spring loaded fo assure that they are firmly pressed against the rotating shaft at all times Flow of charge at an electrode as a result of a reduction reaction occurring at the electrode surface For a working electrode immersed in a test solution a cathodic current corresponds to flow of electrons out of the electrode and into the solution 145 Coaxial Cable Coaxial cable coax is an electrical cable with an inner Conductor surrounded by a flexible tubular insulating layer surrounded by a tubular conducting shield The term coaxial comes from the inner conductor and the outer shield sharing the same geometric axis Coaxial cable is offen used to carry signals from one instrument to another in situations where it is important to shield the signal from environmental noise sources Collection Efficiency In the context of rotating ring disk voltammetry the collection efficiency is a measure of the amount of material generated at
65. cules or ions tend to be oxidized and conversely if a sufficiently negative potential is applied to the rotating electrode the molecules or ions tend to be reduced Reduction at a rotating electrode implies that electrons are being added to the ion or molecule by flowing out of the electrode and into the solution A current travelling in this direction is said to be a cathodic current The general form of a reduction halt reaction occurring at an electrode may be written as follows O ne R where Rrepresents the reduced form of the molecule or ion O represents the oxidized form of the molecule or ion and n is the total number of electrons added to the molecule or ion when if is converted from the oxidized form O to the reduced form R Oxidation at a rotating electrode implies that electrons are being removed from an ion or molecule and are travelling out of the solution and into the electrode A current travelling in this direction is said to be an anodic current and the oxidation occurring at the electrode can be represented by the following redox half reaction R O ne Given that electrochemical half reactions can occur in either direction they are often written using chemical equilibrium notation as follows O ne R By convention redox half reactions are generally tabulated in textbooks and other reference works as reduction reactions with the oxidized form on the left side and the reduced form on the
66. cy 135 10 5 2 Empirical Measurement of the Collection Efficiency 136 10 5 3 Generator Collector Experiments 137 10 5 4 Comparing Two Competing Pathways 137 10 6 Rotating Cylinder Electrode RCE Theory 140 10 7 References 141 11 Glossary 144 FINE RESEARCH INSTRUMENTATION 5 DRU 10002 REV 002 APR 20 Figure 2 1 Figure 2 2 Figure 2 3 Figure 2 4 Figure 2 5 Figure 2 6 Figure 2 7 Figure 4 1 Figure 4 2 Figure 4 3 Figure 4 4 Figure 4 5 Figure 4 6 Figure 4 7 Figure 4 8 Figure 4 9 Figure 4 10 Figure 4 11 Figure 4 12 Figure 4 13 Figure 4 14 Figure 4 15 Figure 6 1 Figure 6 2 Figure 6 3 Figure 7 1 Figure 7 2 Figure 7 3 Figure 10 1 Figure 10 2 Figure 10 3 Figure 10 4 Figure 10 5 Figure 10 6 Figure 10 7 Figure 10 8 Figure 10 9 Figure 10 10 Table of Figures Major Components of The MSR Rotator System 17 TWO Styles Of Enclosure WindoW sise 19 Three Styles of Anchor PINS sccususissntsonsacessonsuadicwnaacersnssensssnsmaddndasdoadswnsrieennniennesess 19 Control Unit Front and Back PROMOS a ae rss mu 21 MOTO Unit C GR DOI ON sesrririsrisrrasn i narh r iEn an E EET ainin 23 Typical Rotating Disk Electrode RDE Tip with Shaft escscsccecrceesrrrrrerrers 24 Typical Rotating Ring Disk Electrode RRDE Tip with Shaft eee 25 Contact Areas at Top of Rotating Electrode Shaffs 3 The Brush Chamber side view cccodsrasccwdssaceasessaicaveasnascoossaboaseseaacesedpa
67. des a shaft suitable for use as a target Alternately a stainless steel rod 1 4 OD x 5 L 6 35 mm OD x 100 mm L may be mounted in the motor coupling and a mark can be made on the rod with a marker The calibration process involves making adjustments fo various trimmer potentiometers trimmers on the circuit board The MSR Calibration Kit includes a trimmer adjustment tool for this purpose Alternately a small flathead screwdriver can be used to make these adjustments A calibrated digital voltmeter is required fo confirm certain signal levels on the circuit board It is recommended that a 4 2 digit voltmeter be used for this purpose The calibration process also requires a known voltage source 1000 mV This known source can be a power supply or waveform generator and the value of the known voltage 1000 mV should be verified using the calibrated digital voltmeter Other tools required are a medium sized Phillips screwdriver fo remove the top panel of the control unit and a small 5 64 hex key fo turn the hex screws on the motor coupling when installing or removing a shaft The hex key is included with the purchase of a new rotator and it is also available at many retail hardware supply stores FINE RESEARCH INSTRUMENTATION DRU10002 REV 002 APR 2015 92 HIGH VOLTAGE HAUTE TENSION DANGER High voltage Risk of electric shock This procedure must be performed by an electrician or a qualified techn
68. djective used to describe a molecule ion or process associated with an electrochemical reaction Addition of electrons fo an ion or molecule A reference electrode has a stable and well known thermodynamic potential The high stability of the electrode potential is usually reached by employing a redox system with constant buffered or saturated concentrations of the ions or molecules involved in the redox half reaction In fluid mechanics the Reynolds number is a dimensionless number that gives a measure of the ratio of inertial forces to viscous forces and consequently quantifies the relative importance of these two types of forces for given flow conditions Rotation Rate Shielding Experiment Stagnant Layer Standard Electrode Potential Sweep Rate Three Electrode Cell Transit Time Turbulent Flow Voltammogram 149 The rate at which a rotating electrode rotates Experimentally this is usually expressed in RPM but in theoretical equations the rotation rate is usually expressed in radians per second An experiment with a rotating ring disk electrode where the disk potential is held constant while the ring potential is swept slowly between two limits At a rotating electrode the portion of the solution near the electrode fends fo rotate at nearly the same speed as the electrode surface This layer of solution is Known as the stagnant layer or in the context of fluid dynamics the stagnant layer is
69. dynamically modulated voltammetry The rotator is able to accurately follow complex waveforms and create the desired rotation rate response by using a high rate low inertia permanent magnet DC motor in combination with a high voltage bi polar power supply In general the MSR rotator can track and follow low frequency less than 100 Hz external input signals with amplitudes that do not exceed 10 of the baseline rotation rate The usual proportionality between the external input signal and the rotation rate is 1 0 RPM mV but a hardware jumper setting inside the control unit may be used to select the different ratios see Section 6 7 The rotation rate is typically monitored by observing the front panel display on the control unit In addition the tachometer measurement can be monitored by connecting an oscilloscope voltmeter or other recording device across the two output banana jacks on the front panel The volfage signal from the tachometer presented at these output jacks is proportional fo the rotation rate The ratio used for this signal is 1 0 mV RPM The control unit is connected to the motor unit using a 15 conductor cable with straight thru wiring terminated on each end with HD 15 connectors The usual cable length is 183 cm 72 in but longer distances can be spanned by chaining together multiple cables FINE RESEARCH INSTRUMENTATION 3 15 The motor unit can be positioned vertically along a center post that is m
70. e en provoquant l infiltration de liquides dans le joint situ entre l arbre et l embout d lectrode CAUTION Center the rotating electrode within the opening on the cell so that it does not rub against the walls of the opening Damage will occur if the rotating shaft or tip abrades against these walls ATTENTION Centrez l lectrode rotative dans l ouverture de la cellule pour qu elle ne frotte pas les bords de l ouverture Le frottement des bords de la cellule par l arbre ou par l embout d lectrode entrainera des dommages DRU10002 REV 002 APR 201 62 i TEMPERATURE LIMITATIONS Electrode tips with Teflon shrouds are designed for use at room temperature 15 C to 30 C Exposing these tips to colder or warmer temperatures is likely to compromise the seal between the Teflon shroud and the electrode surface Electrode tips with PEEK or KEL F shrouds are available and are better suited for use at elevated temperatures Note After each use of rotating electrode or electrode tip clean and dry the electrode and then return it to the plastic storage box in which it was originally shipped Note A polishing kit is available for use in restoring the electrode surface to its original mirror smooth finish A slurry of microscopic abrasive particles may be used to routinely repolish the electrode surface usually at the end of each day In the event of very serious damage to the electrode surface
71. e operating temperature range DRU10002 REV 002 APR 20 76 5 7 12 mm OD RCE Tips Legacy users of 12 mm RCE systems are encouraged to begin working with the newer 15 mm RCE geometry however the 12 mm geometry remains available 12 mm OD RCE Tips Legacy 12 mm OD RCE Tips accept cylinder inserts 12 mm OD x 7 96 mm fall fabricated from carbon or stainless steel Other materials are available on request The 12 mm OD RCE tios fit on fo a standard RCE RDE shaft part number AFE3M Contact Pine for details CAUTION Maximum Rotation Rate 2000 RPM Do not rotate at rates higher than the maximum rotation rate ATTENTION Vitesse de rotation maximum 2000 TR MIN Ne mettez pas l appareil en rotation a des vitesses sup rieures la vitesse de rotation maximum i OPERATING TEMPERATURE RANGE 15 C to 25 C Do not use this electrode outside the operating temperature range 77 6 1 Routine Cleaning Regular maintenance of the rotator primarily consists of keeping the external surfaces of the system clean by wiping them with a towel moistened with water or a mild non abrasive cleaner After about two weeks of continuous use open the brush chamber and vacuum out any dust or debris If necessary remove the lower bearing assembly for better access to the brush chamber see section 6 3 and use a towel moistened with water or a mild non abrasive cleaner to clean the inner surfaces of the brush chamber
72. ee e e JINE DRU10002 REV 002 APR 2015 100 Rotation _ Rotator Model and Serial Number Technician sign and date here Rate Ca libration Tachometer Make Model and SN Tachometer Calibration Date Record So Voltmeter Make Model and SN Voltmeter Calibration Date Control Unit Display and Output Signal Calibration Display Reading RPM RPM volts o w o o S o O w ES PS S O w o w ES Control Unit Input Signal Calibration volts RPM RPM Display Reading C owo Steno 0x0 l w S ES ow w S S T a EE Note Above 200 RPM rotation rate is certified to be within 1 0 of the value on the control unit display From 100 to 200 RPM the rate is certified to be within 2 counts of the displayed rate Note The control unit and motor unit must be calibrated together as a system This certification is valid only for the particular motor and control units with the serial number listed above 101 6 7 Changing the Input Rotation Rate Ratio The rotation rate can be controlled by applying an external voltage signal to the input jacks on the front panel of the control unit The proportionality ratio used to convert the applied voltage signal to the rotation rate can be set to one of three different values 1 0 2 0 or 4 0 RPM mvV Normally the value for the rotation rate ratio is selected to match the control signal provided by a particular potentiostat When shipped from the factory the MSR rotator is pre config
73. einstall the board in the control unit and secure the board to the front panel At this point the input ratio has been changed Make a note in a log book or place a sticker on the control unit to indicate the new input ratio 6 8 Changing the Motor Stop Signal Logic The motor stop signal on the back panel of the control unit is a digital signal that can be used fo bring the motor to a complete stop This digital signal can be configured for either active HIGH or active LOW logic The motor stop signal usually originates from a potentiostat that is controlling the rotator A cable from the potentiostat applies the signal to the Motor Stop banana jack blue on the back panel This signal is a TTL fype digital logic signal with a voltage level that is measured versus the DC Common i e any of the black banana jacks on either the front or back panel If The motor stop signal logic is configured for active HIGH logic the behavior is as follows The motor is allowed to rotate if a signal greater than 2 0 volts is applied to the blue Motor Stop banana jack The motor is stopped if the Motor Stop signal is driven to DC Common i e it stops if the blue Motor Stop banana jack is shorted to any of the black DC Common jacks DRU10002 REV 002 APR 2015 104 Note C When the control unit is configured for active HIGH logic and l when no connections are made to the motor stop banana jacks the motor is al
74. el of the control box The other end of the special cable is connected to the potentiostat The analog rate control signal from the potentiostat is a voltage that is proportional to the desired rotation rate The MSR rotator is factory configured to use a 1 0 RPM mV ratio which is the ratio compatible with Pine potentiostats Other ratios are available for use with other potentiostats see Section 6 7 h INE eee E RESEARCH INSTRUMENTATION N 57 External control of the rotation rate may involve a signal connection between a potentiostat from one manufacturer being connected to a rotator from another manufacturer The signals on these various instruments may have been calibrated to different tolerances by each manufacturer Small signal level differences within these tolerances can add up causing the actual rotation rate as displayed on the control unit to differ slightly from the specified rotation rate as entered by the user of the potentiostat software 4 7 4 External Motor Stop Control An external digital signal can be applied across the MOTOR STOP banana jacks on the back panel to bring the rotator to a complete stop see Figure 2 4 This digital signal can be used by a potentiostat or other external instrument to assure that the rotation rate is actually zero The logic for this digital signal may be either active HIGH or active LOW For the Pine MSR rotator the MOTOR STOP Is configured at the factor
75. electrochemical signals 53 Figure 4 13 Connect Potentiostat to Earth Ground on Control Box Front Panel If the potentiostat offers a chassis terminal connection often located on the back panel of the potentiostat then connecting this chassis terminal to the earth ground on the rotator control box may or may not reduce or eliminate noise in the measured electrochemical signals For a potentiostat with a chassis that normally floats with resoect to earth ground the chassis will no longer be floating after making this direct connection to earth ground Note C The chassis terminal on the back panel of the Pine WaveDriver 10 and WaveDriver 20 potentiostats normally floats with respect to the earth ground If the potentiostat chassis is connected to the earth ground on the front panel of the rotator control unit the potentiostat no longer floats with respect to earth ground lf the potentiostat does not offer a chassis terminal connection or if earth grounding the chassis terminal is not an option then a less desirable but alternative approach is to attempt to make use of the potentiostat s signal ground DC Common If the DC Common often provided as an alligator clip connection on the cell cable is connected to the earth ground on the rotator control box this may or may not reduce or eliminate signal noise In general in an electrochemical experiment if is always ideal to maintain as much i
76. ential is sufficiently positive relative to the standard electrode potential At this point any of the reduced form R that reaches the electrode surface is immediately converted to the oxidized form O R O ne The observed current is the result of electrons flowing into the electrode The maximum current observed is called the anodic limiting current iLa FINE RESEARCH INSTRUMENTATION 5 DRU 10002 REV 002 APR 2015 126 anodic mass transport limited current ita anodic current Potential mV vs E cathodic current 0 10 20 0 10 20 Time sec Time sec Figure 10 2 Response to a Potential Sweep Anodic from a Solution Initially Containing only the Reduced Form R with no Oxidized Form O 10 3 1 Voltammogram Plotting Conventions The two streams of data recorded during a voltammetry experiment are the potential vs time and the current vs time Rather than plot these two streams separately as shown in Figure 10 3 left it is more common to plot current vs potential as shown in Figure 10 3 right Such a plot is called a voltammogram Although most electroanalytical researchers agree that current should be plotted along the vertical axis and potential should be plotted along the horizontal axis there is not widespread agreement as to the orientation direction for each axis Some researchers plot positive anodic oxidizing potentials toward the right while others pl
77. eriments When a molecule or ion is oxidized or reduced at an electrode it is often transformed into an unstable intermediate chemical species which in turn is likely to undergo additional chemical changes The intermediate may have a long enough lifetime that it is capable of moving to the ring electrode and being detected Or the intermediate may be so unstable that it decays away JINE RESEARCH INSTRUMENTATION N DRU 10002 REV 002 APR 2015 138 before it can be detected at the ring Consider the following reaction scheme at a rotating ring disk electrode Atne X reduction of A to unstable intermediate X at disk electrode K 7 chemical decay of X to electrochemically inactive Z X A ne oxidation of X back to A at ring electrode In the above scheme the disk electrode is poised at a potential where A Is reduced to X and the cathodic limiting current observed at the disk ipisk is a measure of how much X Is being generated at the disk electrode At the same time the ring electrode is poised at a more positive potential where X is oxidized back to A and the anodic limiting current observed at the ring irinc is a measure of much X is being collected at the ring There is also a competing chemical reaction which is capable of eliminating X before if has a chance to travel from the disk fo the ring The ratio of the ring current to the disk current under these conditions is called the apparent collecti
78. f the molecule or ton is initially present 10 4 Rotating Disk Electrode RDE Theory The general theory describing the rotating disk electrode was originally developed by Dr Benjamin Levich in his landmark book called Physiochemical Hydrodynamics Prentice Hall In 1962 this book was translated from Russian to English and researchers in the United States and the United Kingdom rapidly built upon Dr Levich s seminal work Dr Stanley Bruckenstein s laboratory at the University of Minnesota and later at the University of Buffalo and Dr Dennis Johnson lowa State University applied rotating disk and ring disk electrodes fo many electroanalytical systems while Dr John Alberyl 2 71 and Dr Michael Hitchman both at Oxford University continued to expand the basic theory of rotating disk and ring disk electrodes Subsequent generations of researchers expanded on this initial work until the rotating disk electrode became a mature tool for probing electrochemical reaction kinetics The laminar tlow at a rotating disk electrode conveys a steady stream of material from the bulk solution to the electrode surface While the bulk solution far away from the electrode remains well stired by the convection induced by rotation the portion of the solution nearer to the electrode surface tends to rotate with the electrode Thus if the solution is viewed from the frame of reference of the rotating electrode surface then the solution appears relat
79. fel analysis The term cyclic voltammetry CV refers to a method where the electrode potential is swept repeatedly back and forth between two extremes When working with a rotating electrode if is common to further specify the kind of electrode being used as part of the technique name such as rotating disk voltammetry rotating ring disk voltammetry or rotating cylinder voltammetry In each of these techniques the rotation rate is held constant as the electrode Is swept from one potential to another potential at a constant sweep rate In electroanalytical chemistry the potential sweep usually soans at least 200 mV on either side of the standard electrode potential and rotation rates are usually between 100 RPM and 2400 RPM However in the context of a corrosion study the potential sweep may span a much narrower range 50 mV using a slower sweep rate less than 5 mV sec with an emphasis on higher rotation rates As an example consider a solution that initially contains only the oxidized form of a molecule or ion A rotating electrode is placed in this solution and is initially poised at a potential that is 200 mV more positive than the standard potential At this potential there is little or no current because there is nothing to oxidize the molecule or ion is already oxidized and the potential is not yet negative enough to cause any appreciable reduction of the molecule or ion Next the electrode potential is slowly 20 mV sec swep
80. g assembly is a common replacement item due to mechanical wear and also due fo exposure fo corrosive vapors from the cell solution The standard lower bearing assembly contains a stainless steel bearing which is generally resistant to corrosive attack In laboratories where particularly corrosive solutions are used an assembly based on a ceramic bearing can be used instead Part numbers for bearing assemblies are listed in Section 7 1 ERP RESEARCH INSTRUMENTATION F DRU 10002 REV 002 APR 2015 82 WARNING Rotating shaft Entanglement hazard Turn off the power to the rotator and disconnect the power cord from the power source before continuing with this procedure AVERTISSEMENT Arbre en rotation Danger d enchev trement Eteignez le rotateur et d branchez le cordon d alimentation de la source d alimentation avant de poursuivre cette proc dure Disconnect the motor control cable from the connector on top of the motor unit If there is a shaft presently installed the motor unit remove the shaft Disconnect any signal cables from the brush banana jacks red and blue Use a flathead screwdriver to loosen the four screws that secure the lower bearing assembly to the motor unit As you are loosening the final screw with one hand catch the bearing assembly with your other hand C Note i After the bearing assembly has been removed it is a good idea to y clean or vacuum out any debris in the brush ch
81. h to a person due fo a high speed rotating shaft DANGER LIE A LA ROTATION DE L ARBRE Indique les informations n cessaires a la prevention de blessures corporelles ou de mort d un individu cause de la vitesse lev e de rotation de l arbre RISK OF ELECTRICAL SHOCK Indicates information needed to prevent injury or death to a person due to electrical shock RISQUE DE DECHARGE ELECTRIQUE Indique les informations n cessaires la pr vention des blessures ou la mort d une personne cause d une d charge lectrique RISK FROM LASER LIGHT Indicates information needed to prevent eye injury due fo laser beam light RISQUE LIE A LA LUMIERE LASER Indique les informations n cessaires la prevention des dommages oculaires cause de la lumi re d un faisceau laser Table 1 3 Safety Warning Icons used in this Document Tableau 1 3 Ic nes d avertissement de s curit utilis es dans ce document CAUTION Indicates information needed to prevent damage to equipment ATTENTION Indique les informations n cessaires la pr vention des dommages aux quipements RISK OF ELECTROSTATIC DAMAGE Indicates information needed to prevent damage to equipment due fo electrostatic discharge RISQUE DE DOMMAGES ELECTROSTATIQUES Indique les informations n cessaires la pr vention des dommages l quipement cause d une d charge lectrostatique CHEMICAL INCOMPATIBILTY Indicates
82. haft or before installing or removing an electrode tip on the end of the shaft AVERTISSEMENT Arbre en rotation Danger d enchev trement teignez le rotateur et d branchez le cordon d alimentation de la source d alimentation avant d installer ou d enlever l arbre de l lectrode ou avant d installer ou d enlever un embout d lectrode l extr mit de arbre WARNING Do not use or attempt to rotate an electrode shaft that has been dropped bent or otherwise physically damaged Inspect the shaft to be certain that it is not damaged AVERTISSEMENT N utilisez pas et ne tentez pas de mettre en rotation un arbre d lectrode qui est tomb a t tordu ou a t endommag physiquement d une autre mani re ou d une autre Inspectez l arbre pour vous assurer qu il n a pas t endommag WARNING Do not use an electrode shaft which appears to wobble vibrate or tilt away from the axis of rotation while rotating Such a shaft is either improperly installed or physically damaged Turn off the rotator disconnect electrical power and remove the shaft immediately AVERTISSEMENT N utilisez pas un arbre d lectrode qui semble osciller vibrer ou d vier de l axe de rotation pendant la rotation Cet arbre est soit install de mani re incorrecte soit endommag physiquement teignez le rofateur d connectez l alimentation lectrique et retirez l arbre imm diatement 39 WARNING Do not use or
83. hassis of the motor unit is in contact with the chassis of the control unit The chassis of the control unit is in turn in contact with earth ground via the third prong on the power cord thus the motor unit chassis is also earth grounded Note Some older rotator models did not have a shielded motor control cable These older unshielded motor control cables are easily recognized because they are permanently connected to the control unit If working with one of these older rotators it is necessary to purposefully make a connection from the motor unit chassis to the earth ground connection on the front panel of the rotator control box 4 5 3 A Typical Grounding Strategy While the details of proper grounding for any given electrochemical experiment may differ a common approach when working with a rotating electrode cell is to connect the chassis of all instruments involved in the experiment to the earth ground at a common point The earth ground connection on the front panel of the rotator control box serves as a convenient common point for such a strategy There are two important grounding connections that should be considered in any rotating electrode experiment The first important connection is fo ground any metal clamps or cell supports near the electrochemical cell see Figure 4 12 If left ungrounded these metal FINE RESEARCH INSTRUMENTATION N DRU10002 REV 002 APR 201 52 objects may act as
84. hat has been dropped bent or otherwise physically damaged Inspect the shaft to be certain that it is not damaged AVERTISSEMENT N utilisez pas et ne tentez pas de mettre en rotation un arbre d lectrode qui est tomb a t tordu ou a t endommag physiquement d une autre mani re ou d une autre Inspectez l arbre pour vous assurer qu il n a pas t endommag Tip It is often easier to remove or install a shaft disconnecting the motor control cable and inverting the entire motor unit on the center post Several of the photos in this section of the manual show the rotator motor in such an inverted position Tip iy Do not lose the white plastic washer on the door latch DRU10002 REV 002 APR 201 34 Invert the orientation of the motor unit so that it is upside down as shown Loosen the latch on the clamshell doors Open the doors to provide access to the brush chamber If there is a shaft already installed use the hex driver tool 5 64 provided to loosen the two screws on the motor coupling Do not remove these screws entirely just loosen them by one or two turns of the hex driver Usually if is necessary to hold the motor coupling in place with one hand while loosening the screws with the other hand Note GC l A new rotator has tape around the motor coupling to protect the hex screws Remove this tape and loosen the hex screws if needed to allow the shaft to enter the coupling
85. he cowling from the motor unit The internal cable assembly will prevent the cowling from being completely removed However there is a junction in the middle of the infernal cable assembly where two white connectors are joined together By disconnecting the cable assembly at this junction if is possible to remove the cowling completely Disconnect the junction by releasing the locking mechanism that holds the connectors together 85 The internal cables are secured to the motor using two plastic cable ties In order to remove the motor the lower cable tle must be cut and removed CAUTION DO NOT REMOVE the upper cable tie The upper cable tie protects the fragile motor connections ATTENTION NE RETIREZ PAS l attache de c ble sup rieure L attache de c ble sup rieure prot ge les c bles fragiles de connexion au moteur Note The red positive and black negative lines are connected to the tachometer and the white positive and green negative lines are connected to the motor DRU10002 REV 002 APR 2015 86 There are four screws which hold the motor in place Using a flathead screwdriver loosen and remove these four screws As the fourth and final screw is being removed be sure to support the motor and brush chamber from below to prevent damage from a sudden fall Carefully lower the motor out of the support while guiding the fragile motor and tachometer cables through the support
86. he ring but the species Y is active By carefully poising the ring electrode at a potential appropriate for detecting Y in this case by oxidizing Y to B it is possible for the ring to collect any Y which arrives at the surface of the ring The ratio of the ring current due to Y being detected at the ring to the disk current due to X being generated at the disk reveals the extent to which the X Y pathway is favored in comparison to the X Z pathway The fraction of the decay by the X Y pathway Oxy can be computed as follows n Ce Ny Note in the above equation that the fraction n n2 carefully accounts for any difference in the number of electrons involved in the disk half reaction and the FINE RESEARCH INSTRUMENTATION 5 l RING l DISK DRU 10002 REV 002 APR 2015 140 number of electrons involved when detecting Y at the ring electrode Schemes involving more complex stoichiometry may require additional correction factors The most commonly studied reaction at the RRDE is undoubtedly the oxygen reduction reaction ORR 243 4 When oxygen O2 is dissolved in acidic media and reduced at a platinum electrode one pathway leads to water as the ultimate reduction product while the other pathway leads to the formation of peroxide anions In the context of hydrogen fuel cell research the pathway which leads to water is preferred and it is commonly called the four electron pathway The path to per
87. held tachometer E7 4 v 5 kon 7 b Figure 6 3 Use of Optical Tachometer with Reflective Target nn INSTRUMENTATION j 91 6 6 Rotation Rate Calibration The rotation rate is controlled by a tunable analog feedback circuit located inside the control unit This circuit is tuned and calibrated at the factory prior to shipment but if the rotator needs to be recalibrated by the owner at a later date the procedure below describes the best method for calibrating and verifying the rotation rate control circuit The most important tool required for calibrating the rotator is a non contact optical tachometer Pine offers such a simple tachometer see Figure 6 1 as part of the MSR Calibration Kit and this simple tachometer is suitable for routine verification or calibration of the rotation rate by the owner The MSR Calibration Kit is sold separately see Section 7 1 for part number In the event that the rotation rate must be rigorously traceable to a national or international standards organization a more sophisticated and professional tachometer with traceable certification should be used see Figure 6 2 When a rotator is manufactured at the factory or when a rotator is returned fo the factory for service recalibration is performed using a traceable tachometer The tachometer reads the rotation rate when if is pointed at a rotating shaft equipped with a reflective target see Figure 6 3 The MSR Calibration Kit inclu
88. hould be connected to the reference electrode The outer shield line should not be connected to anything at the cell end of the cable Do not ground such a driven shield line as if may cause the potentiostat to oscillate or malfunction DRU10002 REV 002 APR 201 5 120 9 Storage and Shipment In the event that the rotator system is not going to be used for a long period of time if should be stored in the original packaging material to prevent damage It should be stored at temperatures between 17 C and 37 C and at humidity levels less than 95 non condensing Retain the original packing materials for future use These packing materials were designed to provide both protection in shipment and fo minimum size and weight for efficient shipment 121 10 Theory 10 1 Forced Convection The current signal recorded during an electrochemical experiment is easily influenced or disturbed by the convection of various molecules and ions due fo bulk movement of the solution Proper interoretation of the current signal must accurately account for any contributions desired or undesired from solution convection Thus the control of solution movement is a critical part of any electrochemical experiment design and the issue of convection cannot be ignored Two opposing approaches are typically used fo address the convection issue At one extreme an experiment can be conducted in a quiescent solution so that convection
89. ician This procedure requires working inside the control unit while the control unit is powered on and operating High voltages are present inside the control unit at the power entry module and on the two internal power supply modules as shown in the shaded and outlined portion of the image below KEEP HANDS AND TOOLS AWAY FROM THE POWER ENTRY MODULE AND THE TWO POWER SUPPLY MODULES DANGER Haute Tension Risque de d charge lectrique Cette proc dure doit tre confi es un lectricien ou un technicien qualifi Cette proc dure requiert de travailler l int rieur de l unit de commande lorsque cette derni re est aliment e et en fonctionnement Des tensions lev es sont pr sentes dans l unit de commande au niveau du module d entr e d alimentation et sur les deux modules d alimentation internes tel qu indiqu dans la portion gris e et mise en vidence de l image ci dessous GARDEZ VOS MAINS ET VOS OUTILS LOIGN S DU MODULE D ENTR E D ALIMENTATION ET DES DEUX MODULES D ALIMENTATION 93 CAUTION Static electricity may damage electronic components Ensure proper grounding when handling static sensitive components by wearing a grounding strap ATTENTION L lectricit statique est susceptible d endommager les composants lectriques Veillez disposer d une mise la terre appropri e lorsque vous manipulez des composants sensibles en portant un ruban de mise la terre Note
90. iment is typically only on a particular half reaction occurring at the working electrode Declaration of Conformity The Manufacturer of the Products covered by this Declaration is Pine Electronics LLC 101 Industrial Drive Grove City PA 16127 USA Phone 724 458 6391 Fax 724 458 4648 The Directives covered by this Declaration are EMC Directive 2004 108 EC EC Low Voltage Directive The Products Covered by this Declaration are AFMSRCE AFMSRwxyz where wxyz describe minor cosmetic variations Analytical Rotators The Basis on which Conformity is being declared The manufacturer hereby declares under his sole responsibility that the products identified above comply with the above noted directives and that the following standards have been applied EN 61326 1 2013 Emissions Requirements EN 61326 1 2013 Immunity Requirements IEC61010 2 201 2013 Safety Requirements IEC61010 1 2010 Corrigendum 1 2011 Safety Requirements The technical documentation required to demonstrate that the products meet the requirements of the directives has been compiled and is available for inspection by the relevant enforcement authorities The CE mark was applied per the following reports Keystone Compliance 1407 062E Intertek 101822526COL 001 Signed TARA Le Authority Vice President of Engineering Date February 12 2015
91. increases with increasing rotation rate Experiments involving a rotating electrode are designed to purposefully exploit this fundamental relationship between the rotation rate and the limiting current 200 100 anodic current cathodic mass transport limited current Ic 100 Potential mV vs E cathodic current 200 0 10 20 0 10 20 Time sec Time sec Figure 10 1 Response to a Potential Sweep Cathodic from a Solution Initially Containing only the Oxidized Form O with no Reduced Form R The cathodic sweep experiment described above see Figure 10 1 applies to the case where the solution initially contains only the oxidized form O of the molecule or ion being studied The opposite case yields similar results Consider a solution that initially contains only the reduced form R of the molecule or ion being studied The rotating electrode is initially poised at a potential that is about 200 mV more negative than the standard potential At this potential there Is little or no current because there is nothing to reduce the molecule or ion is already reduced and the potential is not yet positive enough to cause any appreciable oxidation of the molecule or ion Next the electrode potential is slowly swept in the positive anodic direction see Figure 10 2 left and an anodic current is observed see Figure 10 2 right The anodic current eventually reaches a maximum value when the pot
92. information found in this document Des ic nes sp ciales voir tableau 1 2 1 3 et 1 4 sont utilis es pour attirer l attention sur des avertissements de s curit et autres renseignements utiles disponibles dans ce document STOP For a procedure involving User action or activity this icon indicates a point in the procedure where the user must stop the procedure ARR T Dans une op ration impliquant l action ou l activit d un Utilisateur cette ic ne indique une partie de l op ration o l utilisateur doit arr ter l op ration Note Important or supplemental information Remarque Renseignements importants ou compl mentaires Tip Useful hint or advice Conseil Astuce ou conseil utile Wait Time Describes an operation or process which requires an unusually long time fo complete Temps d attente D crit une op ration OU Un processus prenant un temps anormalement long s effectuer Table 1 2 Special Icons Used in this Document Tableau 1 2 Ic nes sp ciales utilis es dans ce document DRU10002 REV 002 APR 2015 WARNING Indicates information needed to prevent injury or death to a person or to prevent damage to equipment ATTENTION Indique les informations n cessaires a la prevention de blessures corporelles ou de mort d un individu ou la pr vention des dommages aux quipements ROTATING SHAFT HAZARD Indicates information needed to prevent injury or deat
93. isk 12 MM OD shroud oo eeeeeeeeeeeeeeeeeeees AFE2MOSOAL Copper FasiSpeed RDE 5 mm OD disk 12 MM OD shroud ce eeeeeeeeeessnneeeeeeees AFE2MOSOCU Gold FastSpeed RDE 5 mm OD disk 12 MM OD shroud eee eeeeeeeeeeeeeeeeeeeeeeees AFE2MO50AU Nickel FastSpeed RDE 5 mm OD disk 12 MM OD shroud eeeeeeeeceeeeteteteeeeees AFE2MO50NI Palladium FastSpeed RDE 5 mm OD disk 12 MM OD shroud cee eeeeeeeeeeceeeceeeeeeeeees AFE2MOSOPD Platinum FastSpeed RDE 5 mm OD disk 12 MM OD shroud ke eeeesseeeeeeeceeeeeeeeeeeees AFE2MO50PT Silver FastSoeed RDE 5 mm OD disk 12 MM OD shroud cc ccccccccssseseseseeeeeeeees AFE2MOSCAG Tantalum FastSpeed RDE 5 mm OD disk 12 MM OD Shroud eee eeeeeseeeeeeeeeeeeeeeeees AFE2MOSOTA Titanium FastSpeed RDE 5 mm OD disk 12 MM OD shroud AFE2MOSOTI Tungsten FastSpeed RDE 5 mm OD disk 12 MM OD shroud ee eeeesseeeeeeeeeceseeeeeeees AFE2MO50W Zinc FastSpeed RDE 5 mm OD disk 12 MM OD shroud ue AFE2MOSOZN CAUTION A Maximum Rotation Rate 7000 RPM Do not rotate at rates higher than the maximum rotation rate ATTENTION Vitesse de rotation maximum 7000 TR MIN Ne mettez pas l appareil en rotation a des vitesses sup rieures a la vitesse de rotation maximum ane WARNING A Rotating shaft Use extreme caution when operating the rotator at rotation rates above 2000 RPM Always secure the enclosure around the rotator before rotating the electrode see Figure 4 6 AVERTISSEMENT Arbre en rotation Soyez extr
94. it chassis Earth Ground and the motor unit chassis via the motor control cable is also connected to earth ground via the power cable third prong 4 Reset Button Motor circuit breaker reset DC Common DC signal common isolated from chassis External control of the rotation rate is Rotation Rate possible by applying a voltage signal across Input Signal these banana jacks see Section 4 7 3 1 2 or 4 RPM mV ratio 50KQ impedance ON A voltage signal proportional to the rotation rate is presented at these banana jacks 1 0 mV RPM 600 Q output impedance 8 Control Box Cover Metal cover Rotation Rate Output Signal 9 Control Box Cover Screws Metal screws that hold cover on control unit This digital logic signal is used to stop 20 Motor Stop Input Signal electrode rotation see Section 4 7 4 Nationally Recognized Testing Laboratory 21 NRTL Mark compliance label ETL Mark from Intertek 2 Motor Cable Connector Accepts one end of motor control cable 23 Serial Number Plate Unigue system serial number 4 Power Cord Connector Connects to external electrical power cord 25 Power Switch Main power switch with circuit breaker Ce De Es 21 INE ROTATING ELECTRODE e SPEED CONTROL N INPUT OUTPUT 1 mV per RPM RESET Ls PINE Durham NC www prneinst com echem MOTOR STOP MODEL AFMSRCE Serial No as Figure 2 4 Control Unit Front and B
95. it includes a dial indicator used to measure the runout at the end of the shaft see Section 7 1 for kit part number 37 WARNING Do not use an electrode shaft which appears to wobble vibrate or tilt away from the axis of rotation while rotating Such a shaft is either improperly installed or physically damaged Turn off the rotator disconnect electrical power and remove the shaft immediately AVERTISSEMENT N utilisez pas un arbre d lectrode qui semble osciller vibrer ou d vier de l axe de rotation pendant la rotation Cet arbre est soit install de mani re incorrecte soit endommag physiquement teignez le rotateur d connectez l alimentation lectrique et retirez l arbre imm diatement If the shaft is rotating properly along the axis of rotation then if is ready for use Some shafts are actually single piece electrodes where the electrode tip is permanently attached to the shaft But most shafts are designed to accept a variety of different tips For these shaft and tip designs the shaft may remain mounted in the rotator and changing the Tip Is a simple matter of unscrewing one tip and then threading a new tip on fo the shaft DRU10002 REV 002 APR 2015 38 4 1 2 Changing the Tip on a Shaft A WARNING Rotating shaft Entanglement hazard Turn off the power to the rotator and disconnect the power cord from the power source before installing or removing the electrode s
96. it is generally better to return the electrode to the factory for professional repolishing 63 5 2 Shafts The rotator accepts a variety of different shaft designs each sold separately having a sturdy metal internal shank that is insulated with a polymeric shroud The upper portion of the shaft is designed to mate with the motor coupling inside the brush chamber see Figure 4 2 The lower portion of the shaft is protected with a chemically resistant shroud material Teflon PEEK or KEL F Standard RDE amp RCE Shaft 12 mm OD The lower end of this shaft features a 12 0 mm OD Teflon shroud and a standard 1 4 28 thread These threads accept RDE and RCE tios with 12 0 mm OD shrouds Specifically this shaft is compatible with E3 amp EATQ Series RDE Tips and with classic 12 mm OD rotating cylinder electrode fips A bearing assembly for mounting this shaft in a 24 25 ground glass joint is available separately Description Part Number SICNAGIA RDE amp RCE Sait Or IZ WAM OD OS a ac ane sn AFE3M Bearing Assembly 24 25 taper for Standard RDE amp RCE Shaft eee cccccceeeeeeeeeeeeenes ACOITPA Precision RDE amp RRDE Shaft 15 mm OD for use with gas purged bearing assembly This shaft has a precision machined 15 0 mm outer diameter which is specially designed to mate with the 15 0 mm inner diameter of a gas purged bearing assembly This shaft is compatible with E5 E5TQ ESHIT E E6R2 amp E7 Series Tips
97. ively stagnant This relatively stagnant layer is known as the hydrodynamic boundary layer and its thickness 64 can be approximated 5 3 6 v 60 in terms of the kinematic viscosity of the solution v and the angular rotation rate w 2 x f 60 where fis the rotation rate in revolutions per minute In an aqueous solution at a moderate rotation rate 1000 RPM the stagnant layer is approximately 300 to 400 um thick Net movement of material to the electrode surface can be described mathematically by applying general convection diffusion concepts from fluid dynamics Mass transport of material from the bulk solution into the stagnant layer occurs by convection due to the stirring action of the rotating electrode But after the material enters the stagnant layer and moves closer to the electrode surface convection becomes less important and diffusion becomes more important Indeed the final movement of an ion or molecule to the electrode surface is dominated by diffusion across a very thin layer of solution immediately adjacent to the electrode known as the diffusion layer FINE RESEARCH INSTRUMENTATION 5 131 The diffusion layer is much thinner than the hydrodynamic layer The diffusion layer thickness r can be approximated as follows 6 l61D vo in terms of the diffusion coefficient Dr of the molecule or ion For a molecule or ion with a typical diffusion coefficient Dr 10 cm2 sec in an aqueous solution
98. lectrode materials used to fabricate rotating disk and ring disk electrodes are gold platinum and glassy carbon Rotating cylinder electrodes are usually made from various alloys of steel aluminum or brass 147 Faradaic Current Forced Convection Half Reaction Hydrodynamic Layer Hydrodynamic Voltammetry Insulating Materials Laminar Flow Levich Equation Levich Study Levich Plot Linear Polarization Resistance The portion of the current observed in an electroanalytical experiment that can be attributed fo one or more redox processes occurring at an electrode surface Active stirring or pumping of a liquid solution A balanced chemical equation showing how various molecules or ions are being reduced or oxidized at an electrode surface see the definition of stagnant layer A family of electroanalytical methods based upon precise control of solution flow coupled with rigorous mathematical models Chemically resistant and electrically insulating polymers commonly used to fabricate rotating electrodes include Teflon PEEK poly ether ether ketone and KEL F Laminar flow sometimes known as streamline flow occurs when a fluid flows in parallel layers with no disruption between the layers The Levich equation describes the mass transfer limited current at a rotating disk electrode Experiment using a rotating disk electrode in which a series of voltammograms are acquired over a range of
99. linder surface tends to rotate with the electrode Thus a high shear condition is set up at the surface of the rotating cylinder spinning off smaller Taylor vortices adjacent to the rotating electrode Net movement of material to the surface of a rotating cylinder was first characterized by Eisenbergli amp T1 in 1954 about the same time that Levich was describing the rotating disk electrode Eisenberg s work eventually led to the Eisenberg equation which gives the limiting current at a rotating cylinder electrode i 0 0487 n F A di DT yp nee C ae 141 in terms of the concentration C and diffusion coefficient D of the molecule or ion being studied the Faraday constant F 96485 coulombs per mole the electrode area A the diameter of the cylinder dey the kinematic viscosity of the solution v and the angular rotation rate 2 m f 60 where f is the rotation rate in revolutions per minute In the years since Eisenberg s initial work with the rotating cylinder additional work by Gabe Kear Walsh and Silverman has described industrial applications of the RCE 8 25 55 60 10 7 References l 10 S Treimer A Tanga and DC Johnson Consideration of the Application of Koutecky Levich 11 12 13 17 FINE RESEARCH INSTRUMENTATION 5 PT Kissinger and WR Heineman Laboratory techniques in electroanalytical chemistry Marcel Dekker New York 1996 AJ Bard and LR Faulkner Electrochemical Methods
100. lisez pas un embout d lectrode qui semble osciller vibrer ou d vier de l axe de rotation pendant la rotation Cet embout d lectrode est soit install e de mani re incorrecte soit endommag e physiquement teignez le rotateur d connectez l alimentation lectrique et retirez l embout d lectrode imm diatement 13 WARNING Laser radiation Many optical tachometers use a laser beam as a light source Do not look directly at the laser beam Do not point the laser beam into the eye AVERTISSEMENT Rayonnement laser Un grand nombre de tachym tres optiques utilisent un faisceau laser comme source de lumi re Ne regardez pas directement le faisceau laser Ne pointez pas le faisceau laser dans l il CAUTION When raising or lowering the motor unit along the main support rod be sure to hold the motor unit carefully so that it does not unexpectedly fall and break the glass cell located below the motor unit ATTENTION Lorsque vous montez ou descendez le bloc moteur le long de la barre principale veillez a bien le tenir pour viter qu il ne chute brutalement et ne casse la cellule de verre situ e sous le bloc moteur CAUTION A detachable main power cord is provided with the rotator Do not replace this cord with an inadequately rated cord ATTENTION Un cordon d alimentation amovible est fourni avec le rotateur Ne remplace pas ce cordon par un cordon de calibre inad quat DRU10002 R
101. ll with multiple side ports carefully orient the cell so that any accessories mounted in the side ports have enough clearance Smaller cells may be clamped using a traditional laboratory clamp secured to the center port see Figure 4 5 left Larger cells may be clamped using a large diameter column clamp see Figure 4 5 right The cell platform and clamp positions allow adjustment of the vertical position of the cell with respect to the motor unit In addition the vertical position of the motor unit is easily adjusted Usually if is easier fo mount and clamp the cell in a fixed vertical position Then the rotating electrode can be moved vertically down into the cell or up out of the cell as needed CAUTION A When raising or lowering the motor unit along the main support rod be sure to hold the motor unit carefully so that it does not unexpectedly fall and break the glass cell located below the motor unit ATTENTION Lorsque vous montez ou descendez le bloc moteur le long de la barre principale veillez a bien le tenir pour viter qu il ne chute brutalement et ne casse la cellule de verre situ e sous le bloc moteur CAUTION A Position the motor unit with respect to the glass cell so that the us electrode tip is immersed approximately 1 0 cm into the test solution Excessive immersion may corrode the shaft or tip by allowing liquids to seep into the joint between the shaft and tip ATTENTION Positionnez le bloc mo
102. lowed to rotate An internal pull up circuit assures that the motor stop signal remains high in this case If the motor stop signal logic is configured for active LOW logic the behavior is as follows The motor is stopped if a signal greater than 2 0 volts is applied to the blue Motor Stop banana jack The motor is allowed to rotate if the Motor Stop signal is driven to DC Common i e if rotates if the blue Motor Stop banana jack is shorted to any of the black DC Common jacks Normally the choice for the Motor Stop signal logic is selected to match the control signal provided by a particular potentiostat When shipped from the factory the MSR rotator is pre configured with active HIGH logic because this logic is compatible with Pine potentiostat systems WARNING Risk of electric shock Disconnect all power before servicing the rotator AVERTISSEMENT Risque de d charge lectrique D connectez toutes les sources d alimentation avant de proc der l entretien du rotateur CAUTION Static electricity may damage electronic components Ensure proper grounding when handling static sensitive components by wearing a grounding strap ATTENTION L lectricit statique est susceptible d endommager les composants lectriques Veillez disposer d une mise la terre appropri e lorsque vous manipulez des composants sensibles en portant un ruban de mise la terre 105 With the p
103. m the voltage source should be connected to the INPUT signal jack gray banana jack and the negative lead from the voltage source should be connected to the DC Common black banana jack JINE RESEARCH INSTRUMENTATION 3 97 Determine the setting for the input rotation rate ratio 1 2 or 4 RPM mvV by carefully examining the position of jumper JP2 on the circuit board ag t t 1 RPM mV 2 RPM mV 4 RPM mV o Note Some older control units may not have jumper JP2 on the Circuit board In this case the input rotation rate ratio is printed on the front panel near the INPUT banana jacks Using the DC voltage source apply 1 000 VDC 0 001 VDC to the rotation rate INPUT signal and observe the reading on the front panel display The proper reading will depend upon the position of jumper JP2 as follows If JP2 is set for 1 RPM mV the display should read 1000 RPM 1 RPM lf JP2 is set for 2 RPM mV the display should read 2000 RPM 1 RPM lf JP2 is set for 4 RPM mV the display should read 4000 RPM 1 RPM Adjust P5 until the rotation rate display on the front panel is within the 1 RPM tolerance The optical tachometer should also indicate a rotation rate within this tolerance Disconnect the volfage source from the INPUT jacks on the front panel Verify the calibration at the several different rotation rates suggested rates are 200 500 1000 2000 and 5000 RPM At each rotation rate the rotation rate display on
104. mement prudent lorsque vous utilisez le rotateur des vitesses de rotation sup rieures 2000 tr min Fixez correctement le bo tier autour du rotateur du rotateur avant de mettre l lectrode en rotation voir figure 4 6 i OPERATING TEMPERATURE RANGE 15 C to 25 C Do not use this electrode outside the operating temperature range 72 5 5 RRDE Tips All RRDE tips have 15 mm OD shrouds made from either Teflon or PEEK The ring electrode is permanently mounted in the RRDE tip but the disk electrode may be permanently mounted or removable E6 Series ChangeDisk RRDE Tips These ring disk electrode tips feature a Teflon shroud and the option to remove and replace the disk insert These fips fit the standard RRDE shaft and may be used at rotation rates up fo 3000 RPM Standard disk and ring materials include gold platinum and glassy carbon Other materials are available Upon request Description Part Number Precision RDE amp RRDE Shaft for 15 mm OBS ea ee AFE6MB Toolkit for removing and polishing disk inserfs AFE6K050 ChangeDisk RRDE Tip platinum ring accepts 5 mm OD x 4mm thick disks n AFE6RIPT ChangeDisk RRDE Tip gold ring accepts 5 mm OD x 4mm thick disks ee eeeeeeeees AFE6R1 AU ChangeDisk RRDE Tip glassy carbon ring accepts 5 mm OD x 4mm thick disks AFE6RIGC Glassy Carbon Disk Insert 5 mm OD x 4 MM fhICkKJ eeeeeeseeeeeeeeeeeeecseeeeeeeees AFEDOSOP040GC Basal Plane
105. metal chassis of the instrumentation potentiostat and rotator the clamps and supports used to physically secure the electrochemical cell and any peripheral equipment heaters stirrers etc Used in conjunction with the measurement 4 5 1 Terminology Note 1 When working with electrochemical equipment it is important to understand the meanings of terms such as earth ground chassis terminal and DC common An earth ground connection is available in most modern laboratories via the third prong on the power receptacle for the local power system The power system infrastructure for a laboratory building usually has a long metal probe buried in the earth and the third prong in the building wiring is connected to this earth connection A chassis terminal is a connection to the metal chassis surrounding an instrument Depending upon how the instrument is connected to other experimental apparatus a chassis terminal may or may not be connected to the earth ground In the context of an electrochemical experiment involving a rotating electrode the DC Common also Known as the signal ground or signal common is the zero voltage reference point used by the signal measurement or waveform generation circuitry in the potentiostat and the rotation control circuitry in the rotator The DC common may or may not be connected to the earth ground depending upon how the experimental apparatus is arranged and
106. mm OD x 4 mm thick esesssssssesssssssssssseecceeresesssssssssseeecceeeeesesssssssseee AFEDOSOPO40AU Nickel Disk Insert 5 MM OD x 4 MM NICK oo cecccccceeeessesesssssneeeeeeeeeeeeeeeeseseeeeeeeas AFEDOSOPO4ONI Palladium Disk Insert 5 mm OD x 4 MM fhiCK eeeeeeeeeeeeeeeeteeeseteetssssetseseeeeees AFEDOSOPO40PD Platinum Disk Insert 5 MM OD x 4 MM RICK eeesceteteteteeeteeeettestssttesessteeeeeees AFEDOSOPO40PT Silver Disk Insert 5 MMOD X4 ana PIRE an a a dre AFEDOSOPO40AG Tantalum Disk Insert 5 mm OD x4 MM thiCk sac esninzedaveonzcdesmszedaxveosacdescsozcdaxveonedeaeenactas AFEDOSOPO40TA Titanium Disk Insert 5 mm OD x 4 mm THICK cccccccccscscssscscccccccecccececeesseceeeceseeseeeess AFEDOSOPO40TI Tungsten Disk Insert 5 mm OD x 4 MM THICK cscwcasscassdonsdaeveansancadevsdneweansaacadewednereencanceenes AFEDOSOPO40W Fine Disk Ins eh aia FIG aa ne AFEDOSOPO40ZN CAUTION A Maximum Rotation Rate 3000 RPM Do not rotate at rates higher than the maximum rotation rate ATTENTION Vitesse de rotation maximum 3000 TR MIN Ne mettez pas l appareil en rotation des vitesses sup rieures la vitesse de rotation maximum i OPERATING TEMPERATURE RANGE 15 C to 25 C Do not use this electrode outside the operating temperature range 70 E5HT Series HotSpot RDE Tips These RDE tips feature a 15 mm OD PEEK shroud around a 5 mm OD disk electrode The PEEK shroud permits these RDE tips to be used at temperatures up to 80 C The
107. n and G Karlberg Apparatus for Electrochemical Studies of Corrosion Processes in Flowing Systems in Physico Chemical Hydrodynamics edited by B Spalding London Adv Publications 1977 461 RA Holser G Prentice RB Pond and R Guanti Use of Rotating Cylinder Electrodes to Simulate Turbulent Flow Conditions in Corrosion Systems Corrosion 46 1990 764 TY Chen AA Moccari and DD Macdonald Development of Controlled Hydrodynamic Techniques for Corrosion Testing Corrosion 48 1992 239 S Nesic GT Solvi and S Skjerve Comparison of Rotating Cylinder and Loop Methods for Testing CO2 Corrosion Inhibitors British Corrosion Journal 32 1997 269 ASTM G 170 Standard Guide for Evaluating and Qualifying Oilfield and Refinery Corrosion Inhibitors in the Laboratory 2001 ASTM G 185 Standard Practice for Evaluating and Qualifying Oil Field and Refinery Corrosion Inhibitors Using the Rotating Cylinder Electrode 2006 DRU10002 REV 002 APR 20 144 11 Glossary Anodic Current Banana Cable Banana Jack Banana Plug BNC Connector Brush Contacts Cathodic Current Flow of charge at an electrode as a resulf of an oxidation reaction occurring at the electrode surface For a working electrode immersed in a test solution an anodic current corresponds to flow of electrons out of the solution and into the electrode A banana cable is a single wire one conductor signal cable often used to make connections between various ele
108. nt J Appl Electrochem 13 1983 3 24 Y Garsany OA Baturina KE Swider Lyons and SS Kocha Experimental Methods for Quantifying the Activity of Platinum Electrocatalysts for the Oxygen Reduction Reaction Analytical Chemistry 82 2010 6321 6328 25 HA Gasteiger SS Kocha B Sompalli and FT Wagner Activity benchmarks and requirements for Pt Pt alloy and non Pf oxygen reduction catalysts for PEMFCs Applied Catalysis B Environmental 56 2005 9 35 26 UA Paulus A Wokauna GG Scherera TJ Schmidt V Stamenkovic NM Markovic and PN Ross Oxygen reduction on high surface area Pt based alloy catalysts in comparison to well defined smooth bulk alloy electrodes Electrochimica Acta 47 2002 3787 3798 27 UA Paulus TJ Schmidt HA Gasteiger and RJ Behm Oxygen reduction on a high surface area Pt Vulcan carbon catalyst a thin film rotating ring disk electrode study J of Electroanalytical Chem 495 2001 134 145 28 TJ Schmidt UA Paulus HA Gasteiger and RJ Behm The oxygen reduction reaction on a Pt carbon fuel cell catalyst in the presence of chloride anions J of Electroanalytical Chem 508 2001 41 47 29 G Brisard N Bertranda PN Ross and NM Markovic Oxygen reduction and hydrogen evolution oxidation reactions on Cufhkl surfaces J of Electroanalytical Chem 480 2000 219 224 30 L Genies R Faure and R Durand Electrochemical reduction of oxygen on platinum nanoparticles in alkaline media Electrochimica Acta 44 19
109. nt to the limiting current plateau is the mass transport limited current In actual real world experiments the wave may be observed on fop of a background current and furthermore the background current may be slightly sloped see Figure 10 5 This undesired background current may be due to interference from oxidation or reduction of impurities or of the solvent itself The background current may also be due to capacitive charging and discharging of the ionic double layer that forms next to the polarized electrode surface When attempting to measure the desired Faradaic mass transport limited current at a rotating electrode if is offen necessary to account for the undesired possibly sloping background current If the background current has a constant slope across the entire voltammogram then if is fairly easy to extrapolate the sloping baseline to a point underneath the limiting current plateau see Figure 10 5 left The limiting current is measured as the vertical distance between the plateau and the extrapolated baseline In voltammograms where there is more than one wave the plateau for the first wave Is used as the baseline for the second wave see iraz in Figure 10 5 left In some cases the slope of the background current is not constant across the entire voltammogram That is the slope of the baseline leading up to the wave can be different than the slope of the plateau after the wave It can be very difficult to di
110. o smaller boxes in the carton The control unit 10 is packed inside the larger box and the smaller box holds additional components Remove both boxes and set aside Then carefully remove the enclosure window 7 and the enclosure base 4 from the box The center post 1 is pre installed in the enclosure base Open the smaller box It should contain the motor unit 2 the support collar 5 the cell platform 3 the side post 6 a standard three pronged laboratory clamp with right angle mount and a small bag containing two banana cables and some additional assembly hardware Note The outer diameter of the side post 6 shown in these photos is 5 8 15 9 mm but in some alternate rotator configurations this diameter may be 1 2 12 7 mm 27 Locate the small bag of hardware Remove the four pins and four screws Place each screw in one of the pre drilled holes along the side walls of the enclosure two on the left and two on the right Install the pins onto the screws Properly installed pins will point inwards as shown Locate the support collar 5 side post 6 and three pronged laboratory clamp with right angle mount cell platform 3 and the large plastic washer usually shipped in the hardware bag Slide the cell platform 3 onto the center post and position it near the bottom of the center post 1 with the platform facing up Tighten the knob to secure the cell platform to the cente
111. ode and toward the ring electrode The ring electrode is held constant at a positive oxidizing potential throughout the experiment Some but not all of the ferrocyanide generated at the disk travels close enough fo the ring electrode that if is oxidized back to ferricyanide Thus an anodic current is observed at the ring electrode due fo the oxidation of ferrocyanide fo ferricyanide at the ring Fe CN Fe CN e oxidation of ferrocyanide to ferricyanide at ring The measured ratio of the ring anodic limiting current to the disk cathodic limiting current is the empirical collection efficiency As the rotation rate increases both the disk and the ring currents increase see Figure 10 10 Because both the anodic and cathodic limiting currents are proportional to the square root of the rotation rate the empirical collection efficiency is expected to be independent of the rotation rate Once the collection efficiency value has been established empirically for a particular RRDE if can be treated as a property of that particular RRDE even if the RRDE is used to study a different half reaction in a different solution on a different day Although the empirically measured collection efficiency Nempirical is ratio of two currents with opposite mathematical signs anodic and cathodic the collection efficiency is always expressed as a positive number N empirical T VLIMITING RING l LIMITING DISK 10 5 3 Generator Collector Exp
112. of this RMA form in each carton and ship to the Factory Return Service Address below FACTORY RETURN SERVICE ADDRESS Pine Instrument Company ATIN RMA lt RMA number gt 104 Industrial Drive Grove City PA 16127 USA Phone 1 724 458 6391 Return Material Authorization Required Do not ship equipment to the factory without first obtaining a Return Material Authorization RMA form from Pine Research Instrumentation Inc LIMITED WARRANTY The Pine MSR Rotator Pine part number AFMSRCE hereafter referred to as WARRANTED INSTRUMENT offered by Pine Research Instrumentation Inc hereafter referred to as SUPPLIER is warranted to be free from defects in material and workmanship for a one 1 year period from the date of shipment to the original purchaser hereafter referred to as the CUSTOMER if used under normal laboratory conditions SUPPLIER s obligation under this warranty is limited to replacing or repairing parts which shall Upon examination by SUPPLIER personnel disclose to SUPPLIER s satisfaction to have been defective The CUSTOMER may be obligated to assist SUPPLIER personnel in servicing the WARRANTED INSTRUMENT SUPPLIER will provide remote support via telephone or internet to guide the CUSTOMER to diagnose and effect any needed repairs In the event that remote support is unsuccessful in resolving the defect SUPPLIER may recommend that the WARRANTED INSTRUMENT be returned to SUPPLIER for repair This
113. ograms with facile kinetics see Figure 10 7 with a set of voltammograms with sluggish kinetics see Figure 10 9 the mass transport limited current plateau marked by red circles in each figure is shifted further away from the standard electrode potential E when there are slow kinetics Stated another way when a sluggish redox half reaction is studied with a rotating disk electrode a larger overpotential must be applied to the electrode to overcome the sluggish kinetics and reach the mass transport limited current This distortion of the ideal sigmoidal shape of the voltammogram can be exploited as a way to measure the standard rate constant k The general approach is to acquire a set of voltammograms at different rotation rates i e perform a Levich study and then plot the reciprocal current sampled at particular locations along the rising portion of each voltammogram on a Koutecky Levich Plot In the example provided see Figure 10 9 left the Current was sampled at two locations along the rising portion of the voltammograms at 0 and 50 mV vs E marked with blue triangles and purple squares and at one location on the limiting current plateau at 350 mV vs E marked with red circles A linear relationship is evident see Figure 10 9 right when these sampled currents are plotted on a Koutecky Levich Plot For the set of currents sampled on the limiting current plateau red circles an extrapolation back to the vertical a
114. on Further details regarding Koutecky Levich theory including various forms of the Koutecky Levich equation which pertain to different electrochemical processes can be found in the literature 10 5 Rotating Ring Disk Electrode RRDE Theory Soon after the rotating disk electrode was developed the idea of putting a ring electrode around the disk electrode was introduced and the rotating ring disk electrode was born 2 171 In this ring disk geometry the overall axial flow pattern initially brings molecules and ions to the disk electrode Then the subsequent outward radial flow carries a fraction of these molecules or ions away from the disk electrode and past the surface of the ring electrode This flow pattern allows products generated upstream by the half reaction at the disk electrode to be detected as they are swept downstream past the ring electrode Two of the key parameters which characterize a given ring disk geometry are the collection efficiency 4 and the transit time The collection efficiency is the fraction of the material from the disk which subsequently flows past the ring electrode and can be expressed as a fraction between 0 0 and 1 0 or as a percentage Typical ring disk geometries have collection efficiencies between 20 and 30 The transit time is a more general concept indicating the average time required for material at the disk electrode to travel across the gap between the disk and the ring electrode
115. on corresponds fo the ring Figure 4 10 Stackable Banana Connector with Optional Stud Connector The jumper cables used to short the opposing brushes feature stackable banana plugs If the cell cables from the potentiostat also terminate with banana plugs then these plugs can simply be inserted directly into either end of the jumper cable If the cell cables from the potentiostat terminate with alligator clips then the easiest way to connect such alligator clips is to first insert a banana stud connector into the jumper cable see Figure 4 10 The small tab on the banana stud provides a good place to attach the alligator clip Figure 4 11 Routing Cables out of the Enclosure 4 4 3 Routing Cables and Tubing The motor control cable may be routed out of the top of the enclosure to connect the motor unit to the control unit see Figure 4 11 The enclosure has DRU 10002 REV 002 APR 2015 50 slots along the bottom of the window that provide clearance for routing cell cables and any tubing out of the enclosure If required cables and tubing may be routed through the back panel by drilling small holes in the panel Any such drilled holes should have a diameter no greater than 13 0 mm 0 5 in 4 5 Proper Grounding To avoid issues with signal noise when making electrochemical measurements if is important to properly ground all metal objects near an electrochemical cell to the earth ground This generally includes the
116. on efficiency Napparent re RING osx By comparing the apparent collection efficiency Napparent to the previously measured empirical collection efficiency Nempirca for the same RRDE it is possible to deduce the rate at which the competing chemical pathway is converting X to Z That is it is possible fo use an RRDE generator collector experiment fo measure the kinetic behavior of unstable electrochemical intermediates Whenever Napparent Nempirical it IS an indication that the decay rate of the intermediate via the X 7 pathway is small with respect to the transit time required for X to travel from the disk to the ring One way to shorten the transit time is to spin the RRDE at a faster rate At high rotation rates the apparent collection efficiency should approach the empirical collection efficiency Conversely at slower rotation rates the apparent collection efficiency may be smaller Napparent lt Nempirical D CaUsSe some of the intermediate is consumed by the competing chemical pathway before X can travel to the ring By recording a series of rotating ring disk voltammograms at different rotation rates and analyzing the results if is possible to estimate the rate constant k associated with the intermediate chemical decay pathway Various relationships have been proposed for this kind of analysis ll and one of the simplest is shown below FINE RESEARCH INSTRUMENTATION 5 139 N 1 3 El 24 5 4 98 z Z
117. oring the Rotation Rate 4 7 3 External Control of the Rotation Rate 4 7 4 External Motor Stop Control O O1 R ND O0 NO NO DID ND ON ND oO AO O O KR ND O DRU10002 REV 002 APR 20 4 8 Circuit Protection 58 5 Electrodes 59 5 1 Electrode Handling Precautions 97 Oe Shafts 63 5 3 RDE Tips 66 5 4 Single Piece RDE Designs 7 5 5 RRDE Tips 72 5 6 15 mm OD RCE Tips 75 org 12mm OD RCE Tips 76 6 Maintenance 77 6 1 Routine Cleaning 77 6 2 Brush Replacement 77 6 2 1 Internal Brush Replacement 77 6 2 2 Complete Brush Assembly Replacement 80 6 3 Lower Bearing Replacement 8 6 4 Removing the Motor Coupling Assembly 83 6 5 Installing a New Motor Coupling Assembly 87 6 5 1 Motor Control Cable Wiring 89 6 6 Rotation Rate Calibration 9 6 Changing the Input Rotation Rate Ratio 101 6 8 Changing the Motor Stop Signal Logic 103 7 Parts and Accessories 107 7 1 Mechanical Parts and Hardware 107 7 2 Power Cords 110 To Power Supplies 113 8 Troubleshooting 116 Storage and Shipment 120 10 Theory 121 10 1 Forced Convection 121 10 2 Half Reactions 122 10 3 Volfammetry 123 10 3 1 Voltammogram Plotting Conventions 126 10 3 2 Measuring Limiting Currents 128 10 4 Rotating Disk Electrode RDE Theory 130 10 4 1 Levich Study 131 10 4 2 Koutecky Levich Analysis 133 10 5 Rotating Ring Disk Electrode RRDE Theory 135 10 5 1 Theoretical Computation of the Collection Efficien
118. ot negative cathodic reducing potential toward the right as per classical polarography tradition Furthermore some researchers plot anodic oxidizing current upward along the vertical axis while others plot cathodic reducing current in the upward direction This means there are four possible conventions for plotting a voltammogram and one should always take a moment to ascertain the orientation of the axes before interpreting a voltammogram Fortunately of the four possible ways to plot a voltammogram only two are commonly used The older tradition based on classical polarography plots cathodic current upwards along the vertical axis and negative cathodic reducing potentials toward the right along the horizontal axis A complex voltammogram involving four different limiting currents see Figure 10 4 left illustrates this convention which is sometimes called the North American convention JINE RESEARCH INSTRUMENTATION Potential mV vs E 0 10 Time sec anodic current cathodic current t anodic mass transport limited current ita 0 10 Time sec Current HA 100 90 300 200 Potential mV vs E 127 100 200 300 Figure 10 3 A Voltammogram is a Plot of Current versus Potential The North American Convention 120 cathodic current anodic current 120 1000 0 1000 cathodic sweep anodic
119. otation rate see Figure 10 7 left The currents measured during a Levich study are usually plotted against the square root of the rotation rate on a graph called a Levich plot As predicted by the Levich equation the limiting current see red circles on Figure 10 7 right increases linearly with the square root of the rotation rate with a slope of 0 620 n F A D v C and the line intercepts the vertical axis at zero It is common to FINE RESEARCH INSTRUMENTATION DRU10002 REV 002 APR 2015 132 choose a set of rotation rates that are multiples of perfect squares such as 100 400 900 1600 RPM etc to facilitate construction of this plot 200 200 180 3600 RPM 180 160 160 140 140 120 120 100 100 900 RPM 80 80 400 RPM Current uA Current pA 60 60 40 eu 40 20 150 100 50 0 50 100 150 200 0 5 10 15 20 Potential V vs E Rotation Rate rad s Figure 10 7 Levich Study Voltammograms at Various Rotation Rates If the electrochemical half reaction observed during a Levich study is a simple and reversible half reaction with no complications due to sluggish kinetics or coupled chemical reactions then the shapes of the mass fransport controlled voltammograms will be sigmoidal regardless of the rotation rate This means that the current observed at any given potential along the voltammogram will vary linearly with the square root of the rotation rate see Figure 10 7 right
120. ounted In a sturdy and chemically resistant enclosure base A flat cell platform can also be positioned along the center post making if easy to raise and lower the cell with respect fo the motor unit The electrochemical cell can be further secured by clamping if fo a side post located adjacent to the center post WARNING Rotating shaft Do not turn on the rotator or rotate the electrode shaft unless the enclosure window is secured to all four pins as shown below Use extreme caution when operating the rotator at rotation rates above 2000 RPM AVERTISSEMENT Arbre en rotation Ne mettez pas le rotateur en marche et ne marche ni l arbre de l lectrode en rotation si la fen tre du bo tier n est pas ferm e l aide des quatre broches tel qu indiqu ci dessous Soyez extr mement prudent lorsque vous utilisez le rotateur des vitesses de rotation sup rieures 2000 tr min The motor unit and electrochemical cell are enclosed on the back side by a rear wall permanently attached to the enclosure base The cell and motor are further enclosed on the front side by a transparent enclosure window The PAINE DRU10002 REV 002 APR 2015 16 enclosure window can be removed fo set up the cell but the enclosure window must be securely mounted to the enclosure base before rotating the electrode The rotator may be used with rotating disk electrodes RDEs rotating ring disk electrodes RRDEs and rotating cylinder electrode
121. ower cord disconnected remove the cover from the control unit Loosen the screw that secures the main analog board to the front panel and then carefully remove the analog board L aN Se On the board locate the configuration pins with the designation JP1 There is a small jumper that can be placed in one of two positions at this location DRU10002 REV 002 APR 2015 106 Place the jumper across one of the two positions shown below Choose the position required for the particular potentiostat being used with the rotator Active LOW Position Active HIGH Position Reinstall the board in the control unit and secure the board to the front panel At this point the motor stop signal logic has been changed Make a note in a log book or place a sticker on the control unit to indicate the new logic ine RESEARCH INSTRUMENTATION N 107 7 Parts and Accessories 7 1 Mechanical Parts and Hardware There are several moving parts on the rotator which are subject to normal wear during routine use This section describes these parts in more detail Brush Replacement Kit Order this kit to replace a worn brush contact This kit includes a spring loaded brush and a required hex key tool The replacement brush may be mounted in any of the four brush holders on the rotator Special low humidity brushes are available for Use in dry environments such as inside a glove box Description Part Number Standard Br
122. oxide formation is called the two electron pathway and if is undesirable for a number of reasons including the fact that peroxide can damage various polymer membrane materials found in a fuel cell Further details on how to use an RRDE generator collector experiment to distinguish between the two electron and four electron ORR pathways can be found in the electrochemical literature 24 27 10 6 Rotating Cylinder Electrode RCE Theory The rotating disk and ring disk electrodes were developed primarily as a result of academic electroanalytical chemistry research In contrast the theory for the rotating cylinder electrode RCE was developed by industrial researchersi S71 in the corrosion and electroplating communities While the flow of solution at a rotating disk or ring disk is laminar over a wide range of rotation rates the flow at the surface of a rotating cylinder is turoulentl22 at all but the slowest rotation rates Thus the RCE is an excellent tool for creating and controlling turbulent flow conditions in the laboratory and it is most commonly used to mimic turbulent corrosion conditions found in large scale industrial settings such as oilfield pipeline corrosion 47 6 The turbulent flow at a rotating cylinder electrode conveys material from the bulk solution towards the electrode surface While the bulk solution remains well stirred by the main vortex induced by the rotating electrode the layer of solution adjacent to the cy
123. r des vitesses de rotation sup rieures 2000 tr min PAINE DRU10002 REV 002 APR 2015 CAUTION Do not exceed the maximum rotation rate for an electrode Each type of rotating electrode has a specific maximum rotation rate limitation Consult the documentation for the specific electrode being used in order to learn the maximum rotation rate for that electrode ATTENTION Ne d passez pas la vitesse de rotation maximum pour une lectrode Chaque type d lectrode rotative poss de une vitesse de rotation maximum sp cifique Consultez la documentation pour l lectrode sp cifique utiliser pour conna tre la vitesse de rotation maximum de l lectrode CAUTION Always turn the rotation rate control knob completely counterclockwise towards the zero rotation rate position before turning on the rotator ATTENTION Tournez toujours le bouton de commande de la vitesse de rotation compl tement dans le sens inverse des aiguilles d une montre vers la position vitesse de rotation gale z ro avant de mettre le rotateur en marche WARNING Rotating shaft Entanglement hazard Turn off the power to the rotator and disconnect the power cord from the power source before installing or removing the electrode shaft or before installing or removing an electrode tip on the end of the shaft AVERTISSEMENT Arbre en rotation Danger d encheve trement Eteignez le rotateur et d branchez le cordon d
124. r and the serial number A matching serial number is also found on a similar label located on the motor unit In laboratories with multiple MSR rotators if is important to keep the control unit together with the matching motor unit because the two components are calibrated together as a system see Section 6 6 1 6 3 Model Numbers Pine MSR rotator model numbers have the format AFMSRWXYZ where W X Y and Z are each single characters used to indicate the particular configuration of the rotator see Table 1 1 The final characters X Y and Z may be blank Part numbers for electrodes and other accessories compatible with the MSR rotator are described in more detail later see Section 5 and Section 7 Model Sumber Model Name AJF Eu Pine MSR Rotator alriulsletels aial Model 636A Rotator ALF iM S R 7 1 0 A Model 710A Rotator Table 1 1 Pine Rotator Part Numbering DRU10002 REV 002 APR 2015 1 7 Specifications All soecifications are subject fo change without notice Power Shipping Information Dimensions LxWxH Operating Temperature Motor Motor Protection Maximum Continuous Torque Rate Control Rate Display Rate Accuracy Controls Rotation Rate Input Rotation Rate Output Rotator Motor Stop Earth Ground Common Jacks Slew Rate of Motor Bandwidth 100 240 VAC 10 50 60 Hz 2A 60 pounds 27 kg 24 0 x 24 0 x 24 0 in 61 x 61 x 61 cm 11 4x 10 1 x 5 7
125. r coupling unit There should be one cable fie securing the cables to the motor black as shown below Do not remove this cable fie Remove any extra cable ties i e around the green part of the motor so that the cable can move freely Align the threaded holes in the new motor with those in the brush chamber and push the motor up into the support Carefully feed the cables through the hole as shown in the figure below Secure the motor and chamber to the support using four screws Connect the internal cable within the cowling to the motor by joining the two white connectors together Replace the cowling on top of the motor and secure if with two screws 89 6 5 1 Motor Control Cable Wiring The motor control cable is a 15 conductor cable that is wired straight thru from a male HD 15 connector on one end to a female HD 15 connector on the other end Although there are 15 conductors only four signals actually travel through the cable and several conductors are grouped together see Table 6 1 The HD 15 connector on top of the motor unit connects internally with the motor wiring harness which has four colored signal wires see Table 6 2 Motor Supply Tachometer Tachometer e red Tachometer Tachometer Table 6 2 Internal Motor Cable Wiring DRU10002 REV 002 APR 20 90 O 71 N N Co a 0 isai Figure 6 1 Rotator Calibration Toolkit including simple hand
126. r post Next slide the support collar 5 on fo the center post and position if slightly above the midpoint of the center post with the knob on the left side Tighten the knob fo secure the support collar to the center post Slide the plastic washer on the center post and allow if fo rest on top of the support collar Carefully slide the motor unit 2 on to the center post 1 until if rests on the support collar 5 Tighten the knob fo secure the motor unit to the center post DRU10002 REV 002 APR 2015 28 Note The relative vertical positions of the cell platform support collar and motor unit may be adjusted as needed to fit the specific size and shape of a particular electrochemical cell There are several holes in the floor of the enclosure base 4 which are threaded to accept the side post 6 Choose one of these holes and install the side post in if Then mount the laboratory clamp on to the side post There are two short banana cables red and blue which serve as jumpers between the left and right brush connections Use the red cable to connect the upper red pair of brush connections and use the blue cable to connect the lower blue pair of brush connections running the wires behind the assembly as shown Insert One banana plug stud into the red banana cable and insert the other banana plug stud into the blue banana cable These flat studs are an ideal place to make connections using allig
127. r this reason it is common practice to empirically measure the collection efficiency using a well behaved redox system rather than fo rely upon a computed value 150 100 20 ring current anodic 90 100 116 1 uA disk current icathodic 150 174 2 uA 200 290 200 150 100 50 0 50 100 150 200 Disk Potential V vs E Figure 10 10 Rotating Ring Disk Voltammograms at Various Rotation Rates The ferrocyanide ferricyanide half reaction is a simple single electron reversible half reaction that is offen used as the basis for measuring collection efficiency FINE RESEARCH INSTRUMENTATION 5 The RRDE is placed in a solution containing a small concentration 10 mM of potassium ferricyanide K3Fe CN 4 in a suitable aqueous electrolyte solution such as 1 0 M potassium nitrate KNO3 and is operated af rotation rates between 500 and 2000 RPM Initially both the ring and the disk electrodes are held at a sufficiently positive potential that no reaction occurs Then the potential of the disk electrode is slowly swept 50 mV sec towards more negative potentials and a cathodic current is observed which corresponds to the reduction of ferricyanide to ferrocyanide at the disk Fe CN e gt Fe CN lt reduction of ferricyanide to ferrocyanide at disk As ferricyanide is reduced at the disk electrode the ferrocyanide generated by this process is swept outward radially away from the disk electr
128. right side as shown above but if is understood that the reaction may occur in either direction depending upon the potential applied to the electrode FINE RESEARCH INSTRUMENTATION 5 123 Each half reaction has an associated standard electrode potential E which is a thermodynamic quantity related to the free energy associated with the equilibrium Like many other standard thermodynamic quantities the standard electrode potential corresponds to a given standard state The standard state corresponds to a thermodynamic system where the activities of O and R are Unity Le when all solution concentrations are 1 0 mol L all gases are present at 1 0 atm partial pressure and other materials are present as pure phases with unity activity To account for the likely possibility of non unity activities the Nernst equation see below can be used to express the equilibrium electrode potential ENeERNSTIAN in terms of the actual activities ENerNsTIAN E RT nF In do ar where F is the Faraday constant F 96485 C mol R is the ideal gas constant R 8 3145 J mol K and T is the temperature K Usually the activities of molecules or ions dissolved in solution are assumed to be the same as their molar concentrations so the Nernst Equation ts offen written as follows ENernstTAN E RT nF In Co Cr where Co and CR are the concentrations of the dissolved molecules or ions in the oxidized and reduced form
129. rm O with no Reduced Form R 125 Response to a Potential Sweep Anodic from a Solution Initially Containing only the Reduced Form R with no Oxidized Form O 126 A Voltammogram is a Plot of Current versus Potential esseeeeessserersess 127 Two Popular Volfammogram Plotting Conventions 127 Sloping Backgrounds in Volfammograms ss 129 Volfammogram for a Solution Containing Both O and R eeeeeeeeeees 129 Levich Study Volfammograms at Various ROTATION RATES cceeeece eens 132 Levich Study Limiting Current versus ROTATION ROTC 2 ceccceeeeeeccceeeeeeeeeeees 132 Koutecky Levich Study Volfammograms with Sluggish Kinetics 133 Rotating Ring Disk Voltammograms at Various Rotation Rates 136 DRU 10002 REV 002 APR 2015 1 1 Scope The MSR rotator is a solid state controlled servo system designed to rotate an electrode in an electrochemical cell This manual describes the proper use of the MSR rotator and covers routine operating procedures periodic maintenance and calibration and safety Issues The reader of this manual is assumed fo have some basic knowledge of electronics electrochemistry and the modern practice of voltammetry While some background information is presented in this manual the reader is referred to the appropriate scientific literature for more detail regarding the theory and practice of hydrodynamic voltammetry Pine Research Instrumenta
130. ront Panel Circuit This breaker only trips if the Current passing through the Breaker Trips motor windings is high enough to potentially damage the motor This could occur if the electrode is spinning in a particularly viscous liquid if the shaft is rubbing against something or if an applied periodic waveform controlling the rotation rate has too great an amplitude or frequency This breaker thermal type is sized fo limit the average motor current to within the motor specification Running the motor at a high modulation frequency or with large amplitude changes or a combination of the two may cause tripping If may be necessary to reduce the modulation frequency and or amplitude to prevent tripping of the breaker Excessive If the rotator has a standard lower bearing assembly with Audible a stainless steel bearing then this bearing may be Noise corroded If corroded replace the entire lower bearing assembly lf the rotator has a special lower bearing assembly with a ceramic bearing then some audible noise is to be expected from the ceramic bearing This special bearing assembly should be replaced if there is other evidence that it is damaged DRU10002 REV 002 APR 2015 118 Suggested Cause or Action Internal spindle bearings are worn contact the factory Rotator When the rotation rate knob is in the full Spins counterclockwise position if is natural to expect that the Backwards rotation rate should be ex
131. rotator power cable or the motor control cable to the control unit be sure the control unit power switch is off and the rotation rate knob is turned to the fully counterclockwise position ATTENTION Avant de reconnecter le c ble d alimentation du rotateur ou le cable de commande du moteur l unit de commande assurez vous que l interrupteur de l unit de commande est en position teinte et que le bouton de commande de la vitesse de rotation est compl tement tourn dans la position inverse des aiguilles d une montre Reconnect the motor control cable from the control unit to the motor unit Reconnect the power cable from the power source to the control unit WARNING AN Do not turn on the rotator or rotate the electrode shaft if the shaft is not securely mounted in the motor coupling Inspect the shaft to be certain that it is securely mounted AVERTISSEMENT Ne mettez pas le rotateur en marche ni l arbre de l lectrode en rotation si l arbre n est pas correctement raccord au moteur Inspectez l arbre pour vous assurer qu il est bien fix With the rotation rate knob in the fully counterclockwise position turn on the control unit Slowly turn the rotation rate knob clockwise until the shaft is rotating between 100 and 200 RPM While the shaft is slowly rotating 100 fo 200 RPM inspect the rotating shaft and tip to assure that both are rotating properly about the axis of rotation If the shaft or tip is wobbling
132. round connection for the third prong on the power cord WARNING Failure to connect the third prong of the power cord to a proper earth ground may impair the protection provided by the system AVERTISSEMENT L absence de connexion de la troisi me broche du cordon d alimentation une prise de terre appropri e peut alt rer la protection fournie par le syst me CAUTION A detachable main power cord is provided with the rotator Do not replace this cord with an inadequately rated cord ATTENTION Un cordon d alimentation amovible est fourni avec le rotateur Ne remplace pas ce cordon par un cordon de calibre inad quat 31 4 Operation This section of the manual discusses information pertaining to routine operation of the rotator Users of the rotator should be familiar with all of the information in this section prior to operating the rotator 4 1 The Rotating Shaft The electrode shaft normally rotates in a clockwise direction as viewed from the top of the rotator The upper end of a standard shaft has a 1 4 6 85 mm outer diameter When properly mounted in the rotator the upper 2 7 68 mm of the shaft is inside the motor unit while the remaining length of the shaft extends down below the motor unit The rotator accepts shafts for use with Rotating Disk Electrodes RDE Rotating Cylinder Electrodes RCE or Rotating Ring Disk Electrodes RRDE Electrical connection is accomplished using one or more sil
133. route this cable well away from noise sources such as power cords networking cables or video monitors Note Cell cables on newer model Pine potentiostats use GREEN to mark 1 the counter electrode connection and WHITE to mark the reference electrode connection see Figure 4 7 u 7 Older Pine bipotentiostats use RED to mark the counter electrode and use a BNC connector for the reference electrode PAINE DRU10002 REV 002 APR 2015 46 Tip There is no universally accepted color coding scheme for marking potentiostat cell cable connections If you are using the rotator wilh a third party potentiostat consult the potentiostat documentation for information about the cell cable markings 4 4 1 RDE and RCE Wiring There are two pairs of brushes which provide electrical contact with the rotating shatt see Figure 4 8 The Upper pair of brush contacts red is used to make electrical contact with a rotating disk electrode RDE or a rotating cylinder electrode RCE To make good contact on opposite sides of the rotating shaft both of the red brushes left and right sides should be used Use a short banana jumper cable to connect the opposing brushes together see Figure 4 8 and then connect the working electrode cable s from the potentiostat to the jumper cable Figure 4 8 Brush Connections for a Rotating Disk Electrode RDE or a Rotating Cylinder Electrode RCE 47 Tip Most modern potentiosta
134. rtain fo general use of the rotator More specific safety warnings are found in later sections of this document which pertain fo particular operations and procedures involving the rotator Des avertissements de s curit plus sp cifiques se trouvent dans les sections suivantes de ce document concernant les operations ef proc dures particuli res relatives le rotateur WARNING Failure to connect the third prong of the power cord to a proper earth ground may impair the protection provided by the system AVERTISSEMENT L absence de connexion de la troisi me broche du cordon d alimentation une prise de terre appropri e peut alt rer la protection fournie par le syst me WARNING Risk of electric shock Disconnect all power before servicing the rotator AVERTISSEMENT Risque de d charge lectrique D connectez toutes les sources d alimentation avant de proc der l entretien du rotateur WARNING Rotating shaft Do not turn on the rotator or rotate the electrode shaft unless the enclosure window is secured fo all four pins as shown below Use extreme caution when operating the rotator at rotation rates above 2000 RPM AVERTISSEMENT Arbre en rotation Ne mettez pas le rotateur en marche et ne marche ni l arbre de l lectrode en rotation si la fen tre du bo tier n est pas ferm e l aide des quatre broches tel qu indiqu ci dessous Soyez extr mement prudent lorsque vous utilisez le rotateu
135. s RCEs Connections to the rotating electrode shaft are made by two pairs of silver carbon brushes For RDEs and RCEs all four brushes make contact with the rotating shaft and may be shorted together to obtain four points of contact For RRDEs the Upper brush pair contacts the disk electrode and the lower pair contacts the ring electrode 17 2 1 Major System Components The table and photo below see Figure 2 1 show the major system Components Figure 2 1 Major Components of the MSR Rotator System J DRU 10002 REV 002 APR 2015 8 The cell platform support collar and motor Center Post Unit are supported by the center post The motor unit is mounted on the center Motor Unit post and holds the motor and brushes The cell platform supports cells with flat 3 Cell Platform bottom surfaces The support frame is fabricated from a Enclosure Base chemically resistant polymer The support collar helos prevent motor from sUppen ONE unexpectedly sliding down center post The side post is a support for cell clamps and Side Post can be installed in one of two positions This is transparent window covering the 7 Enclosure Window front of the overall enclosure This cable connects the control unit to the motor unit Motor Control Cable The upper pair of brush contacts red is used with rotating disk electrodes RDE and rotating cylinder electrodes RCE The Brush Contacts lower pair of
136. s respectively at the surface of the electrode Note that any liquid or solid phase materials at the electrode surface such as the solvent or the electrode itself have unity activity and thus do not appear in the Nernst equation This half reaction at an electrode can be driven in the cathodic reducing direction by applying a potential to the electrode Eyppriep which is more negative than the equilibrium electrode potential Eappuien lt ENERNSTIAN Conversely the half reaction can be driven in the oxidizing anodic direction by applying a potential more positive than the equilibrium electrode potential Eappuien gt ENERNSTIAN 10 3 Voltammeiry The term voltammetry refers broadly to any method where the electrode potential is varied while the current is measured 2 The terminology associated with voltammetry varies across different industries and academic disciplines but the underlying principles of all voltammetric techniques are very similar The most common form of voltammetry involves sweeping the electrode potential from an initial value to a final value at a constant rate When working in the context of electroanalytical chemistry with a non rotating electrode this technique is called linear sweep voltammetry LSV In the context of corrosion FINE RESEARCH INSTRUMENTATION 5 DRU 10002 REV 002 APR 2015 124 science this kind of technique is usually called linear polarization resistance LPR or a Ta
137. scern exactly where to measure the limiting current along such a FINE RESEARCH INSTRUMENTATION 5 129 voltammogram One approach is fo extrapolate the baseline forward through the wave and also extrapolate the plateau backward through the wave Then the limiting current is measured as the vertical distance between the baseline and plateau at a point corresponding to the center of the voltammogram see ita in Figure 10 5 right 120 60 100 T 80 T 40 _ _ C 60 C 30 9 2 ILA i O O 2 20 10 0 0 200 0 200 400 600 800 1000 1200 200 0 200 400 600 800 1000 1200 Potential mV Potential mV Figure 10 5 Sloping Backgrounds in Voltammograms anodic limiting current ia cathodic limiting current itc Current pA 240 0 240 Potential mV vs E Figure 10 6 Voltammogram for a Solution Containing Both O and R Finally it should be noted that when the oxidized form O and the reduced form R of a molecule or ion are both present in a solution at the same time the voltammogram is likely to exhibit both a cathodic and an anodic limiting current RESEARCH INSTRUMENTATION zi DRU 10002 REV 002 APR 20 130 see Figure 10 6 It can be very difficult fo measure the limiting current properly in this case especially if there is also a sloping background current For this reason most experiments with rotating electrodes are conducted in solutions where only one form o
138. screwing if as shown below It should be possible fo remove the brush assembly by hand Use the small hex key to remove the set screw Note that the required hex key 0 035 is included with the brush replacement kif Note The brush is spring loaded When you remove the set screw the brush will tend to fly out of the brush holder Use a finger to hold it in place as you are removing the set screw After removing the set screw remove and discard the old brush but do not discard the empty brush holder 79 The new replacement brush includes a set screw which is already installed Temporarily remove this set screw Be careful not fo misplace the set screw Carefully slide the new spring loaded brush into the brush holder Be careful to properly align the set screw hole with the slot on the side of the brush holder While squeezing the new brush into the brush holder use the hex key to reinstall the set screw Tighten the set screw until it stops turning Note The set screw should protrude slightly into the slot and the brush should be free to travel to the extent permitted by the width of the slot DRU10002 REV 002 APR 2015 80 Reinstall the brush assembly by threading it back into the side of the rotator Hana tighten the brush assembly Do not use tools to tighten the assembly INTENTIONAL WEAR PERIOD After installing a new brush install a shaft and allow the rotator x
139. se tips fit the standard RRDE shaft and may be used at rotation rates up to 3000 RPM Standard disk materials include gold platinum and glassy carbon Other materials are available upon request Description Part Number Precision RDE amp RRDE Shaft tor TOA O DOS hisser cs AFE6MB Glassy Carbon RDE tip 5 mm OD disk 15 mm OD shroud 80 C limit AFESTOSOGCHT Aluminum RDE tip 5 mm OD disk 15 mm OD shroud 80 C limit oo ee eeeeeeeeeeeeeeees AFESTOSOALHT Copper RDE tip 5 mm OD disk 15 mm OD shroud 80 C limit aeesssesssssecrrrrrrreressess AFESTOSOCUHT Gold RDE tip 5 mm OD disk 15 mm OD shroud 80 C limit oo ccc cece eee eeeeeeeeees AFESTOSOAUHT Nickel RDE tip 5 mm OD disk 15 mm OD shroud 80 C IIMIT oo eee eeeeeeeeeceeeeeeeeeees AFESTOSONIHT Palladium RDE tip 5 mm OD disk 15 mm OD shroud 80 C limit oo cece cece eee AFESTOSOPDHT Platinum RDE tip 5 mm OD disk 15 mm OD shroud 80 C liMit UN AFESTOSOPTHT Silver RDE tip 5 mm OD disk 15 mm OD shroud 80 C limit oo eeeeeseeeeeeeeeeeees AFESTOSOAGHT Tantalum RDE tip 5 mm OD disk 15 mm OD shroud 80 C liIMit eee cee ececeeeeeeees AFESTOSOTAHT Titanium RDE tip 5 mm OD disk 15 mm OD shroud 80 C iImMIT AFESTOSOTIHT Tungsten RDE tip 5 mm OD disk 15 mm OD shroud 80 C limit 0 eeeeeeeeeeeeeeeeeeeees AFESTOSOWHT Zinc RDE tip 5 mm OD disk 15 mm OD shroud 80 C IIMIT wo eeeeeeeeeeeeeeeeeeeees AFESTOSOZNHT CAUTION A Maximum Rotation Rate 3000 RPM
140. solation between the DC Common the earth ground and the instrument Chassis as possible Such isolation increases flexibility when working with electrochemical cells that may contain earth grounded components But in almost all cases a cell containing a rotating electrode does not have any earth grounded electrodes allowing some trade off between flexibility and the use of earth grounding to reduce signal noise DRU10002 REV 002 APR 2015 54 4 6 Using the Rotator in a Glove Box The rotator may be placed in a glove box when working with air or moisture sensitive Compounds A smaller base sold separately is available for use in a glove box see Figure 4 14 It is important to Understand that the low humidity environment found in most glove boxes increases the rate of wear on both the brush contacts and the internal brushes within the motor itself Figure 4 14 Glove Box Configuration To mitigate the wear rate of the brush contacts if is recommended that four special low humidity brushes sold separately be installed prior to placing the rotator in the glove box Contact Pine for more details CAUTION A Using the rotator in a dry environment such as a low humidity y glove box will increase the wear rate of the internal motor brushes See Section 6 5 for more information about how to replace a worn motor ATTENTION L utilisation du rotateur dans un environnement sec tel qu une bo te gants a faible t
141. srieataacceetta 32 Proper left and Improper right Shaft Insertion POSITIONS eeeeccceseccens 36 IMstaling a Tip onto de PIECE LEE I ine ESE EN 37 Properly Supported and Clamped Electrochemical Cells eee 4 Enclosure Properly Mounted on All Four PINS ccc cece eeeeccceeeccceeessseeeesseeeeess 44 Connection of Counter and Reference Electrodes cc eecccceesessceeeneseeees 45 Brush Connections for a Rotating Disk Electrode RDE or a Rotating CNN SF ESC OC RCE neennerenn o a 46 Brush Connections for a Rotating Ring Disk Electrode RRDE 48 Stackable Banana Connector with Optional Stud Connector 49 Routing Cables out of the ECO Oi Sacre eds escrocs 49 Connect Metal Objects to Earth Ground on Control Box Front Panel 52 Connect Potentiostat to Earth Ground on Control Box Front Panel 53 COVE BOX C ONNGUGT OR a aa ae E E ENAR 54 Connecting the Rotation Rate Control Cable 56 Rotator Calibration Toolkit including simple handheld tachometer 90 Professional Optical Tachometer with Traceable Calibration eee 90 Use of Optical Tachometer with Reflective Target 90 Standard C18 Connection on Power Entry Module ceeeccceeeeseeeeeeeees 110 Location of High Voltage Power Entry and Internal Power Supplies 113 Replacement Internal Power Supplies 0 0 ecescsssesceeeesseeesescuensseneeesseeens 114 Response to a Potential Sweep Cathodic from a Solution Initially Containing only the Oxidized Fo
142. sup rieures la vitesse de rotation maximum re OPERATING TEMPERATURE RANGE 10 C to 80 C Do not use this electrode outside the operating temperature range CHEMICAL INCOMPATIBILTY The shroud material PEEK may be discolored by prolonged exposure to concentrated acids Note RRDE tips with PEEK shrouds are considerably more difficult to polish by hand than those with Teflon shrouds Mechanical polishing is recommended if the appropriate equipment is available DRU10002 REV 002 APR 20 74 E7 Series ThinGap RRDE Tips These ring disk electrode tips feature a Teflon shroud and a thin gap 180 or 320 um between the permanently mounted disk and ring electrodes These Tips fit the standard RRDE shaft and may be used at rotation rates Up fo 3000 RPM Standard disk and ring materials include gold platinum and glassy carbon Other materials are available upon request Description Part Number Precision RDE amp RRDE Shaft for 15 mm OD tips seecscccsuswssdstascantosnsasadsteomasocsosussdutarnencmracetedobewedes AFE6MB ThinGap RRDE Tip glassy carbon disk gold ring 320 um gap AFEZR9GCAU ThinGap RRDE Tip glassy carbon disk platinum ring 320 um gap AFEZR9GCPT ThinGap RRDE Tip glassy carbon disk and ring 320 um gap AFE7RIGCGC ThinGap RRDE Tip Gold disk and ring 180 um gap AFE7R8AUAU ThinGap RRDE Tip platinum disk and ring 180 um gap AFE7R8PIPT ThinGap RRDE Tip gold disk platinum ring 180 um A
143. t in the negative cathodic direction see Figure 10 1 left As the applied potential approaches the standard electrode potential a cathodic current is observed see Figure 10 1 right The cathodic current continues to increase as the potential moves past the standard electrode potential towards more negative potentials The current eventually reaches a maximum value limiting current once the applied potential is sufficiently negative relative to the standard electrode potential At such a negative potential any oxidized form of the molecule or ion O that reaches the surface of the electrode is immediately converted to the reduced form R as shown below O ne R The observed cathodic current is the result of electrons flowing out of the electrode and into the solution The rate of electron flow is limited only by how fast the oxidized form O can arrive at the electrode surface The maximum current observed in this circumstance is called the cathodic limiting current itc Whenever an observed current is limited only by the rate at which material arrives at the electrode surface the current is said to be mass transport limited When working with a rotating electrode the rate of mass transport is related to FINE RESEARCH INSTRUMENTATION 5 125 the rotation rate of the electrode Rotating the electrode at a faster rate increases the rate at which material arrives at the electrode surface Thus the limiting Current
144. t the ring electrode This disk core Is in electrical contact with the 46 Disk Core on Tip surface of the disk electrode This insulating shroud material is typically 47 Insulating Shroud on Shaft Teflon PEEK or KEL F This metal area on the shaft is normally in 48 Ring Contact Area electrical contact with the ring electrode This metal area on the shaft is normally in electrical contact with the disk electrode 49 Disk Contact Area This electrically isolated portion of the shaft 50 Shaft Mounting Area is used to physically mount the shaft in the motor coupling DRU10002 REV 002 APR 20 26 3 Installation 3 1 Site Preparation The rotator system should be located on a sturdy table or laboratory bench with ample clearance around the perimeter of the rotator enclosure The front of the rotator should be unobstructed and there should be at least 20 centimeters clearance on each side and behind the rotator for a total table space of 40 cm x 60 cm The location should also include enough space for the control unit 30 cm x 30 cm and vertical clearance to easily raise and lower the motor unit 3 2 Unpacking and Setting Up the Rotator Note The numbers in parentheses in the installation instructions below correspond to the numbering used in the tables and figures found in Section 2 of this manual Insoect the contents of the shipping carton Remove the top piece of cardboard to reveal the tw
145. tercepts the vertical axis above zero however this is a strong indication that the half reaction is limited by sluggish kinetics rather than by mass transport 450 2500 400 350 3600 RPM L 2000 q 3 2500 RPM T 2 1500 aa 1600 RPM Q O 200 900 RPM x 1000 150 f a RPM 100 O a e 50 yy 100 RPM Oo 0 200 100 0 100 200 300 400 500 0 0 04 02 03 i Potential V vs E Rotation Rate rad s 12 Figure 10 9 Koutecky Levich Study Voltammograms with Sluggish Kinetics 10 4 2 Koutecky Levich Analysis When the rate of a half reaction occurring at an electrode surface is limited by a combination of mass transport and sluggish kinetics if is often possible to use a rotating disk electrode to elucidate both the mass transport parameters such as the diffusion coefficient and the kinetic parameters such as the standard rate constant k from a properly designed Levich study A full treatment of this kind of analysis is beyond the scope of this document but the following is a general description of how to extract kinetic information trom a set of rotating disk voltammograms When the electron transfer process at an electrode surface exhibits sluggish kinetics the voltammogram appears stretched out along the potential axis and the shape of the sigmoidal wave is slightly distorted Comparing a set of PINE RESEARCH INSTRUMENTATION 2 DRU10002 REV 002 APR 2015 134 voltamm
146. teur en fonction de la position de la cellule de verre de telle sorte que l embout d lectrode soit immerg e sur environ 1 cm dans la solution d essai Une immersion excessive peut entrainer la corrosion de l arbre ou d embout d lectrode en provoquant l infiltration de liquides dans le joint situ entre l arbre et l embout d lectrode 43 CAUTION Center the rotating electrode within the opening on the cell so that it does not rub against the walls of the opening Damage will occur if the rotating shaft or tip abrades against these walls ATTENTION Centrez l lectrode rotative dans l ouverture de la cellule pour qu elle ne frotte pas les bords de l ouverture Le frottement des bords de la cellule par l arbre ou par l embout d lectrode entrainera des dommages DRU10002 REV 002 APR 20 44 4 3 The Enclosure WARNING A Rotating shaft Do not turn on the rotator or rotate the electrode shaft unless the enclosure window is secured fo all four pins as shown below Use extreme caution when operating the rotator at rotation rates above 2000 RPM AVERTISSEMENT Arbre en rotation Ne mettez pas le rotateur en marche et ne marche ni l arbre de I lectrode en rotation si la fen tre du bo tier n est pas ferm e l aide des quatre broches tel qu indiqu ci dessous Soyez extr mement prudent lorsque vous utilisez le rotateur des vitesses de rotation sup rieures 2000 tr min
147. tion maintains an online support page for the rotator at the following URL http www voltammefitry net pine msr 1 2 Copyright This publication may not be reproduced or transmitted in any form electronic or mechanical including photocopying recording storing in an information retrieval system or translating in whole or in part without the prior consent of Pine Research Instrumentation Inc in writing 1 3 Trademarks WaveDriver WaveNow WaveNano and AfterMath are registered trademarks of Pine Research Instrumentation Inc Durham NC All other trademarks are the property of their respective owners 1 4 Use Limitation The MSR rotator is not designed for use in experiments involving human subjects and or the use of electrodes inside or on the surface of the human body Any use of this instrument other than its intended purpose is prohibited DRU10002 REV 002 APR 2015 1 5 Service and Warranty Information For questions about proper operation of the MSR rotator or other technical issues please use the contact information below to contact Pine directly TECHNICAL SERVICE CONTACT Pine Research Instrumentation Inc www pineinst com echem Phone 1 919 782 8320 FAX 1 919 782 8323 If the MSR rotator or one of its Components or accessories must be returned to the factory for service please contact Technical Service see above to obtain a Return Material Authorization RMA form Include a copy
148. to connect the control unit to the motor unit Note that two or three of these cables may be connected in series to allow for a greater distance between the control unit and the motor unit Description Part Number Motor Control Cable EWC15DSUB Precision Shaft Alignment Kit This kit contains a dial indicator with mounting apparatus used measure the runout af the bottom end of the shaft instructions for use are included with the kit Description Part Number Precision Shaft Alignment Kit AKDIAL DRU10002 REV 002 APR 2015 110 Figure 7 1 Standard C18 Connection on Power Entry Module 7 2 Power Cords The power entry module on the back panel of the control unit accepts any power cord compatible with a standard C18 plug see Figure 7 1 A wide range of power cord options are described below This cord is for use in the USA Canada This cord is for use in continental Europe Mexico Brazil Columbia Korea Mexico Russia and Indonesia Saudi Arabia and Taiwan Description Part Number Description Part Number Power Cord USA cccccssssssssteeeeees EWM18B7 Power Cord Europe EWM18B8EU This cord is for use in the United Kingdom This cord is for use exclusively in China Ireland Oman Hong Kong and Singapore Description Part Number Description Part Number Power Cord UK EWMI18B8UK Power Cord Ching ccseeceeees EWM18B8CN h eee er fs RESEARCH INSTRUMENTATION
149. ts provide separate cable connections for the working electrode drive line and for the working ly electrode sense line The drive line carries current while the sense line measures the potential Both of these lines must be connected to the rotating electrode brushes Note that many older potentiostats use only one cable to carry both the drive and sense signals for the working electrode Note Cell cables on newer model Pine potentiostats use RED to mark the working electrode drive line and ORANGE to mark the working electrode sense line Both of these should be connected to the rotator brushes see Figure 4 8 bai Note Older Pine bipotentiostats use only one cable connection for both the drive and the sense signals This connection is marked with a YELLOW banana jack on the bipotentiostat front panel L Tip There is no universally accepted color coding scheme for marking potentiostat cell cable connections If you are using the rotator with a third party potentiostat consult the potentiostat documentation for information about the cell cable markings 4 4 2 RRDE Wiring The lower pair of brush contacts are only used with a rotating ring disk electrode see Figure 4 9 The lower pair of brushes blue contacts the ring electrode while the upper pair red contacts the disk electrode Banana jumper cables are used to short together the opposing brushes in each pair to ass
150. upteur de l unit de commande est en position teinte et que le bouton de commande de la vitesse de rotation est compl tement tourn dans la position inverse des aiguilles d une montre Reconnect the motor control cable from the control unit fo the motor unit Reconnect the power cable from the power source to the control unit 7 on DRU10002 REV 002 APR 2015 RESEARCH INSTRUMENTATION N 36 Figure 4 3 Proper left and Improper right Shaft Insertion Positions A WARNING Do not turn on the rotator or rotate the electrode shaft if the shaft is not securely mounted in the motor coupling Inspect the shaft to be certain that it is securely mounted AVERTISSEMENT Ne mettez pas le rotateur en marche ni l arbre de I lectrode en rotation si l arbre n est pas correctement raccord au moteur Inspectez l arbre pour vous assurer qu il est bien fix With the rotation rate knob in the fully counterclockwise position turn on the control unit Slowly turn the rotation rate knob clockwise until the shaft rotates between 100 and 200 RPM While the shaft is slowly rotating 100 to 200 RPM inspect the rotating shaft to assure that if is rotating properly about the axis of rotation If the shaft is wobbling vibrating or tilting away from the axis of rotation then turn off the rotator and remove the shaft from the rotator Note 1 A Precision Shaft Alignment Kit is available separately This k
151. ure good contact with both sides of the rotating shaft DRU 10002 REV 002 APR 201 48 Tip It is possible that the brush assemblies on a rotator that has been in use for some time may have been replaced or swapped and thus the colors of the brushes may not be as described in the previous paragraph or as shown in Figure 4 9 The important concept to remember is that the UPPER pair of brushes contacts the disk electrode and the LOWER pair of brushes contacts the ring electrode Figure 4 9 Brush Connections for a Rotating Ring Disk Electrode RRDE Tip A bipotentiostat is required when working with a rotating ring disk electrode A bipotentiostat provides independent control of two different working electrodes in the same electrochemical cell Note Cell cables on newer model Pine bipotentiostats use RED and ORANGE to mark the first working electrode drive and sense lines respectively Both of these cables must be connected to the UPPER pair of electrode brushes red to contact the disk Cell cables on newer model Pine bipotentiostats use BLUE and VIOLET to mark the second working electrode drive and sense lines respectively Both of these cables must be connected to the lower pair of electrode brushes blue to contact the ring 49 Note Older Pine bipotentiostats use only one cable for both the drive and the sense signals The YELLOW connection corresponds to the disk and the BLUE connecti
152. ured with a ratio of 1 0 RPM mV because this ratio is compatible with Pine potentiostat systems WARNING Risk of electric shock Disconnect all power before servicing the rotator AVERTISSEMENT Risque de d charge lectrique D connectez toutes les sources d alimentation avant de proc der l entretien du rotateur CAUTION A Static electricity may damage electronic components Ensure proper grounding when handling static sensitive components by wearing a grounding strap ATTENTION L lectricit statique est susceptible d endommager les composants lectriques Veillez disposer d une mise la terre appropri e lorsque vous manipulez des composants sensibles en portant un ruban de mise la terre With the power cord disconnected remove the cover from the control unit SINE DRU10002 REV 002 APR 2015 102 Loosen the screw that secures the main analog board to the front panel and On the board locate the configuration pins with the designation JP2 There is a small jumper that can be used to short together one of three pairs of pins 5 E e Yes Can sees Place the jumper across one of the three pairs of pins at JP2 Choose the ratio required for the particular potentiostat being used with the rotator JP2 1 RIS es il Le GR1o 1 0 RPM mV 2 0 RPM mV 4 0 RPM mV Note MSR rotator factory setting is 1 0 RPM mV 103 R
153. ush Kit ACARO63RM Low Humidity Brush Kit ACARO63RMLHM Complete Brush Assembly To replace an entire brush assembly order one of the parts below This complete assembly includes the brush holder a color coded banana jack and a spring loaded brush contact already mounted in the assembly Description Part Number Brush Assembly blue ACMR3298XB Brush Assembly red ACMR3298XR Brush Assembly yellow ACMR3298XY Brush Assembly green ACMR3298XG Motor Coupling Assembly The motor motor coupling and mounting flange are sold together as one single unit Note that if is not possible to purchase these three items separately Description Part Number Motor Coupling Assembly ACMR3165CE Motor Coupling Hex Screws This kit includes ten 10 replacement hex screws for use with the motor coupling A pair of these screws is used fo secure the rotating shaft inside the motor coupling This kit also includes the hex key tool required to tighten these screws Description Part Number Motor Coupling Hex Screw Kit AKMRHEX DRU10002 REV 002 APR 2015 108 Lower Bearing Assembly The lower bearing assembly stabilizes the rotating shaft af the point where the shaft exits the brush chamber The standard assembly has a stainless steel bearing A special assembly with a ceramic bearing Is available for use in corrosive environments Description Part Number
154. ver carbon brushes fo contact metal surfaces on the upper portion of the rotating shaft Each shaft is soecially designed to provide one or two current paths down to the electrode tip These current paths are electrically isolated from the mounting area at the top of the shaft Ta insulator m or ia contact area OOOO insulator ring contact area gt Figure 4 1 Contact Areas at Top of Rotating Electrode Shafts DRU10002 REV 002 APR 2015 32 The uppermost portion of the shaft is used to mount the shaft into the rotator see Figure 4 1 This mounting area is electrically isolated from the remainder of the shaft so that the electrode connections remain isolated from the rotator chassis An insulating soacer just below the mounting area Isolates the mounting area from the electrode contact area For an RDE or RCE shaft see Figure 4 1 left the entire metal exterior of the shaft below the insulating spacer is in electrical contact with the disk or cylinder electrode For an RRDE shaft see Figure 4 1 right there are two insulating spacers The portion of the shaft between the two insulating spacers provides electrical contact with the disk electrode The lower portion of the shaft below the lower insulating spacer provides electrical contact with the ring electrode Figure 4 2 The Brush Chamber side view The shaft is connected to the rotator motor via a brass motor coupling located inside the
155. vous assurer qu il n a pas t endommag DRU10002 REV 002 APR 201 WARNING Do not use or attempt to rotate an electrode tip that has been dropped or otherwise physically damaged Inspect the electrode tip to be certain that it is not damaged AVERTISSEMENT N utilisez pas et ne tentez pas de mettre en rotation un embout d lectrode qui est tomb e ou a t endommag e physiquement d une autre mani re ou d une autre Inspectez l embout d lectrode pour vous assurer qu elle n a pas t endommag e WARNING Do not use an electrode shaft which appears to wobble vibrate or tilt away from the axis of rotation while rotating Such a shaft is either improperly installed or physically damaged Turn off the rotator disconnect electrical power and remove the shaft immediately AVERTISSEMENT N utilisez pas un arbre d lectrode qui semble osciller vibrer ou d vier de l axe de rotation pendant la rotation Cet arbre est soit install de mani re incorrecte soit endommag physiquement teignez le rotateur d connectez l alimentation lectrique et retirez l arbre imm diatement WARNING Do not use an electrode tip which appears to wobble vibrate or tilt away from the axis of rotation while rotating Such an electrode tip is either improperly installed or physically damaged Turn off the rotator disconnect electrical power and remove the electrode tip immediately AVERTISSEMENT N uti
156. xis i e to infinite rotation rate yields a zero intercept This is the identical result obtained for a facile half reaction see Figure 10 8 right because these currents are sampled at a high enough overpotential that there are no kinetic limitations Only mass transport limits the current and the usual Levich behavior applies However for the two sets of currents sampled on the rising portion of the voltammogram see Figure 10 9 blue triangles and purple squares the extrapolation back to the vertical axis yields non zero intercepts This non zero intercept indicates a kinetic limitation meaning that even if mass transport were infinite i e infinite rotation rate the rate of the half reaction would still be limited by the slow kinetics at the electrode surface The linear portion of the data on a Koutecky Levich plot is described by the Koutecky Levich equation 1 1 1 2 gt 2 3 1 6 w l Le 0 620n FAD v C Plotting the reciprocal current 1 against the reciprocal angular rotation rate wt yields a straight line with an intercept equal to the reciprocal kinetic current ik The kinetic current is the current that would be observed in the absence of any mass transport limitations By measuring the kinetic Current at a FINE RESEARCH INSTRUMENTATION 5 135 variety of different overpotentials along the voltammogram it is possible to determine the standard rate constant for the electrochemical half reacti
157. xperience J Appl Electrochem 15 1985 807 38 DR Gabe and PA Makanjuola Enhanced Mass Transfer Using Roughened Rotating Cylinder Electrodes in Turbulent Flow J Appl Electrochem 17 1987 370 FINE RESEARCH INSTRUMENTATION 5 39 40 4 42 43 44 45 46 47 48 49 50 51 92 53 54 co 56 5 58 59 60 FINE RESEARCH INSTRUMENTATION 5 143 DR Gabe GD Wilcox J Gonzalez Garcia and FC Walsh The Rotating Cylinder Electrode Its Continued Development and Application J Appl Electrochem 28 1998 759 G Kear BD Barker K Stokes and FC Walsh Flow Influenced Electrochemical Corrosion of Nickel Aluminum Bronze Part I Cathodic Polarization J Appl Electrochem 34 2004 1235 G Kear BD Barker K Stokes and FC Walsh Flow Influenced Electrochemical Corrosion of Nickel Aluminum Bronze Part Il Anodic Polarization and Derivation of the Mixed Potential J Appl Electrochem 34 2004 1241 Q Lu MM Stack and CR Wiseman AC Impedance Spectroscopy as a Technique for Investigating Corrosion of Iron in Hot Flowing Bayer Liquors J Appl Electrochem 31 2001 1373 JM Maciel and SML Agostinho Use of a Rotating Cylinder Electrode in Corrosion Studies of a 90 10 Cu Ni Alloy in 0 5M H2SO4 Media J Appl Electrochem 30 2000 981 JM Grau and JM Bisang Mass Transfer Studies at Rotating Cylinder Electrodes of Expanded Metal J Appl Electrochem 35 2005 285 A Eklund and
158. y 24 25 taper 15 mm ID bearing ee eeeeeeeeeee ACOITPAGM 65 Simple Taper Plug Assembly 6 35 mm ID This bearing assembly fits into the 24 25 center port on an electrochemical cell The main body of the assembly is made from Teflon and the internal diameter of the opening in the stainless steel bearing is 6 35 mm This 6 35 mm ID opening is compatible with the standard RDE and RCE shaft part number AFE3M and with E2 Series single piece RDEs This bearing assembly does not perfectly seal the electrochemical cell Description Part Number Simple Taper Plug Assembly 24 25 taper 6 35 mm ID bearing eeeeseseeeeeeeceeceseeeeeeees ACOITPA DRU10002 REV 002 APR 20 66 5 3 RDE Tips The rotator is compatible with a variety of RDE tips sold separately and each tio design is compatible with one or more shafts as described below E3 Series RDE Tips These RDE tips feature a 12 mm OD Teflon shroud around a 5 mm OD disk electrode These tips fit the standard RDE shaft and may be used af rotation rates up fo 2500 RPM Standard disk materials include gold platinum and glassy carbon Other disk and shroud materials are available upon request Description Part Number Standard RDE Shaft for 12 mm OD RDE tips ccscscsscsssenstecteiestanateonseirshetsastiacstairiassesntacntuintaenseanterss AFE3M Glassy Carbon RDE tip 5 mm OD disk 12 MM OD shroud UN AFE3TOS0GC Basal Plane Pyrolytic Graphite RDE tip 5 mm OD disk 12 mm
159. y to use active HIGH logic If desired a jumper setting inside the control box can be configured fo use the opposite logic see Section 6 8 for details If The MOTOR STOP logic is configured to be active HIGH then the motor is allowed to rotate if a signal greater than 2 0 volts is applied across the MOTOR STOP banana jacks If the two banana jacks are shorted together i e if the MOTOR STOP stop signal is driven to ground then the motor stops rotating If The MOTOR STOP logic is configured to be active LOW then the motor will stop If a signal greater than 2 0 volts is applied across the MOTOR STOP banana jacks If the two banana jacks are shorted together i e if The MOTOR STOP signal is driven to ground then the motor is allowed fo rotate Note C When the control unit is configured for active HIGH logic and l when no connections are made to the MOTOR STOP banana jacks the motor is allowed to rotate An internal pull up circuit assures that the motor stop signal remains high in this case DRU 10002 REV 002 APR 2015 58 4 8 Circuit Protection The power switch on the back panel also acts as a circuit breaker to help protect the control unit circuitry If the circuit breaker trips then if can be reset by turning the power switch to the full off position and then turning the switch back on again A secondary circuit breaker on the front panel protects the windings in

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