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Keysight Agilent HP 6433B Datasheet

1. 33k 4 CURRENT CONTROL iu CONSTANT CURRENT 2 5 INPUT IECUIT CIECO i P C20 CR30 NEA OV A4 KD T 45391 47 ex A8 _ Seid PA OV EWH A9 4 642273 e e ____ VOLTAGE CONTEO RV GS CONTROL LS SCR REGULATOR us CONTROL CKT 43K t vel gt gt gt CHO c3 00224 200Y SCHEMATIC 0 32V 0 10A HARRISON Berkeley Heights N J Div of Hewlett Packard 4410 as NOTE Ate RESISTORS W 57 UNLESS NOTED ZF SELECTED FOR OPTIMUM 2 MH DENOTES ZO PPM WIPE TEMP COEFF 5 REAR TEEMINALS SHOWN NOGMAL STEAPPING 4 INPUT VOLTAGES MEASURED IBV NO LOAD PATENT APPLIED ON THIS LICENSE OSE MUST BE OBTAINED IN WRITING From HABZISON LA amp ozAToZI amp e Dw HEWLETT 5 DENOTES VOLTAGE SIGNAL 6 DENOTES SIGNAL N 3 5 m KNINA 5 amp 9 M 3 EISE N 4 x 5 amp HEWLETT 0 PACKARD HARRISON DIVISION il The information contained in this booklet is intended for the operation and mainte nance of Harrison equipment and is not to be reproduced without written consent of Harrison Div
2. nal A X 8 c Gm Cue m H BM MH BE EE s 2 carm ems Section IV TABLE OF CONTENTS cont Title PRINCIPLES OF OPERATION oo 4 1 Block Diagram Description 4 9 Circuit Description 4 10 AC Input 4 12 DC Output 4 14 Voltage Input 4 20 Current Input 4 24 Gating Circuit 4 27 Turn On Circuit 4 29 SCR Regulator Control 4 37 SCR Regulator 4 42 Bias and Reference Circuit AINTENANCE 1 General 3 Measurement Techniques oe n 7 Performance Check o o 8 General 10 Rated Output and Meter Accuracy 13 Line Regulation 5 16 Load Regulation 5 19 Ripple and Noise 5 21 Transient Recovery Time 5 23 Additional Specification Check 5 24 Temperature Coefficient e 5 27 Output Stability 5 30 Remote Programming o gt o 5 33 Output Impedance gt o 5 35 Output Inductance 5 37 Cover Removal 5 39 Troubleshooting 5 40 General e o o o o o o ooo o o oo 5 42 Trouble Analysis e o 5 49 Repair and Replacement 5 51 Adjustments and Calibrations 9 52 1 5 54 Meter Zero 5 56 Voltmeter Tracking 5 58 Ammeter Tracking s o 5 60 Constant Voltage Program
3. not separately replaceable MANUFACTURERS AB Allen Bradley Kulka Kulka Electric B Bendix Corporation Mot Motorola Inc Beede Beede Elec Instr Co Inc RCA Radio Corporation of America Buss Bussman Mfg Company Reliance Reliance Mica Corporation Carling Carling Electric Company Mica CTS CTS Corporation Semcor Semcor Corporation Elco Elco Corporation Sloan Sloan Company GE General Electric Company Sprague S prague Electric GI General Instrument Company Superior Superior Electric HH Hardwick Hindle Company Sylv Sylvania Electric Hoff Hoffman Electric Company TI Texas Instruments WL Ward Leonard Electric TA X 06 00 1061 TN STV PAN 6 2610 0910 4910 0910 1620 0810 8100 0910 80560 806560 6 02226 68295 68295 6829S 6829S 6829S 6829S 680965 68295 6829S 68295 68295 x9poD JN T5 i 0p V 15 8020 15111 ATAS 6 5 8 46 22426 66 68d 6T pad 620 O90T 06 2949606 501 GOST 0929 I onbeudg 2906 omedd g 050 Td TOT g 6 01409 262274261 pad 900 enbeudg 9401 08 Wed 91 r m NN 202222 Aud OS VOZ 5 Jegnoeu 7 07 6180 So vr Frc 002 WL YOS LIND 15 05 6 9 272 1 Add OT
4. OPERATION 3 4 GENERAL 3 5 The power supply is designed so that its mode of operation can be selected by making strapping connections between particular terminals on the terminal strip at the rear of the power supply The terminal designations are stenciled in white on the power supply and are adjacent to their respective terminals The strapping patterns illustrated in this section show neither terminal grounded The operator can ground either terminal or operate the power supply up to 300 vdc off ground floating 3 6 NORMAL 3 7 GENERAL The power supply is normally shipped with its rear terminal strapping connections arranged for constant voltage constant current local sens ing local programming single unit mode of operation This strapping pattern is illustrated in figure 3 2 The operator selects either a constant voltage or a constant current output using the front panel controls local programming no strap ping changes are necessary 3 8 CONSTANT VOLTAGE To select a constant voltage output proceed as follows a Turn on power supply and adjust VOLTAGE controls for desired output voltage output terminals open b Short output terminals and adjust CURRENT controls for maximum output current allowable current limit as determined by load conditions If a load change causes the current limit to be exceeded the power supply will automatically cross over to constant current output at the preset current limit and the
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6. 595 10 w Measure impedance Capacitor 500 50 vdcw Measure impedance Oscillator Range 1 cps to 100 Measure impedance HP 202C Accuracy 296 Output 10 vrms 4 8 Table 5 1 Test Equipment cont Required Recommended Characteristics Model Controlled temperature Range 0 509C Measure tempera oven ture stability Resistance box Range 0 6 400 ohms Measure program H Lab 69312 Accuracy 0 1 plus ming coefficients ohm Make before break contacts NOTE 1 A satisfactory substitute for a differential volt meter is td arrange a reference voltage source and null detector as shown in figure 5 1 The reference voltage source is adjusted so that the voltage difference between the supply being measured and the reference voltage will have the required resolution for the measurement being made The voltage difference will be a function of the null detector that is used For measure ments at the base of transistor CM a null detect or with input impedance of 10 megohms or great er is required Otherwise satisfactory null detectors are HP 405AR digital voltmeter HP412A dc voltmeter HP 419A null detector a dc coupled oscilloscope utilizing differential input or a 50 mv meter movement with a 100 division scale A 2 mv change in voltage will result in a meter de flection of four divisions CAUTION Care must be exercised when using an electronic null detector in which one input terminal is gro
7. 9 ESZENT WOOCINT 10 ay a SHH AUN 002 009 7 1 ASF AO 2 KSF 9097 2 7 NOTI pxj 7 1 6 5 duloo pxj 7 7 6 duoo peubtssy 10N 2 1 SSF 594089 pxj SF 708 t 006 MM WA SF MM 194 YOOT 2 1 ASF 00 pxj 8 1 AIF px 8 1 PIF VAZI 8 1 AIF VNOOI WTH PXJ 8 1 AIF VHEP WIT SF MM IVA 8 1 AIF 200 UOOHIS 5 5 7575 uocTITs 7876 291111 171050 WOT esnd 1ubrT 1o3e2rppur UOOHIS Jepgnoey 001 5 JermnoewW uondrploseq JoqunN 8 vv 66 40i 91 GU LY 9 98 02 SY 61 Zu 010 Tt 40 6 8 9 TSA 02 0 eouelejey 6433A 6 4 e NNN C9 0706 2061 2940 2061 6266 2061 5066 9890 502 9890 6181 9890 9667 9890 5501 9890 5951 9390 5951 9890 L0 4S 40 6640 4540 5202 989
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9. 4 23 8 09 OUTPUT Resistor R13 is the collector load for Q8 The collector output of Q8 is coupled to the gating circuit Voltage divider R20 R46 biases the base of Q9 and maintains a slightly negative base bias to ensure that the output current can be programmed to zero Resistor R44 provides positive feedback to improve load regulation during constant current operation 4 24 GATING CIRCUIT 4 25 Transistor Q4 draws current from the SCR control circuit capacitor C25 The magnitude of this current is determined by either the voltage or current input circuit For constant voltage operation diode CR7 is forward biased to permit the voltage input circuit to drive Q4 diode CR8 is reverse biased to inhibit the input from the current input circuit For constant current operation the reverse occurs 4 26 prevent transients in the dc output when the power supply is turned on the turn on of Q4 is delayed by capacitor C2 which charges through R12 R15 and CRS When C2 charges sufficiently to reverse bias CR5 all the current through R15 flows to the base of Q4 to turn it on This base current is controlled by the voltage or current input circuits via CR7 or CR8 respectively For example during constant voltage operation the collector voltage of Q1 voltage input forward biases CR17 CR8 reverse biased by Q8 the current through CR7 will vary as Q1 collector volt age varies and thus vary base current therefore the collector current of
10. CURRENT Proceed as follows a Connect test setup shown in figure 5 3 b Turn front panel VOLTAGE controls fully clockwise maximum c Turn front panel CURRENT controls until front panel ammeter indicates 10 amperes d Record voltage indicated on differential voltmeter e Close the shorting switch f Differential voltmeter indication should change by less than 0 5 mvdc 9 19 RIPPLE AND NOISE 9 20 Proceed as follows a Connect the 3 2 ohm load resistor across the output terminals and the ac voltmeter across the 5 and S terminals b Turn front panel CURRENT controls fully clockwise maximum C Connect the variable voltage transformer between the input power source and the power supply power input Adjust the variable voltage transformer to 125 vac 4 Turn front panel VOLTAGE controls until front panel ammeter indicates lOamperes e The ac voltmeter should indicate less than 32mvrms 5 4 5 21 TRANSIENT RECOVERY TIME 9 22 Proceed as follows a Connect test setup shown in figure 5 4 b Turn front panel CURRENT controls fully clockwise maximum C Turn front panel VOLTAGE controls until front panel ammeter indicates 10 amperes d Open and close the switch several times and observe the oscilloscope display Oscilloscope display should be as shown in figure 5 5 OSCILLOSCOPE 130C NOTE OSCILLOSCOPE MUST BE DC COUPLED REX FIGURE 5 4 TRANSIENT
11. QA is controlled by the voltage input In a similar manner the current input circuit controls the collector current of Q4 during constant current operation 4 27 TURN ON CIRCUIT 4 28 Transistor Q3 provides a path for rapidly discharging C2 in gating circuit when the power supply is turned off This assures that C2 is discharged if the power supply is turned on shortly after turn off The purpose of having C2 dis charged each time the power supply is turned on is to maintain the same time delay in the turn on of the gating circuit refer to para 4 26 4 29 SCR REGULATOR CONTROL See waveshapes on figure 4 2 4 30 GENERAL The SCR regulator control is basically a blocking oscillator Q7 and T3 that applies pulses to the SCR regulator in response to error signals detect ed by the voltage or current input circuit When transistor Q7 conducts the pulse developed in winding 1 2 of transformer T3 is coupled to the base of Q7 positive feedback and to the SCR regulator CR17 and CR18 Capacitor C27 charges in op position to the feedback voltage and cuts off Q7 The charge time of C27 determines the pulse duration in the collector of Q7 approximately 20 microseconds The 35 vdc bias supplies current through R52 CR46 and CR44 to discharge C27 after Q7 Stops conducting 4 31 Throughout the operation of the blocking oscillator capacitor C25 supplies most of the collector current for Q4 in the gating circuit refe
12. cur rent may exceed their maximum ratings and re sult in damage to the load The power supply will not be damaged 3 16 Proceed as follows a Turn off power supply and arrange rear terminal strapping pattern as shown figure 3 3 The sensing wires will carry less than 10 ma and need not be as heavy as the load wires It is recommended that sensing and load wires be twisted and shielded If shield is used connect one end to power supply negative terminal and leave the other end unconnected CAUTION Observe polarity when connecting the sensing leads to the load b In order to maintain low ac output impedance a capacitor with a mini mum rating of 20 000ufd and 25 vdcw should be connected across the load using Short leads This capacitor must have high frequency characteristics as good or better than C17 has see parts list C Turn on power supply 3 17 REMOTE PROGRAMMING 3 18 GENERAL The constant voltage and constant current outputs may be pro grammed controlled from a remote location The front panel controls are disabled in the following instructions Changes in the rear terminal strapping arrangement are necessary The wires connecting the programming terminals of the power supply to the remote programming device should be twisted or shielded to reduce noise pick up if shield is used connect one end to power supply ground terminal and leave the other end unconnected Remote sensing para 3 14 may be used sim
13. current exceeds a preset limit This crossover circuitry also protects the load from overvoltage during constant current operation by automatically switching the power supply into constant voltage operation The user can adjust the crossover point via the front panel controls para 3 8 and 3 9 1 6 The power supply is protected from reverse voltage positive voltage applied to negative terminal by a diode that shunts current across the output terminals when this condition exists The ac input is fused A double pole on off switch opens both power leads in the off position 1 7 COOLING 1 8 Convection cooling is used No fan is required The power supply has no moving parts except meter movement 1 9 MONITORING 1 10 Two front panel meters are provided for monitoring output voltage and current The voltmeter has a 0 to 40 volt range and the ammeter has a 0 to 12 ampere range Each meter has 2 accuracy at full scale 1 11 OUTPUT TERMINALS 1 12 Output power is available via a terminal strip on the rear panel The rear panel terminal strip also enables the power supply to be connected for different modes of operation para 3 3 The output terminals are isolated from the chassis and either the positive or the negative terminal may be connected to the chassis via a separate ground terminal located adjacent to the output terminals The power supply is insulated to permit operation up to 300 vdc off ground 1 13 INSTRUMENT ID
14. f Raise the temperature to 40 C and allow a half hour warm up Differential voltmeter indication should change by less than 1 5 mvdc from indication recorded in step e 9 27 OUTPUT STABILITY 5 28 CONSTANT VOLTAGE Proceed as follows 5 6 a Connect the 3 2 ohm load resistor across the output terminals and the differential voltmeter across the S and 45 terminals b Turn front panel CURRENT controls fully clockwise maximum Turn front panel VOLTAGE controls until the differential voltmeter indi cates 32 vdc d allow a half hour warm up and then record the differential voltmeter in dication e After eight hours the differential voltmeter indication should change by less than 72 mvdc from indication recorded in step d 5 29 CONSTANT CURRENT Proceed as follows a Connect test setup shown in figure 5 3 b Turn front panel VOLTAGE controls fully clockwise maximum C Turn front panel CURRENT controls until the differential voltmeter indi cates 50 mvdc d Allow a half hour warm up and then record the differential voltmeter indication e After eight hours the differential voltmeter indication should change by less than 0 5 5 30 REMOTE PROGRAMMING 5 31 CONSTANT VOLTAGE Proceed as follows a Turn off power supply and arrange rear terminal strapping pattern for constant voltage remote programming as shown in figure 3 4 use the resistance box set to 2 000 ohms for the remote prog
15. output the secondary of transformer is full wave rectified by bridge rectifier CR19 through CR22 and filtered by pi section filter C13 C17 and L1 Resistor R29 damps the parallel resonance of L1 and C17 The dc output is regulated to a constant value by the SCR s in the ac input line Capacitor C17 is the output capacitor Diode CR23 is connected across the filtered dc output to protect the power supply from reverse voltage applied to the output terminals Resistor R23 is the current monitoring resistor the full load current flows through it Resistors R25 and R27 are used to calibrate the voltmeter and ammeter respectively 4 14 VOLTAGE INPUT 4 15 GENERAL The voltage input circuit is basically a differential amplifier 01 02 that detects any voltage difference between the programmed output voltage and the actual output voltage The differential amplifier output voltage varies in proportion to the power supply output voltage vaiiation 4 16 Q2 INPUT Voltage divider R6 R47 maintains a slightly negative base bias to ensure that the output voltage can be programmed to zero The output of Q2 is emitter coupled resistor R4 to Q1 4 17 Ql INPUT There are three inputs to the base of Q1 one determined by the programmed voltage voltage controls R2 R8 the second determined by the collect or voltage of Q1 negative feedback and the third is from the positive side of the main rectifier The collector current of Q1 is determi
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17. 1 0 ohm OUTPUT INDUCTANCE Proceed as follows a Repeat steps a through c of para 5 34 b Adjust the oscillator for 10 vrms Ein 10 kc output C Calculate and record the output inductance using the following formula L Xj 2fff 5 9 X is the output impedance Zout calculated in steps and f of paragraph 5 34 f is the frequency of the oscillator determines which 2 is used NOTE The equation assumes tha Xj Rgy and therefore X Zout d Using the formula given in step c calculate and record the output induc tance for oscillator frequencies of 50 kc and 100 kc at 10 vms e The output inductance calculated in steps c and d should not exceed 1 0 microhenry 5 37 COVER REMOVAL S 38 The top and bottom covers are removed by removing both sets of six attaching screws 9 39 TROUBLESHOOTING 9 40 GENERAL 5 41 If a fault in the power supply is suspected remove the covers para 5 38 and visually inspect for broken connections burned components etc If the fault is not detected visually proceed to trouble analysis para 5 42 If the fault 1s detected visually or via trouble analysis correct it and then do the performance check para 5 7 If a part is replaced refer to repair and replacement para 5 50 and to adjustments and calibrations para 5 51 9 42 TROUBLE ANALYSIS 5 43 GENERAL Before attempting trouble analysis a good understanding of the principles of operation should be acquire
18. 2 3 4 8 9 from 2N3390 to 2113391 Corporate Part 1854 0071 Table 1 1 INPUT RATED OUTPUT LINE REGULATION LOAD REGULATION RIPPLE AND NOISE OPERATING TEMPERATURE RANGE STORAGE TEMPERATURE RANGE TEMPERATURE COEFFICIENT OUTPUT STABILITY after 30 minute warm up REMOTE PROGRAMMING TYPICAL OUTPUT IMPEDANCE OUTPUT INDUCTANCE Specifications 105 125 vac 57 to 63 cps single phase 7 amperes 450 watts max Constant Voltage 0 to 32 vdc Constant Current 0 to 19 amperes dc Constant Voltage Less than 18 mv for 105 125 vac input change Constant Current Less than 100ma for 105 125 vac input change Constant Voltage Less than 36mv for 0 to 10ampere load change Constant Current Less than 100 ma for 0 to 32vdc load change 32 mvrms 00C to 50 C 209C to 719C Constant Voltage 0 05 plus 8 mv per degree centigrade Constant Current 30 per degree centigrade Constant Voltage 0 1596 plus 24mv for 8 hours at constant temperature Constant Current l00ma for 8 hours at constant temperature Constant Voltage 200 ohms per volt 1 Constant Current 250hms per ampere 41096 Less than 0 01 ohm from dc 0 5 cps Less than 0 5 ohm from 0 5 cps to 100 cps Less than 0 2 ohm from 100 cps to lke Less than 1 0 ohm from to 100 kc 1 0 microhenry Table 1 1 Specifications cont TRANSIENT RECOVERY TIME In constant voltage operation less than 300 millisec
19. A4 S 8 AS MASTER MUST BE MOST NEG ATIVE SLAVE I FIGURE 3 11 AUTO TRACKING STRAPPING PATT ERN SLAVE 2 WVH9VIQ 0078 1 3uno9i3 LINDYID NO NUNL 11194819 LAdNI ASVLIOA YAWYOS 1 09 Hos 1515 38 9NI YOLINOW LNAYYND JO1V1938 805 HOJV1n93U 495 9v 5 NIV 831113 8 831311238 NIV IOYLNOD LN3YYND 019 6Y MIO 39 393334 8 5718 LINDYID Afi dNI LNAYYND SECTION IV PRINCIPLES OF OPERATION 4 1 BLOCK DIAGRAM DESCRIPTION See figure 4 1 4 2 The main power transformer isolates the ac input from the power supply and reduces it to the voltage level required Rectification and filtering produces a smoothed dc output across the and terminals large capacitor is connect ed across the and 4 terminals for low ac output impedance and to help supply large pulse currents An SCR regulator controls the ac input to provide good regulation of the dc output The auxiliary power transformer powers the SCR regulator control circuit and the bias and reference circuit which produces dc bias and reference voltages for the power supply 4 3 The SCR regulator is controlled by the SCR regulator control circuit which operates in response to signals developed by the voltage or current input circuit gating circuit assures that on
20. AL CHECK 2 7 Check that the straps on the terminal strip at the rear of the power supply are secure and that the strapping pattern 1s in accord with figure 3 2 Check the electrical performance of the power supply as soon as possible after receipt performance check that is suitable for incoming inspection is given in paragraphs 5 7 through 5 22 2 8 INSTALLATION DATA 2 9 GENERAL 2 10 The power supply is shipped ready for bench or relay rack 19 inch operation 2 11 LOCATION 2 12 Because the power supply is cooled by convection there must be enough space along the sides and rear of the power supply to permit free flow of cooling air The power supply should be located in an area where the ambient temperature does not exceed 50 C 2 13 POWER REQUIREMENTS The power supply is operated from a 105 to 125 volt 115 volts nominal 2 14 At 115 volts 60 cps the full load re 57 to 63 cps single phase power source quirement is 450 watts at 6 5 amperes 2 15 POWER CABLE 2 16 To protect operating personnel the National Electrical Manufacturers Association NEMA recommends that the instrument panel and cabinet be grounded This instrument is equipped with a three conductor power cable The third conduct or is the ground conductor and when the cable is plugged into an appropriate receptacle the instrument is grounded The offset pin on the power cable three prong connector is the ground connection 2 17 To p
21. ENTIFICATION 1 14 Harrison Laboratories power supplies are identified by a three part designa tion The first part is the model number the second part is the serial number and the third part is the manufacturing code letter This manual applies to all Model 6433A power supplies with the same manufacturing code letter given in the title page Change sheets will be supplied with the manual to make it apply to Model 6433A power supplies with different manufacturing code letters 1 2 SECTION II INSTALLATION 2 1 INITIAL INSPECTION 2 2 GENERAL 2 3 Before shipment the power supply was inspected and found free of mechan ical and electrical defects If damage to the shipping carton is evident ask that the carrier s agent be present when the power supply is unpacked As soon as the power supply is unpacked inspect it for any damage that may have occurred in transit Also check the cushioning material for signs of severe stress may be indication of internal damage Save all packing materials until the inspection is completed If damage is found proceed as instructed in the Claim for Damage in Shipment notice on the back of the front cover of this manual 2 4 MECHANICAL CHECK 2 5 Check that there are no broken knobs or connectors that the external sur face is not scratched or dented that the meter faces are not damaged and that all controls move freely Any external damage may be an indication of internal damage 2 6 ELECTRIC
22. Errata Title amp Document 6433B DC Power Supply Module Operating and Service Manual Manual Part Number 06433 90001 Revision Date J anuary 1966 About this Manual W e ve added this manual to the A gilent website in an effort to help you support your product This manual provides the best information we could find It may be incomplete or contain dated information and the scan quality may not be ideal If we find a better copy in the future we will add itto the A gilent website HP References in this Manual This manual may contain references to HP or Hewlett Packard Please note that H ewlett Packard s former test and measurement life sciences and chemical analysis businesses are now part of A gilent Technologies The HP XXXX referred to in this document is now the Agilent XX X X For example model number HP8648A is now model number A gilent 8648A We have made no changes to this manual copy Support for Your Product A gilent no longer sells or supports this product Y ou will find any other available product information on the A gilent Test amp M easurement website www agilent com Search for the model number of this product and the resulting product page will guide you to any available information Our service centers may be able to perform calibration if no repair parts are needed but no other support from A gilent is available NE Agilent Technologies OPERATING AN D SERVICE MANUAL MODEL 6433B DC POWER
23. HOA 07 0 92224 JOIOW 140141 sumo og eur 1919 ding dns Jerueg ex onm C san Y e JoqunN t 6433A 6 6 Test Points 31 33 5 usec cm 5v cm CR49 CLAMP VOLTAGE T3 FEEDBACK or VOLTAGE D Waveforms B and G superimposed Waveforms E and F superimposed J Test Points 47 46 2 ms cm 10v cm If the oscilloscope is ungrounded injury can occur if personnel touch the oscillo Scope case and other equipment simultan eously B Test Points 29 33 1ms cm 1 E Sameas B except smaller load used 2v 3a H Test Points 45 ACC 2ms cm 50v cm MUST BE 20 54 FOR LINE BALANCE WARNING Test Points 48 18 2 ms cm 0 2v cm C Test Points 37 33 ms cm lv cm F Same as C except Q7 fires later due to smaller load 2v 3a I Test Points 45 AC 2ms cm 50v cm All waveforms were taken with 115 volt 60 cps single phase input and 32vdc 10 ampere load except E and F as indicated loscope to be ungrounded Waveforms and I require the oscil If it is not desirable to unground the oscilloscope use a l kva isolation transformer between the input power source and the power supply power input i BIAS 4 REFERENCE CIRCUIT n 2 4 D es K Ww
24. RECOVERY TIME TEST SETUP 300 MSEC 2V 200 MV Eo T FULL LOAD HALF LOAD 300 MSEC HALF LOAD FULL LOAD FIGURE 5 5 TRANSIENT RECOVERY TIME WAVEFORM 5 23 ADDITIONAL SPECIFICATION CHECK 9 24 TEMPERATURE COEFFICIENT 5 25 CONSTANT VOLTAGE Proceed as follows a Connect the 3 2 ohm load resistor across the output terminals and the differential voltmeter across the S and S terminals b Turn front panel CURRENT controls fully clockwise maximum C Turn front panel VOLTAGE controls until the differential voltmeter indi cates 32 vdc d Insert the power supply into the controlled temperature oven differen tial voltmeter and load remain outside oven Set the temperature to 309C and allow half hour warm up e Record the differential voltmeter indication f Raise the temperature to 40 C and allow a half hour warm up g Differential voltmeter indication should change by less than 240 mvdc from indication recorded in step e 5 26 CONSTANT CURRENT Proceed as follows a Connect test setup shown in figure 5 3 b Tum front panel VOLTAGE controls fully clockwise maximum C Turn front panel CURRENT controls until the differential voltmeter indi cates 50 mvdc d Insert the power supply into the controlled temperature oven differen tial voltmeter and load remain outside oven Set the temperature to 30 C and allow a half hour warm up e Record the differential voltmeter indication
25. SUPPLY MANUFACTURING CODE 6A January 1966 Section I II III TABLE OF CONTENTS Title Page GENERAL INFORMATION o 1 1 Description 1 2 General 1 4 Overload Protection e o e ooo o o oo 1 7 Cooling 1 9 1 1 1 1 Monitoring 1 1 Output Terminals 3 Instrument Identification INSTALLATION 2 1 2 1 Initial Inspection 2 1 2 2 General e e e 9 n 9 9 7 1 2 1 2 4 Mechanical Check 22 1 2 6 Electrical Check 2 2 8 Installation Data e s e e o 2 1 2 9 General 22 1 2 11 Location e e 09 o o 9 o 9 c 9 9 1 2 1 2 13 Power Requirements 2 2 2 15 Power Cable 42 2 2 18 Repackaging for Shipment 2 2 OPERATING INSTRUCTIONS 3 1 Controls and Indicators 3 3 Operation 3 4 General 3 6 Normal o 3 10 Connecting Load 3 14 Remote Sensing 3 17 Remote Programming 3 26 Parallel 3 30 Series 3 35 Auto Tracking 3 38 Considerations 3 39 Pulse Loading e e o o 3 41 Output Capacitance 3 44 Negative Voltage Loading 3 46 Negative Current Loading e _ CO QO CO CO CO CO CO CO CO CO CO UNUN M CA
26. TTERN A2 A4 5 45 AS AT Al A2 AS A4 S S AS A6 A7 PROGR AMMING RESISTOR FIGURE 3 4 REMOTE RESISTANCE FIGURE 3 5 REMOTE VOLTAGE once PROGRAMMING CONSTANT VOLTAGE PROGRAMMING CONSTANT VOLTAGE U STRAPPING PATTERN STRAPPING PATTERN 2 A4 5 45 A5 AT PROGRAMMING RESISTOR FIGURE 3 6 REMOTE RESISTANCE PROGRAMMING CONSTANT CURRENT STRAPPING PATTERN 2 4 S 45 5 FIGURE 5 7 NORMAL PARALLEL STRAPPING PATTERN A2 AS A4 8 9 Q MASTER A4 S 8 AS A7 glelolelgielelelelele J uL Al A4 5 45 AS 81610181516191619161 A4 S 8 AS AS A TWO POWER SUPPLIES Al A2 A4 3 43 5 AT B THREE POWER SUPPLIES FIGURE 3 8 AUTO PARALLEL STRAPPING PATTERN 3 8 Al A2 A4 S 45 5 MASTER SLAVE Al A4 5 5 5 A TWO POWER SUPPLIES FIGURE 3 9 NORMAL SERIES STRAPPING PATTERN 2 Al A2 A4 S S AS MASTER Al A2 A3 A4 S FIGURE 3 10 AUTO SERIES STRAPPING PAT TERN B THREE POWER SUPPLIES Al 2 A4 S 5 5 AT MASTER MUST BE MOST NEG ATIVE SLAVE Al 2 A4 S S AS A TWO POWER SUPPLIES Al A2
27. amplified error voltage by increasing or decreasing the ac input current to the main power transformers as required to maintain a constant load current In constant current operation the gating circuit is biased to inhibit the input from the voltage input circuit 4 7 To prevent overvoltage and excessive surge current when the power supply is turned on the turn on circuit establishes initial conditions in the gating circuit The turn on circuit is activated by the bias and reference circuit when the power supply is turned off 4 8 voltmeter is connected across the and terminals to monitor the output voltage An ammeter is connected across current monitoring resistor R23 to monitor the output current proportional to voltage across R23 4 9 CIRCUIT DESCRIPTION See figure 4 2 at back of manual 4 10 AC INPUT 4 11 The 105 125 vac 57 63 cps single phase input is applied to transformer T2 and to the series combination of transformer T and SCR s CR17 and CR18 which are in parallel opposition The SCR s are used to regulate the dc output by control ling the average value of the ac input to transformer Tl Capacitors C11 and C12 smooth transients to prevent the SCR s from being triggered by a rapidly changing voltage from anode to cathode Resistor R21 damps oscillations that may occur due to resonance of C12 and the leakage inductance of 1 The leakage inductance of Tl limits the peak input current 4 12 DC OUTPUT 4 13 The
28. biased when the pulse occurs The other SCR is not affected by the gate pulse because it is reverse biased A gate pulse occurs each half cycle of the ac input unless the output is open The timing of the gate pulse with respect to the ac input 1s determined by the error in the dc out put via the loop action 4 40 INPUT CONTROL When an SCR is gated it conducts until its anode to cathode voltage goes to approximately zero Thus the earlier an SCR is gated on the greater the portion of the ac input that will be applied to Tl Because of the leakage inductance of T1 the conduction of an SCR may extend into the next half cycle The conduction period may be shortened at high output by the voltage across capacitor C13 through C16 being reflected back into the primary By con trolling the ac input to T1 each half cycle the average value of the voltage or current at the output of bridge rectifier CR19 through CR21 is adjusted so that dc output voltage or current is maintained constant 4 41 PROTECTION Diodes 50 and CR51 prevent anode induced reverse gate currents from being fed back to the control circuit Resistors R54 and R55 limit current in the SCR gates 4 42 BIAS AND REFERENCE CIRCUIT 4 43 GENERAL The bias and reference circuit supplies three voltages 35 6 0 and 19 5 vdc for internal power supply operation and maintains the pro gramming currents constant The 35 vdc is not regulated The 19 5 vdc 6 0 vdc a
29. cient and stability specifica tions of the power supply the external resistors shown in figures 3 10A and B should be stabie low noise low temperature less than 30 ppm per C resistors The value of these resistors is determined by multiplying the output voltage of the applicable slave by the programming coefficient 200 ohms volt 3 35 AUTO TRACKING 3 36 The strapping patterns for auto tracking operation of two and three power supplies are shown in figures 3 11A and B respectively Automatic tracking peration permits the output voltages of two or more power supplies to be referenc ed to common buss one of the power supplies master controls the magnitude of the output voltage of the others slaves for a given position of the slave output voltage controls The master must be the most negative power supply in the group The output voltage of a slave is a percentage of the master output voltage The output voltage controls of a slave determines this percentage Turn on and turn off of the power supplies is controlled by the master Remote sensing para 3 14 and programming para 3 17 can be used however the strapping patterns shown in figure 3 4 employ only local sensing and programming 3 37 The value of the external resistors shown in figure 3 11 is determined by dividing the voltage difference between the master and the applicable slave by the programming current nominally 5 ma refer to para 3 19 Finer adjustment of t
30. conductor side of board not pass through an eyelet apply heat to con ductor side of board CONDUCTOR SIDE WS 3 Bend clean tinned leads on new part and care 4 Hold part against board avoid overheating and fully inserr through eyelets or holes in board solder leads Apply heatto component leads on correct side of board as explained in step e a e a a m a a www ne ae ee DOO aes Ee In the event that either the circuit board has been damaged or the conventional method is impractical use method shown below This is especially applicable for circuit boards without eyelets 1 Clip lead as shown below 2 Bend protruding leads upward Bend lead of new component around protruding lead Apply solder using a pair of long nose pliers as a heat sink APPLY SOL DER d RRASA RERET vacas PLI 7777777 PE This procedure is used in the field only as an alternate means of repair It is not used within the factory Figure 5 7 Servicing Etched Circuit Boards 5 13 5 51 ADJUSTMENTS AND CALIBRATIONS 9 92 GENERAL 9 53 Adjustments and calibrations may be required after performance testing para 5 7 additional specification testing para 5 23 troubleshooting para 5 39 or repair and replacement para 5 50 Test points called out in t
31. conducts The firing point of Q7 is therefore determined by both the dc output error and the line voltage change Because Q7 saturates when it conducts the collector voltage approximates a rectangular wave with a negative going pulse width of approximately 20 microseconds determined by C27 and R51 The conduction of Q7 charges C25 in the positive direction clamped by CR49 When Q7 stops conducting the ramp across C25 begins again However Q7 is held cut off by the charge on C27 4 34 INITIAL CONDITIONS At the beginning of each cycle of the 120 cps pulsat ing dc certain initial conditions must be established on capacitors C25 and C27 When the negative going pulsating dc is at the end of its cycle C27 negatively charged earlier in the cycle by the feedback voltage CR44 and CR45 become forward biased and current flows from the 35 vdc bias through R52 CR46 and CR44 to dis charge C27 to approximately zero volts and through R52 CR46 and CR45 to charge C25 to approximately 0 7 volts clamped by CR49 This discharge and charge occurs rapidly so that it is completed before the next cycle begins and Q7 can con duct again Diode CR47 provides another path for the current through CR44 so that the voltage to which C27 discharges remains predictable As the negative going pulsating dc increases in the next cycle CR44 and CR45 become reverse biased 4 35 BRIDGE RECTIFIER At the zero cross over region of the voltage waveform on secondary windi
32. correct result is not obtained for a particular check do not adjust any controls proceed to troubleshooting para 5 39 5 10 RATED OUTPUT AND METER ACCURACY 5 11 CONSTANT VOLTAGE Proceed as follows Connect the 3 2 ohm load resistor across the output terminals and the differential voltmeter across the 5 and S terminals b Turn front panel CURRENT controls fully clockwise maximum C Turn front panel VOLTAGE controls until front panel voltmeter indicates 32 0 vdc d The differential voltmeter should indicate 32 0 0 64 DIFFERENTIAL VOLTMETER hp LOAD RESISTOR 2 2 CURRENT MONITORING RESISTOR REX RHEOSTAT 10 AMPERE METER SHUNT SHORTING SWITCH 4 USED ONLY FOR CONSTANT CURRENT SHORTING LOAD REGULATION SWITCH CHECK FIGURE 5 3 CONSTANT CURRENT TEST SETUP 5 2 9 12 CONSTANT CURRENT Proceed as follows a Connect test setup shown in figure 5 3 b Turn front panel VOLTAGE controls fully clockwise maximum C Turn front panel CURRENT controls until front panel ammeter indicates 10 amperes d The differential voltmeter should indicate 50 41 0 mvdc 5 13 LINE REGULATION 5 14 CONSTANT VOLTAGE Proceed as follows a Connect the 3 2 ohm load resistor across the output terminals and the differential voltmeter across the S and S terminals b Turn front panel CURRENT controls fully clockwise maximum C Connect the variable voltage transformer betwee
33. d by reading Section IV of this manual Once the principles of operation are understood logical application of this know ledge in conjunction with significant waveforms on figure 4 2 and with normal voltage information table 5 2 should suffice to isolate a fault to a part or small group of parts As additional aids the following are given a Procedure for checking the bias and reference circuit Refer to para 5 45 Trouble in this circuit could show up in many ways because it supplies internal operating voltages for the power supply and the programming currents b Procedures for checking the voltage feedback loop for the two most common troubles high or low output voltage para 5 46 or 5 47 respectively C Paragraph 5 48 which discusses common troubles 5 10 5 44 A defective part should be replaced refer to the parts list in Section VI Test points called out in the procedures are identified on the schematic diagram figure 4 2 9 45 BIAS AND REFERENCE CIRCUIT Proceed as follows a Make an ohmmeter check to be certain that neither the positive nor negative terminal is grounded b Turn front panel VOLTAGE and CURRENT controls fully clockwise maximum C Turn on power supply no load connected d Using the ac voltmeter check voltage across secondary winding 5 6 of transformer T2 If voltage indication is not 23 41 5 vrms transformer T2 may be defective e Using the differential voltmeter proceed as
34. elay T transformer motor L inductor V vacuum tube neon capacitor M meter bulb photocell etc R diode P plug X socket S device signaling lamp transistor XF fuseholder misc electronic part resistor XDS lampholder fuse RT thermistor Z network jack S switch ABBREVIATIO NS a amperes K kilg 1000 C carbon obd order by description cer ceramic peak coef coefficient pe printed circuit board com common pf picofarads 10712 farads comp composition peak to peak conn connection ppm parts per million crt cathode ray tube pos position s dep deposited paly polystyrene elect electrolytic pot potentiometer encap encapsulated prv peak reverse voltage f farads rect rectifier 7 fxd fixed rot rotary germanium rms root mean square ground ed s b slow blow h henries sect section s Hg mercury Si silicon impg impregnated sil silver ins insulation ed sl slide lin linear taper td time delay log logarithmic taper TiO titanium dioxide m milli 10 3 tog toggle M megohms tol tolerance ma milliamperes trim trimmer micro 1079 twt traveling wave tube m fr manufacturer var variable mtg mounting w with my mylar OW watts NC normally closed ww wirewound Ne neon w o without NO normally open cmo cabinet mount only nsr
35. ents are nearly constant The collector currents of Q5 and Q6 are the constant voltage and constant current programming currents respectively Resistors R39 and R41 are used for trimming Resistors R42 and R43 are collector loads Diode CR28 clamps the collector of Q5 to protect against excessive positive voltage breakdown which might occur if the voltage controls are reduced to zero rapidly positive dc output voltage would appear at collector Table 5 1 Test Equipment Required Recommended Type Characteristics Model Differential Voltmeter Sensitivity 1 mv Measure regulation HP 741A full scale min and dc voltages See note 1 Input impedance 10 calibrate meters megohms AC Voltmeter Accuracy 296 Measure ac voltages HP 403B Sensitivity 1 mv and ripple full scale min Variable Voltage Range 90 130 volts Vary and measure Transformer Equipped with voltmeter ac input voltage accurate within 1 volt Oscilloscope Sensitivity 5mv cm Measure ripple and HP 130C min transient response Differential input Battery Measure transient response Switch 10 ampere Transient response capacity Constant current load regulation 7o Resistor 3 2 ohm 5 320 w Load resistor Rex Rheostat See note 2 Resistor 5 milliohms 10am Current monitoring Any 50 mv peres 4 terminals 10 ampere meter shunt Resistor 1 000 ohms 41 2 w Measure impedance non inductive Resistor 300ohms
36. er Tracking R39 Constant Voltage Programming Current Zero Voltage Output R6 Constant Current Programming Current Zero Current Output Bias and Reference Line Regulation Line Imbalance Constant Current Load Regulation 5 25 SECTION VI REPLACEABLE PARTS 6 1 INTRODUCTION 6 2 This section contains information for ordering replacement parts 6 3 Table 6 1 lists parts in the alpha numerical order of the circuit designators and provides the following information Description See list of abbreviations below B Total quantity used in the instrument C Manufacturer s part number D Manufacturer E The Manufacturer s code number as listed in the Federal Supply Code for Manufacturers H4 1 The H P Part Number The recommended spare parts quantity for complete maintenance during one year of isolated service Column A Qm 6 4 ORDERING INFORMATION 6 5 To order replacement parts address order or inquiry either to your authorized Harrison Laboratories sales representative or to Customer Service Harrison Laboratories 100 Locust Avenue Berkeley Heights New Jersey 6 6 Specify the following information for each part Model and complete serial number of instrument B Circuit reference designator C Description 6 7 To order a part not listed in Table 6 1 give a complete description of the part and include its function and location Reference Designators 1mgooQuuu assembly K r
37. f the low output impedance of the power supply Each pair of connecting wires should be as short as possible and twisted or shielded to reduce noise pickup If shield is used connect one end to power supply ground terminal and leave the other end unconnected 3 13 If load considerations require that the output power distribution terminals be remotely located from the power supply then the power supply output terminals should be connected to the remote distribution terminals via a pair of twisted or shielded wires and each load separately connected to the remote distribution terminals For this case remote sensing should be used para 3 14 NOTE It is recommended that the voltage drop in the con necting wires not exceed 2 volts If a larger drop must be tolerated please consult a Hewlett Packard field representative 3 14 REMOTE SENSING 3 15 Remote sensing is used to ameliorate the degradation of regulation which will occur at the load when the voltage drop in the connecting wires is appreciable The use of remote distribution terminals para 3 13 is an example where remote Sensing may be required Due to the voltage drop in the load leads it may be necessary to slightly increase the current limit in constant voltage operation 3 2 CAUTION Turn off power supply before rearranging strap ping pattern at the power supply rear terminal strip If the S terminal is opened while the power supply is on the output voltage and
38. ference circuit R45 regulator line regulation am umma dumm umm Constant voltage load regulation CRI CR2 Constant voltage protection CR28 Voltage across each diode 0 6 to 0 85 vdc CR6 CRY Forward bias regulators CR10 11 CR12 CR14 CR27 CR46 9 23 Table 5 7 Checks and Adjustments after Replacement of Semiconductor Devices cont Circuit Reference Function Check Adjust CR17 18 SCR regulator Constant voltage load regulation CR19 CR20 Bridge rectifier Voltage across bridge at CR21 CR22 full output 32 vdc CR23 Output Protection Output voltage CR26 Constant current protection Constant current line and load regulation CR30 CR31 Full wave rectifier Rectifier output 67 vdc CR39 CR40 Bridge rectifier Voltage across bridge CR41 CR42 20 25 peak full wave CR43 CRS CR7 Diode switches CR8 CR44 CR45 47 CR48 CR49 CR50 CR51 VR1 Constant voltage program Full output voltage and Zero ming protection output voltage obtainable via VOLTAGE controls volt age regulation at 32 vdc output VR3 Voltage reference Bias and reference circuit line regulation VR4 Voltage reference 6 0 vdc line regulation 5 24 Table 5 8 Adjustment and Calibration Summary Paragraph Reference Adjustment or Calibration Control Device Meter Zero Meter Spring R25 Voltmeter Tracking R27 Ammet
39. ge The master will act as a constant voltage source the slave will act as a constant current source dropping its output voltage to equal the master s 3 29 AUTO PARALLEL The strapping patterns for auto parallel operation of two and three power supplies are shown in figures 3 8A and B respectively Auto parallel operation permits equal current sharing under all load conditions and allows complete control of output current from one master power supply The output current of each slave is approximately equal to the master s Because the output current controls of each slave is operative they should be set to maximum to avoid having the slave revert to constant current operation this would occur if the master output current setting exceeded the slave s 3 30 SERIES 3 31 GENERAL Two or more power supplies can be connected in series to obtain a total output voltage higher than that available from one power supply The total output voltage is the sum of the output voltages of the individual power supplies A single load can be connected across the series connected power supplies or a separate load can be connected across each power supply The power supply has a reverse polarity diode connected internally across the output terminals to protect the power supply against reverse polarity voltage if the load is short circuited or if one power supply is turned off while its series partners are on 3 32 The output current controls of each power
40. he procedures are identified on the schematic diagram figure 4 2 If an adjustment or calibration cannot be performed troubleshooting is required Table 5 8 sum marizes the adjustments and calibrations The adjustments and calibrations are performed using a 115 volt 60 cps single phase power input to the power supply 9 94 METER ZERO 5 55 Proceed as follows a Turn off power supply and allow 2 minutes for all capacitors to dis charge b voltmeter zero set screw figure 3 1 clockwise until the meter pointer is to the right of zero and moving to the left towards zero Stop when point er is on zero If the pointer overshoots zero continue rotating clockwise and re peat this step c When the pointer is exactly on Zero rotate the zero set screw counter clockwise approximately 15 degrees to free the screw from the meter suspension If pointer moves repeat steps a through c d Repeat steps a through c for the ammeter 9 56 VOLTMETER TRACKING 5 57 Proceed as follows a Connect the differential voltmeter across the 5 and S terminals b Turn front panel VOLTAGE controls until the differential voltmeter indi cates 32 vdc c Adjust R25 until the front panel voltmeter indicates 32 vdc 5 58 AMMETER TRACKING 5 59 Proceed as follows a Connect test setup shown in figure 5 3 b Turn front panel VOLTAGE controls fully clockwise maximum Turn front panel CURRENT controls until the differential vol
41. he slave output voltage can be accomplished using the slave output voltage controls In order to maintain the temperature coefficient and stability specifications of the power supply the external resistors should be stable low noise low temperature less than 30 ppm per 9C resistors 3 6 3 38 OPERATING CONSIDERATIONS 3 39 PULSE LOADING 3 40 The power supply will automatically cross over from constant voltage to constant current operation or the reverse in respone to an increase over the preset limit in the output current or voltage respectively Although the preset limit may be set higher than the average output current or voltage high peak currents or voltages as occur in pulse loading may exceed the preset limit and cause crossover to occur To avoid this unwanted crossover the preset limit must be set for the peak requirement and not the average 3 41 OUTPUT CAPACITANCE 3 42 There are capacitors internal across the output terminals of the power supply These capacitors help to supply high current pulses of short duration during constant voltage operation Any capacitance added externally will improve the pulse current capability but will decrease the safety provided by the constant current circuit A high current pulse may damage load components before the average output current is large enough to cause the constant current circuit to operate 3 43 The effects of the output capacitors during constant current operatio
42. he resistance box until the differential voltmeter indicates 50 5 0 mvdc f Choose resistor R41 shunt equal to the resistance value required in Step e 5 66 ZERO CURRENT OUTPUT 5 67 Proceed as follows a Connect test setup shown in figure 5 3 b Connect a jumper between the A1 and A3 terminals on the rear terminal strip of the power supply C Connect the resistance box in place of R20 d Adjust the resistance box until the voltage indicated by the differential voltmeter is between zero and 0 1 mvdc e Choose resistor R20 equal to the resistance value required in step d NOTE If the resistance value required is less than 7 000 ohms or greater than 17 000 ohms change R46 Replace the original R20 5 68 BIAS AND REFERENCE LINE REGULATION 5 69 Proceed as follows a Connect the variable voltage transformer between the input power source and the power supply power input Adjust the variable voltage transformer to 105 vac b Connect the differential voltmeter between the S and 5 terminals C Connect the resistance box in place of R45 d Turn front panel VOLTAGE controls until the differential voltmeter indi cates 32 vdc e Adjust the variable voltage transformer to 125 vac f Adjust the resistance box until the voltage indicated by the differential voltmeter is within 18 mvdc of 32 vdc g Choose resistor R45 equal to the resistance value required in step f NOTE If the resistance value required
43. hrough CR43 R50 R51 Poor line regulation constant voltage a Check bias and reference circuit para 5 45 b Power supply going into current limit Check constant current input circuit c Constant voltage loop oscillates Check adjustment of R17 para 5 71 Poor load regulation constant voltage a Check bias and reference circuit para 5 45 Refer to paragraph 5 69 for adjustment b Power supply going into voltage limit Check constant voltage input circuit C Constant current loop oscillates Check adjustment of 44 para 5 73 Poor line and load regulation constant current High ripple Check operating setup for ground loops b If output is floating ungrounded connect 1 capaci tor between output and ground unless particular application prohibits this C Check pi section output filter C13 C17 and Ll d Line imbalance Check adjustment of R17 para 5 70 Poor stability Check bias and reference circuit line regulation Refer constant voltage to para 5 69 Noisy programming resistors 82 88 or CR2 leaky R40 R4 or R43 noisy or drifting Q1 or Q2 defective Poor stability Check bias and reference circuit line regulation constant current Refer to para 5 69 Noisy programming resistors R9 R10 R20 R23 R38 R39 or R42 noisy or drifting Q8 defective Table 5 6 Common Troubles cont Checks a
44. indication should increase 5 0 0 5 mvdc at each step f Set the remote programming resistance to 200 ohms and repeat step e until the remote programming resistance reaches 250 ohms g Turn off power supply and reconnect normal strapping pattern figure 3 2 POWER SUPPLY UNDER TEST S 9 IK 500 MFD OSCILLATOR 300 n VOLTMETER 4038 VOLTMETER 4038 FIGURE 5 6 QUTPUT IMPEDANCE TEST SET UP 5 8 9 33 9 34 16 vdc OUTPUT IMPEDANCE Proceed as follows Connect test setup shown in figure 5 6 b Turn front panel CURRENT controls fully clockwise maximum C Turn front panel VOLTAGE controls until front panel voltmeter indicates d Adjust the oscillator for a 10 vrms Eig 0 5 cps output e Calculate and record the output impedance using the following formula Zout R 1 000 ohms Eo measured across power supply 5 and S terminals using ac voltmeter Ein measured across oscillator output terminals using the ac voltmeter f Using the formula given in step e calculate and record the output imped ance for oscillator frequencies of 100 cps 1 kc and 100 g The output impedance calculated and recorded in steps e and f should fall into the following ranges 9 35 5 36 1 dc to 0 5 cps less than 0 01 ohm 2 0 5 cps to 100 cps less than 0 5 ohm 3 100 cps to 1 kc less than 0 2 ohm 4 1 kc to 100 kc less than
45. instructed in table 5 3 5 46 HIGH OUTPUT VOLTAGE Proceed as follows a Turn front panel CURRENT controls fully clockwise maximum b Turn front panel VOLTAGE controls to mid position C Turn on power supply no load connected d Using the ac voltmeter check voltage across test points ACC and 45 If voltage indication is less than 1 0 vdc CR17 or CR18 may be shorted Using the differential voltmeter check voltage across test points 33 and 36 If voltage is not 0 8 40 12 vdc check T2 CR39 through CR43 R50 and 651 f Using the differential voltmeter proceed as instructed in table 5 4 5 47 LOW OUTPUT VOLTAGE Proceed as follows a Turn front panel CURRENT controls fully clockwise maximum b Disconnect anode or cathode of diode CR8 C Turn on power supply no load connected d Turn front panel VOLTAGE controls clockwise and observe the front panel voltmeter to see if the 32vdc output can be obtained If it can the probable cause of the low output voltage is one or more of the following 1 CR8 shorted 2 Q8 shorted 3 Q9 open 4 Q6 open 5 R40 R43 open e If the 32vdc output cannot be obtained in step d reconnect diode CR8 and turn the front panel VOLTAGE controls to mid position f Using the oscilloscope check the following 1 Waveform across test points 31 positive lead and 33 waveform on figure 4 2 If peak negative voltage is less than 15 volts Q7 R53 CR48 C25 C26 o
46. is less than 20 000 ohms troubleshooting is required Replace the original R45 9 70 LINE IMBALANCE 5 71 Proceed as follows a Connect 3 2 load resistor across the output terminals b Turn front panel CURRENT controls fully clockwise maximum c Connect the variable voltage transformer between the input power source and the power supply power input Adjust the variable voltage transformer to 125 vac d Turn front panel VOLTAGE controls until front panel ammeter indicates 10 amperes e Connect the oscilloscope across test points 18 and 48 Use internal sync f Connect the resistance box in place of R17 g Adjust the resistance box until the oscilloscope display is similar to the waveform for test points 18 48 shown on figure 4 2 Choose resistor R17 equal to the resistance value required in step f NOTE If the resistance value required is less than 5 000 ohms troubleshooting is required Replace the original R17 wenn ism em 2 2 ERAT en Lentes mM LIT TR TN a 5 72 CONSTANT CURRENT LOAD REGULATION 5 73 Proceed as follows Perform steps a through e of para 5 18 b Place a 10 megohm resistor in place R44 C Adjust the variable voltage transformer to 125 vac d Close the shorting switch e Differential voltmeter indication should change by less than 0 5 m
47. ision of Hewlett Packard Company AAADF Scans Are Reproduced With Permission Courtesy Of Agilent Technologies Inc PATENT NOTICE Patents have been applied for on circuits used in this power supply Buyer is not licensed to reproduce drawings or to utilize the circuit without written permis sion from Harrison Division of Hewlett Packard Company CLAIM FOR DAMAGE IN SHIPMENT This equipment should be tested as soon as it is received If it fails to operate prop erly or is damaged in any way a claim should be filed with the carrier A full re port of the damage should be obtained by the claim agent and this report should be forwarded to us We will then advise you of the disposition which is to be made of the equipment and arrange for repair or replacement HARRISON DIVISION OF HEWLETT PACKARD COMPANY 100 LOCUST AVENUE e BERKELEY HEIGHTS NEW JERSEY 07922 e 464 1234 AREA CODE 201 e TWX 201 464 2117
48. ly one input circuit is used at a time 4 4 The voltage and current input circuits operate in a similar manner Each circuit has a differential amplifier that amplifies an error voltage that is proportion al to the difference between the actual output and the programmed output The programmed output is determined by the resistance of the programming resistors voltage and current controls Each programming resistor has a constant current through it which is maintained by the bias and reference circuit 4 5 The voltage input circuit differential amplifier detects the error voltage that is proportional to the difference between the voltage across its programming resistors R2 R8 and the dc output voltage The error voltage is amplified and passed through the gating circuit to the SCR regulator control which triggers the SCR regulator The SCR regulator increases or decreases the ac input voltage to the main power transformer as required to maintain a constant load voltage that is equal to the programmed voltage In constant voltage operation the gating circuit is biased to inhibit the input from the current input circuit 4 6 The current input circuit differential amplifier detects the error voltage that is proportional to the difference between the voltage across its programming resistors R9 R10 and the voltage across current monitoring resistor R23 The voltage across R23 is proportional to the load current The SCR regulator responds to the
49. ming Current 5 62 Zero Voltage Output 5 64 Constant Current Programming Current M 5 9 5 5 5 5 11 A A A A d ug uda C Ci CO PD Qn XC XO 1 9 Q D CO 1 BP W CD KK M 29 12 5 14 5 14 2 14 22 14 5 14 5 19 9715 9 15 TABLE OF CONTENTS cont Section Title Page 5 66 Zero Current Output 716 5 68 Bias and Reference Line Regulation 2716 5 70 Line Inbalance oe om 5 2717 5 72 Constant Current Load Regulation s 20718 VI REPLACEABLE PARTS 6 1 Introduction 6 4 Ordering Information e MODEL 6433B REVISION Please note the following changes in the instruction manual 1 Ze 3 Wherever 6433A appears change it to 6433B Eliminate the 10A fuse and holder in the ACC side of the line Change voltage rating from 32 volts to 36 volts Change Tl from 643391 to 643391 Change C13 and C17 from 47 000 40VDC to 40 000 50VDC Mfg Part 042343 Change R21 from 160 ohm 2W to 43 ohm 2 Remove C12 from AC lead move to ACC anode of CR18 Change
50. n are as follows a The output impedance of the power supply decreases with increasing frequency b The rise time of the output voltage is increased c A large surge current causing a high power dissipation in the load occurs when the load impedance is reduced rapidly 3 44 NEGATIVE VOLTAGE LOADING 3 45 A diode is connected across the output terminals Under normal operating conditions the diode is reverse biased anode connected to negative terminal If a negative voltage is applied to the output terminals positive voltage applied to negative terminal the diode will conduct shunting current across the output ter minals and limiting the voltage to the forward voltage drop of the diode This diode protects the filter and output electrolytic capacitors i 3 46 NEGATIVE CURRENT LOADING 3 47 Certain types of loads may cause current to flow into the power supply in the direction opposite to the output current If the reverse current exceeds 0 1 ampere preloading will be necessary For example if the load delivers 1 ampere to the power supply with the power supply output voltage at 18 vdc a resistor equal to 18 ohms 18v 1a should be connected across the output terminals Thus the 18 ohm resistor shunts the reverse current across the power supply For more information on preloading refer to paragraph C4 in the H Lab Application Manual FIGURE 3 2 NORMAL STRAPPING PATTERN FIGURE 3 3 REMOTE SENSING STRAPPING PA
51. n the input power source and the power supply power input Adjust the variable voltage transformer to 105 Vac d Turn front panel VOLTAGE controls until the differential voltmeter indi cates 32 0 vdc e Adjust the variable voltage transformer to 125 vac f Differential voltmeter indication should change by less than 10 mvdc 5 15 CONSTANT CURRENT Proceed as follows Connect test setup shown in figure 5 3 b Turn front panel VOLTAGE controls fully clockwise maximum C Connect the variable voltage transformer between the input power source and the power supply power input Adjust the variable voltage transformer to 105 vac d Turn front panel CURRENT controls until front panel ammeter indicates 10 amperes e Record voltage indicated on differential voltmeter f Adjust the variable voltage transformer to 125 vac Differential voltmeter indication should change by less than 0 5 mvdc 5 3 9 16 LOAD REGULATION 5 17 CONSTANT VOLTAGE Proceed as follows a Connect the 3 2 ohm load resistor across the output terminals and the differential voltmeter across the S and S terminals b Turn front panel CURRENT controls fully clockwise maximum C Turn the front panel VOLTAGE controls until front panel ammeter indi cates 10 amperes d Record voltage indicated on differential voltmeter e Disconnect load resistor f Differential voltmeter indication should change by less than 20 mvdc 5 18 CONSTANT
52. nd Probable Causes Oscillates Check R18 C1 C4 and adjustment of R17 para 5 71 constant voltage Oscillates Check C6 C24 R22 and adjustment or R20 para 5 66 constant current and adjustment of R44 para 5 72 Output voltage does Check R6 and R47 Refer to para 5 63 not go to Zero Output current does Check R20 and R46 Refer to para 5 67 not go to Zero Table 5 7 Checks and Adjustments after Replacement of Semiconductor Devices Circuit Reference Function Check Adjust Constant voltage line and R6 R17 load regulation transient recovery time Zero voltage output Constant voltage differential amplifier Excessive transients at turn on Turn on circuit Constant voltage constant current line and load regula tion Gating Circuit R38 R39 Constant voltage program ming coefficient Constant voltage programming current regulator 40 41 Constant current program ming coefficient Constant Current programming current regulator Waveforms shown in figure R51 4 2 SCR regulator control Constant current line and R20 R44 load regulation Zero current output Constant current differential amplifier Q10 Bias and reference error Bias and reference circuit R45 detector amplifier line regulation Q11 Bias and reference series Bias and re
53. nd the programming currents are regulated 4 44 435 AND 46 0 VDC The output of secondary winding 5 6 of transformer T2 is full wave rectified by CR30 and CR31 Capacitors C20 and C21 each charge to the peak rectified voltage voltage doubling The 46 0 with respect to 5 is maintained by diodes CR6 and 14 and by zener diode VR4 The 35 includes includes the 46 0 vdc and the voltage across C21 The 46 0 vdc and the negative voltage across C20 provide the unregulated input to the 19 5 vdc regulator 4 45 19 5 VDC For the 19 5 vdc transistor Q10 is the error detector amplifier Zener diode VR3 and diode CR27 provide a reference voltage at the emitter of Q10 Voltage divider R35 R36 supplies an error voltage to the base of 4 6 Q10 which amplifies and applies it to the base of series regulator Q11 The base drive 011 adjusts the voltage across 011 as required to compensate for the error in the 19 5 vdc Resistor R37 sets the optimum current through temperature com pensated zener diode VR3 Resistor R45 improves the line regulation Resistor R56 reduces power dissipation in 011 Capacitor C22 stabilizes the loop 4 46 PROGRAMMING CURRENTS Each proaramming current is held constant in a similar manner The voltage across emitter resistors R38 and R40 is held constant by VR3 CR27 and the base emitter drop of each transistor Thus the emitter current in each transistor is constant and therefore the collector curr
54. ned by the difference between its base and emitter inputs This difference is an error voltage that is proportion al to the difference between the programmed output voltage and the actual output voltage The negative feedback from collector to base C4 and R17 R18 in parallel improves the stability of the voltage regulating feedback loop 4 2 4 18 The input from the positive side of the main rectifier C1 and R1 improves loop stability by making the differential amplifier insensitive to output voltage variations of four cps or greater Below four cps this input is negligible This input is necessary because the phase shift of the pi section output filter begins to become excessive over four cps Resistors Rl and R5 are arranged so that the four Cps input is isolated from the negative feedback input and so that necessary impedance levels are obtained looking out from the base of Ql The collector out put of Q1 is coupled to the gating circuit 4 19 CLAMPING In order to protect the differential amplifier the base of 01 is clamped with respect to S by diodes and CR2 to prevent excessive base volt age in either direction Diode CRI clamps the base to approximately 0 7 vdc CR2 and the base emitter junction of QI clamp the base to approximately 1 4 Zener diode 1 clamps the programming terminals to prevent an excessive error signal that would cause excessive output voltage This would occur for example if the programming
55. ng 3 4 of transformer T2 the voltage is insufficient to forward bias the rectifiers in the bridge In order to maintain definition between the end of one cycle of the rectified output and the beginning of the next cycle diode CR41 provides approximately 0 7 volts at the rectified output The current for CR41 is supplied through CR46 As the voltage across the secondary winding moves away from the zero cross over region CR41 becomes reverse biased 4 36 TRANSIENTS DECOUPLING AND PROTECTION Transients in the pulsating dc are reduced by R56 and C28 The base of Q7 is decoupled by C3 The voltage spike in the collector of Q7 induced by secondary winding 1 2 of transformer T3 when Q7 cuts off is clamped by CR48 The collector is decoupled by R53 and C26 4 37 SCR REGULATOR 4 38 GENERAL The SCR regulator CR17 and CR18 controls the ac input voltage and current to main power transformer in response to the voltage and current error signals In constant voltage operation the ac input voltage to T1 is adjusted so that the output voltage remains constant with changing loads In constant current operation the ac input current to T1 is adjusted so that the output current remains constant with changing loads and the output voltage is allowed to vary 4 39 GATING Each half cycle of the ac input either CR17 or CR18 is forward biased The pulse induced in secondary windings 5 6 and 7 8 of T3 by the SCR control turns on the SCR that is forward
56. onds is required for output voltage recovery to within 200millivolts of the nominal output voltage following a load change equal to one half the maximum current rating of the power supply Nominal output voltage is defined as the mean between the no load and full load voltages The transient amplitude is less than 0 5 volt per ampere for any load change between 20 and 100 of rated output current Excluding the initial spike of approximately 100 microseconds dura tion which is significant only for load rise times faster than 0 5 ampere per micro second SIZE AND WEIGHT Heiaht Width Depth Weight 3 1 2 in 19 in 17 172 33 15 FINISH Light gray front panel with dark gray case Figure 1 1 Model 6433A DC Power Supply SECTION I GENERAL INFORMATION 1 1 DESCRIPTION 1 2 GENERAL 1 3 H Lab Model 6433ADC Power Supply fig 1 1 is a completely solid State compact well regulated constant voltage constant current dc power supply suitable for either bench or relay rack operation A three wire five foot power cord is provided The output is continuously variable between 0 and 32vdc and be tween 0 and 10 amperes Detailed specifications are given in table 1 1 1 4 OVERLOAD PROTECTION 1 5 A crossover feature protects both power supply and load in constant voltage operation Automatic crossover circuitry switches the power supply from constant voltage to constant current operation if the output
57. output voltage will drop proportionately In setting the current limit allowance must be made for high peak currents which can cause unwanted cross over refer to para 3 40 3 9 CONSTANT CURRENT To select a constant current output proceed as follows a Short output terminals and adjust CURRENT controls for desired output current b Open output terminals and adjust VOLTAGE controls for maximum output voltage allowable voltage limit as determined by load conditions If a load change causes the voltage limit to be exceeded the power supply will automatical ly crossover to constant voltage output at the preset voltage limit and the output current will drop proportionately In setting the voltage limit allowance must be made for high peak voltages which can cause unwanted crossover Refer to para 3 40 3 10 CONNECTING LOAD 3 11 Two pairs of output terminals are provided on the terminal strip at the left rear side facing rear of the power supply Either pair of terminals or both may be used The terminals are marked and A separate ground terminal is located adjacent to the output terminals The positive or negative output terminal may be grounded or neither grounded floating operation permitted to 300 vdc off ground 3 12 Each load should be connected to the power supply output terminals using separate pairs of connecting wires This will minimize mutual coupling effects between loads and will retain full advantage o
58. ph 5 51 9 12 SERVICING ETCHED CIRCUIT BOARDS Excessive heat or pressure can lift the copper strip from the board Avoid damage by using a low power soldering iron 50 watts maximum and following these instructions Copper that lifts off the board should be cemented in place with a quick drying acetate base cement having good electrical insulating properties break in the copper should be repaired by soldering a short length of tinned copper wire across the break Use only high quality rosin core solder when repairing etched circuit boards NEVER USE PASTE FLUX After soldering clean off any excess flux and coat the repaired area with a high quality electrical varnish or lacquer When replacing components with multiple mounting pins such as tube sockets electrolytic capacitors and potentiometers it wil be necessary to lift each pin slightly working around the components several times until it is free WARNING 1f the specific instructions outlined in the steps below regarding etched circuit boards without eyelets are not followed extensive damage to the etched circuit board will result 1 Apply heat sparingly to lead of component to be 2 Reheat solder in vacant eyelet and quickly in replaced If lead of component passes through sert a small awl to clean inside ofhole If hole an eyelet in the circuit board apply heat on com does not have an eyelet insert awl or a 57 ponent side of board If lead of component does drill from
59. power supply should be 0 50 ma 100 ma when the programming resistance is zero ohms This tolerance can be improved by chang ing R20 For further information on improving this tolerance refer to paragraph 5 67 and to H Lab Tech Letter 1 3 25 If the resistance programming device is controlled by a switch make before break contacts should be used to avoid momentary opening of the program ming terminals To connect the remote programming resistance arrange rear termin al strapping as shown in figure 3 6 The front panel CURRENT controls are disabled when the strap between A1 and A2 is removed 3 26 PARALLEL 3 27 GENERAL Two or more power supplies can be connected in parallel to obtain a total output current greater than that available from one power supply The total output current is the sum of the output currents of the individual power supplies Each power supply can be t urned on or off separately Remote sensing para 3 14 and programming para 3 17 can be used however the strapping patterns shown in figures 3 7 and 3 8 employ only local sensing and programmi ng 3 28 NORMAL The strapping pattern for normal parallel operation of two power supplies is shown in figure 3 7 The output current controls of each power supply can be separately set The output voltage controls of one power supply master should be set to the desired output voltage the other power supply slave should be Set for a slightly larger output volta
60. r to para 4 25 The amount of current pulled from C25 by Q4 is determined by the in put from the voltage or current input circuit to the gating circuit As a result of this current flow from C25 the voltage across C25 increases negatively with re spect to the 6 0 vdc bias and has a waveshape that approximates a linear ramp Thus the slope of this ramp is determined by the voltage or current input circuit Due to the time delay in the feedback loop the slope of the ramp is constant for a half cycle of the ac input The voltage on C25 is the emitter bias forward bias when negative for Q7 and therefore helps determine the point at which Q7 conducts 4 32 AC INPUT The ac input to transformer T2 is stepped down and full wave rectified by bridge rectifier CR39 through CR43 The output of the bridge rectifier is a negative going pulsating dc 120 cps Voltage divider R50 R51 supplies a portion of this pulsating dc through C27 to the base of Q7 thus the base is reverse biased 4 33 FIRING A point is reached during each cycle of the 120 cps pulsating dc each half cycle of the 60 cps ac input when the reverse bias on the base and the forward bias capacitor C25 on the emitter of Q7 are equal and therefore Q7 has zero bias As the ramp voltage across C25 goes more negative than the base volt age the base emitter junction of Q7 begins to become forward biased When the emitter is more negative than the base by approximately 0 5 volts Q7
61. r transformer T3 may be defective 2 Ripple waveform across test points 18 positive lead and 48 wave forn shown on figure 4 2 If waveform is correct except for amplitude proceed to step 3 If waveform is incorrect proceed as follows a If the ripple waveform is half wave 60 cps instead of full wave 120 cps either SCR CR17 or CR18 may be open or the applicable gate circuit for the SCR may be defective To check the gate circuit disconnect R54 or R55 as applicable and make an ohmmeter check from the open end of the resistor to test point ACC or 45 as applicable If the resistance is greater than 55 ohms the gate circuit is defective b If the ripple waveform indicates that neither SCR has fired CR17 or CR18 may be shorted c If there is no ripple waveform both CR17 and CR18 may be open or 1 may be defective g Using the differential voltmeter proceed as instructed in table 5 5 5 48 COMMON TROUBLES Table 5 6 gives the symptoms checks and probable causes for common troubles The checks should be made using a 115 volt 60 cps single phase power input and the test equipment listed in table 5 1 9 49 REPAIR AND REPLACEMENT 9 50 Before servicing etched circuit boards refer to figure 5 7 After replacing a semiconductor device refer to table 5 7 for checks and adjustments that may be necessary If a check indicates a trouble refer to paragraph 5 39 If an adjust ment is necessary refer to paragra
62. ramming resistance Refer to para 3 17 through 3 21 b Connect the 3 Z ohm load resistor across the output terminals and the differential voltmeter across the 5 and 45 terminals C Turn front panel CURRENT controls fully clockwise maximum d Turn on power supply allow a half hour warm up and then record the differential voltmeter indication e Increase the remote programming resistance in 200 ohm steps to 3 000 ohms record the differential voltmeter indication at each step The voltage indi cation should increase 1 0 amp 0 01 vdc at each step 5 7 f Set the remote programming resistance to 5 400 ohms and repeat step e until the remote programming resistance reaches 6 4000hms g Turn off power supply and reconnect normal strapping pattern figure 3 2 9 32 CONSTANT CURRENT Proceed as follows a Turn off power supply and arrange rear terminal strapping pattern for constant current remote resistance programming as shown in figure 3 6 use the resistance box set to 75 ohms for the remote programming resistance Refer to para 3 18 and 3 23 through 3 25 b Connect test setup shown in figure 5 3 C Turn front panel VOLTAGE controls fully clockwise maximum d Turn on power supply allow a half hour warm up and then record the differential voltmeter indication e Increase the remote programming resistance in 25 ohm steps to 125 ohms record the differential voltmeter indication at each step The voltage
63. reserve the protection feature when operating the instrument from a two contact outlet use a three prong to two prong adaptor and connect the green lead on the adaptor to ground 2 18 REPACKAGING FOR SHIPMENT 2 19 To insure safe shipment of the instrument it is recommended that the pack age designed for the instrument be used The original packaging material is re If it is not available contact your Hewlett Packard field office for packing usable packing carton part number is included in the parts materials and information list 2 20 Attacha tag to the instrument which specifies the owner model number full serial number and service required or a brief description of the trouble 2 2 9 5 PILOT VOLTMETER ZERO SET AMMETER LIGHT DS1 F USE 4 DC Power SUPPLY 2 06 0175 O M0 VOLTAGE CURRENT 2 COARSE a A ue FINE HAEEISON LABORATORIES BERKELEY HEIGHTS OFF ON COARSE FINE COARSE FINE SWITCH VOLTAGE VOLTAGE CURRENT CURRENT i R2 R8 R10 R9 O TURN ON POWER SUPPLY ADJUST OUTPUT VOLTAGE OBSERVE VOLTMETER SHORT OUTPUT TERMINALS AT REAR OF POWER SUPPLY AND ADJUST OUTPUT CURRENT LIMIT OBSERVE AMMETER 6 REMOVE SHORT AND CONNECT LOAD TO OUTPUT TERMINALS 9 Figure 3 1 Controls and Indicators SECTION III OPERATING INSTRUCTIONS 3 1 CONTROLS AND INDICATORS 3 2 The controls and indicators are illustrated in figure 3 1 3 3
64. supply are operative and the cur rent limit is equal to the lowest control setting If any output current controls are set too low with respect to the total output voltage the series power supplies will automatically crossover to constant current operation and the output voltage will drop Remote sensing para 3 14 and programming para 3 17 can be used however the strapping patterns shown in figures 3 9 and 3 10 employ only local sensing and programming 3 33 NORMAL The strapping pattern for normal series operation of two power supplies is shown in figure 3 9 The output voltage controls of each power supply must be adjusted to obtain the total output voltage 3 34 AUTO SERIES The strapping patterns for auto series operation of two and three power supplies are shown in figures 3 10A and B respectively Auto series operation permits control of the output voltage of several power supplies slaves from one master power supply The master must be the most negative power supply of the series To obtain positive and negative voltages the terminal of the mas ter may be grounded For a given position of the slave output voltage controls the total output voltage is determined by the master output voltage controls The output voltage controls of a slave determines the percentage of the total output voltage that the slave will contribute Turn on and turn off of the series is controlled by the master In order to maintain the temperature coeffi
65. t made across the load includes the effect of the impedance of the leads connecting the load these leads can have an impedance several orders of magnitude greater than the output impedance of the power supply When measuring the output voltage of the power supply use the S and S terminals 5 5 output current measurements the current monitoring resistor should be a four terminal resistor The four terminals are connected as shown in figure 5 2 CURRENT MONITORING TERMINALS EXTERNAL LOAD TO GROUNDED TO UNGROUNDED TERMINAL OF TERMINAL OF POWER SUPPLY POWER SUPPLY MONITORING RESISTOR OAD L TERMINALS Figure 5 2 Output Current Measurement Technique 5 6 When using an oscilloscope ground one terminal of the power supply and ground the case at the same ground point Make certain that the case is not also grounded by some other means power line Connect both oscilloscope input leads to the power supply ground terminal and check that the oscilloscope is not exhibit ing a ripple or transient due to ground loops pick up or other means 2 7 PERFORMANCE CHECK 9 8 GENERAL 5 9 performance check is made using 115 volt 60 cps single phase in put power source The performance check is normally made at a constant ambient room temperature The temperature range specification can be verified by doing the performance check at a controlled temperature of 09C and at a controlled tempera ture of 50 C If the
66. ter HP 741A was used for all measurements Table 5 3 Bias and Reference Circuit Troubleshooting Meter Meter Normal If Indication is not Normal Step Common Positive Indication Check the Following Parts 33 421 7 vdc CR31 C21 CR6 CR14 VR4 6 2 40 3 34 1 41 7 CR30 C20 19 5 41 0 Q10 011 CR27 VR3 10 3 40 6 vdc 9 7 40 5 vdc R40 R43 9 7 40 5 R38 R42 Q5 Table 5 4 High Output Voltage Troubleshooting Meter Meter Common Positive Response Probable Cause Emitter of Q4 29 4 shorted b R16 shorted C RI5 shorted 17 0 85 vdc CR7 open 33 2 vdc Ql open Q2 shorted shorted R2 R8 open Table 5 5 Low Output Voltage Troubleshooting Meter Meter Common Positive Response Probable Cause Emitter of O4 a Q4 open b R16 open C R15 open shorted a 1 shorted b Q2 open C R2 R8 shorted 5 20 Table 5 6 Common Troubles Symptom Checks and Probable Causes Power supply has internal short Disconnect Collector of Q7 turn on power supply and check voltages refer to table 5 2 or figure 4 2 If fuse blows with Q7 disconnect ed check CR17 CR18 and T3 Fuse blows when power supply is turned on a Check bias and reference circuit para 5 45 Refer to paragraph 5 69 for adjustment b Check line input to SCR regulator control circuit T2 CR39 t
67. terminals were opened accidentally To prevent overshoot when the power supply switches from constant current to constant voltage diodes CR9 and CRIO clamp the collector of Q1 Resistor R30 provides a small bleed current for CRIO 4 20 CURRENT INPUT 4 21 GENERAL The current input circuit is basically a differential amplifier Q8 Q9 that detects any current difference between the programmed output current proportional to voltage across current controls and the actual output current pro portional to voltage across current monitoring resistor R23 The differential amplifier output voltage varies in proportion to the output current variation 4 22 Q8 Q9 INPUT The input to the differential amplifier across bases of Q8 Q9 is the voltage difference across current controls R9 R10 and current monitoring resistor R23 Because the programming current is constant in constant current operation the voltage input to the differential amplifier varies as the load current through R23 error voltage Capacitors C6 and C24 and resistor R22 provide gain roll off at high frequencies Diode CR26 clamps the voltage 0 7 vdc across the emitter base junction of Q9 and R20 This clamping action prevents excessive reverse base voltage in Q9 when very large load current is drawn output terminals shorted To prevent overshoot when the power supply switches from constant voltage to constant current operation diodes CR10 and CR12 clamp the collector of 08
68. tmeter indi cates 50 mvdc Adjust R27 until the front panel ammeter indicates 10 amperes 5 60 CONSTANT VOLTAGE PROGRAMMING CURRENT 5 61 Proceed as follows a Connect a 6 400 ohm 0 1 1 2 w resistor between terminals S and A6 on the rear terminal strip of the power supply b Disconnect the jumper between terminals A6 and A7 C Connect the resistance box in place of R39 shunt d Connect the differential voltmeter between the 45 and 5 terminals e Adjust the resistance box until the differential voltmeter indicates 32 40 16 vdc f Choose resistor R39 shunt equal to the resistance required in step 5 62 ZERO VOLTAGE OUTPUT 5 63 Proceed as follows a Connect a jumper between the 45 and A7 terminals on the rear terminal strip of the power supply b Connect the differential voltmeter between the S and S terminals C Connect the resistance box in place of R6 d Adjust the resistance box so that the voltage indicated by the differen tial voltmeter is between zero and 10 mvdc e Choose resistor R6 equal to the resistance value required in step d 5 64 CONSTANT CURRENT PROGRAMMING CURRENT 5 65 Proceed as follows a Connect test setup shown in figure 5 3 b Connect 250 ohm 0 1 1 2w resistor between terminals A2 and on the rear terminal strip of the power supply c Disconnect the jumper between terminals A1 and A2 d Connect the resistance box in place of RAJ shunt e Adjust t
69. ul taneously with remote programming However the strapping patterns shown in figures 3 4 3 5 and 3 6 employ only local sensing and do not show the load connections CAUTION Turn off power supply before rearranging strap ping pattern at the power supply rear terminal strip If the current programming terminals are opened while the power supply is on the out put current will exceed its maximum rating and may result in damage to the load The power supply will not be damaged The constant volt age programming terminals have a zener diode connected internally across them to limit the programming voltage and thus prevent excessive output voltage 3 19 CONSTANT VOLTAGE In the constant voltage mode of operation either a resistance or voltage source can be used for remote programming For resistance programming the programming coefficient fixed by the programming current is 200 ohms per volt output voltage increases 1 volt for each 200 ohms in series with programming terminals The programming current is adjusted to within 196 of 5 ma at the factory If greater programming accuracy is required change R39 shunt The programming resistance should be a stable low noise low temperature less than 30 ppm per 9C resistor with a power rating at least 10 times its actual dissi pation 3 20 The output voltage of the power supply should be 0 420 mv 100 mv when the programming resistance is zero ohms This tolerance can be improved b
70. und ed to avoid ground loops and circulating currents NOTE 2 To obtain 3 20hms connect rheostat across output terminals turn front panel CURRENT con trols fully clockwise maximum adjust front panel VOLTAGE controls for 32 vdc and adjust rheostat until output current is 10 amperes REFERENCE VOLTAGE SOURCE LOAD NULL DETECTOR FIGURE 5 1 DIFFERENTIAL VOLTMETER SUBSTITUTE TEST SETUP SECTION V MAINTENANCE 5 1 GENERAL 5 2 Table 5 1 lists the type of test equipment its required characteristics its use and a recommended model for performing the instructions given in this section Upon receipt of the power supply the performance check 5 7 should be made This check is suitable for incoming inspection Additional specification checks are given in paragraphs 5 24 through 5 36 If a fault is detected in the power supply while making the performance check or during normal operation pro ceed to the troubleshooting procedures para 5 39 After troubleshooting and re pair 5 50 perform any necessary adjustments and calibrations para 5 5 Before returning the power supply to normal operation repeat the performance check to ensure that the fault has been properly corrected and that no other faults exist Before doing any maintenance checks turn on power supply allow a half hour warm up and read the measurement techniques para 5 3 9 3 MEASUREMENT TECHNIQUES 5 4 measuremen
71. vdc If voltage change is greater than 0 5 mvdc reduce the 10 megohm resistor to 9 megohms set the variable voltage transformer to 105 vac open the shorting switch record the differential voltmeter indication and repeat steps c and d Repeat this process reducing the 10 megohm resistor 1 megohm steps until the voltmeter change is less than 0 5 mvdc Changes smaller than 1 megohm may be required to obtain the optimum resistance value for R44 Choose resistor R44 equal to the optimum resistance value required NOTE If the resistance value required is less than megohm troubleshooting is required Re place the original R44 Table 5 2 Normal Voltage Typical From to Voltage Peak to Peak Values 19 5 441 0 vdc 34 1 1 7 vdc 6 0 0 3 vdc 33 0 41 7 10 3 40 6 vdc 9 7 40 5 vdc 9 7 40 5 vdc 7 1 40 7 3 1 40 3 vdc 0 81 40 1 6 6 42 0 vdc 3 7 0 6 0 59 40 1 10 0 40 5 33 5 0 5vdc 0 72 0 1 0 04 0 1 0 45 40 07 vdc 0 06 20 1 0 82 40 1 1 14 40 2 vdc 1 0 40 5 7 0 41 1 0 8 40 1 vdc 46 0 42 3 66 0 45 3 vpp 14 0 41 4 These measurements were made with 115 volt 60 cps single phase power input the front panel CURRENT controls fully clockwise maximum the front panel VOLTAGE controls set for 32 vdc out put and 3 2 ohm load resistor across the out put terminals 10amperes Differential voltme
72. y chang ing R6 For further information on improving this tolerance refer to paragraph 5 63 and to H Lab Tech Letter 1 3 21 Ifthe resistance programming device is controlled by a switch make before break contacts should be used in order to avoid momentary opening of the program ming terminals To connect the remote programming resistance arrange rear terminal strapping pattern as shown in figure 3 4 The front panel VOLTAGE controls are disabled when the strap between A6 and A7 is removed 3 22 If a voltage source is used as the remote programming device the output voltage of the power supply will vary in a 1 to 1 ratio with the programming voltage The load on the voltage source will not exceed 25 microamperes To connect the programming voltage arrange rear terminal strapping pattern as shown in figure 3 5 3 23 CONSTANT CURRENT In constant current operation resistance program ming is used The resistance programming coefficient fixed by the programming current is 25ohms per ampere output current increases 1 ampere for each 25 ohms in series with programming terminals The programming current is adjusted to within approximately 1096 of 4 ma at the factory If greater programming accuracy is required change R41 shunt The programming resistance should be a stable low noise low temperature less than 30 ppm per 9C resistor with a power rating at least 10 times its actual dissipation 3 4 3 24 The output current of the

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