TeraOhm 5kV
Contents
1. 11 5 Measurements mmmmmemmm nun mmnn nm nn nn nn nn nn nn nn nn nn nenn nun 12 5 1 Generally about DC High voltage testing 12 52 Guard iermnalre re 15 5 3 FINSr Oplion se m 16 5 4 Voltage measurement 18 5 5 Insulation Resistance measurement 18 5 6 Diagnostic teSt 20 5 7 Step Voltage Insulation Resistance testing 24 5 8 Withstanding voltage 26 6 Operation with Results nun nnna 29 6 1 Store Recall and Clear Operation 29 6 2 Data transferrem e ace ae ears aes eeaeee e ea 31 7 Maintenance mm mm mm nn nn nn nn nn nn nn nn nenn 32 7 1 Inspections eerta aea es een 32 7 2 Battery Replacement 32 7 3 Gleaning ss cine ana cn eee cm er Cae a a ae ane 33 7 4 GAIT ALIO M82 e aoe apse eae oe ape ace Saag gaa eee 33 oa OGNIE ee a ee a a ee 33 8 Specifications nme nn nn nn nn nn nennen nn 34 8 1 Measurements2. 34 8 2 General specifications 36 TeraOhm 5kV 1 General introduction 1 1 Features The TeraOhm 5kV Tester is a portable battery mains powered test instrument intended for testing of Insulation Resistance by using high test voltages of up to 5 kV It operates on a SIMPLE and CLEAR basis The instrument is designed and produced with the extensive knowledge and experience acquired through many years of dealing with similar test equipment Available functions offered by the TeraOhm 5kV Tester e High Insulation Resistance measurement up to 5 TQ Programmable test voltage 250 V up to 5 kV Programmable timer 1s up to 30 min Automatic discharge of tested object after measurement completion Capacitance measurement e Insulation Resistance measurement versus test voltage step up voltage Five discrete test voltages proportionately set within preset test voltage range Programmable timer 1min up to 30 min per step e Polarization Index Pl Dielectric Absorption ratio and Dielectric Discharge ratio Pl RINs t2 R ns t1 DAR RO1min R15s DD Idis 1min C U e Withstanding voltage DC up to 5 5 kV Programmable ramp test voltage 250 V up to 5 kV High resolution ramp approx 20 V per step Programmable threshold current e Voltage and frequency measurement up to 600 V AC DC A dot matrix LCD offers easy to read results and
3. 13 TeraOhm 5kV Time dependence test Diagnostic test POLARISATION INDEX The purpose of this diagnostic test is to evaluate the influence of the polarization part of insulation Rpi Cpi After applying a high voltage to an insulator the electric dipoles distributed in the insulator align themselves with the applied electrical field This phenomena is called polarization As the molecules polarize a polarization absorption current that lowers the overall insulation resistance occurs The absorption current Ip typically collapses after a few minutes If the overall resistance doesn t increase this means that other currents e g surface leakages dominate the overall insulation resistance PI is defined as the ratio of the measured resistances in two time slots The most typical ratio is 10 min value to 1 min value but not as a rule The test is typically performed at the same voltage as the insulation resistance test If the one minute insulation resistance is greater than 5000 MQ then this measurement may not be valid new modern types of insulation Oiled paper used in transformers or motors is a typical insulation material that requires this test In general insulators that are in good condition will show a high polarization index while insulators that are damaged will not Note that this rule is not always valid Refer to Metrel s handbook Insulation Testing Techniques for more information Genera
4. TeraOhm 5kV MI 2077 User Manual Version 1 5 Code No 20 750 378 lt 4 METREL Distributor Producer METREL d d Ljubljanska 77 SI 1354 Horjul Tel 386 1 75 58 200 Fax 386 1 75 49 226 E mail metrel metre si http www metrel si Mark on your equipment certifies that this equipment meets the requirements of the EU European Union concerning safety and interference causing equipment regulations 2002 Metrel No part of this publication may be reproduced or utilized in any form or by any means without permission in writing from METREL TeraOhm 5kV Table of contents 1 General introduction ummmummmmmemen nme nn nenn nnn 4 el Fels ne erg 4 1 2 Applied Standards 4 2 Instrument Description umummmemmnemmn nm nm nnananenunenn 5 2 1 Instrument Casing 5 2 2 Operator s Panel 5 2 S CONMECIONS ite sas eee ae ee ae ea i A eee 6 2 4 Bottom Section Hr nn 7 2 5 ROCESS ONIGS ri ee bans Heise as beens doe cineee aedpe cae ene eaee 7 3 WalinS 2 222 2n nn nn 8 4 Performing measurements nun 10 4 1 Switching on the instrument 4444444 mm 10 4 2 Configuration
5. 4 First introduction Fig 5 Auto calibration state Note If the instrument detects incorrect state during the autocalibration the following warning message will be displayed ERROR TEST LEADS CONNECTED DISCONNECT AND SWITCH ON THE INSTRUMENT AGAIN CONDITIONS OUT OF RANGE PRESS START TO CONTINUE Possible reasons for out of range conditions are excessive humidity too high temperature etc In this case it is possible to perform measurements but results could be out of technical specification Backlight operation After turning the power on the LCD backlight is automatically turned on It can be turned OFF and ON by simply clicking the LIGHT key Backlight turns off automatically approximately 10s after switching it ON if the instrument is supplied by the internal battery 10 TeraOhm 5kV Off function The instrument can be switched OFF only by pressing the ON OFF key The auto off function is not available due to the possible long term measurements 4 2 Configuration The configuration function enables the selection and adjustment of the parameters that are not directly involved in the measurement procedure Figure 6 In the lower section of the display the supply status date and time is shown same in all functions The following procedure must be carried out when adjusting some of the configuration parameters 1 Use and J arrows to select parameter line to be adjusted 2 Use lt and arrows to c
6. Output power 5 W max Display range Test voltage V Resolution Accuracy 0 5000 1V 3 of reading 3 V Current Display range mA Resolution Accuracy 1 1 4mA 10 pA 100 999 uA 1 yA 10 99 9 pA 100 nA 1 9 99 pA 10 nA 5 of reading 0 05 nA 100 999 nA 1nA 10 99 9 nA 0 1 nA 0 9 99 nA 0 01 nA Noise current rejection resistive load Filter option Maximum current 50Hz mA r m s OFF 1 5 Fili 2 5 Fil2 4 5 Fil3 5 34 TeraOhm 5kV Generator Capability vs Resistance Output 6 voltage kv gt 4 3 2 4 0 0 1 1 10 100 Resistance under test M2 Note examples of selected output voltage Withstanding voltage Voltage DC Display range Withstanding voltage V Resolution Accuracy 0 5500 1V 3 of reading 40 V Leakage current Display range Itrigg mA Resolution Accuracy 0 1 4 1 uA 3 of reading 3 digits Voltage Voltage AC or DC Display range External Voltage V Resolution Accuracy 0 600 1V 3 of reading 3 V Frequency of external voltage Display range Hz Resolution Accuracy 0 and 45 65 0 1 Hz 0 2 Hz Note for frequency between 0 and 45 Hz displayed lt 45 Hz for frequency over 65 Hz displayed gt 65 Hz Input resistance 3 MQ 10 35 TeraOhm 5kV Capacitance Measuring range C 50 uF Display range C Resolution Accuracy 0 99 9 nF 0 1 nF
7. line Fill with increased integrating time 4 s Fil2 with additional cyclic averaging of 5 results Table 2 Filter options THE PURPOSE OF FILTERING In simple terms the filters smooth the measured currents by means of averaging and bandwidth reduction There are various sources of disturbance AC currents at the mains frequency and its harmonics switching transients etc cause the results to become unstable These currents are mostly crosstalk through insulation capacitances close to live systems Other currents induced or coupled in the electromagnetic environment of the insulation under test Ripple current from internal high voltage regulator Charging effects of high capacitive loads and or long cables Voltage changes are relatively narrow on high resistance insulation so the most important point is filtering of the measured current Note Any of the selected filter options increases the settling time with Fil1 to 60 s Fil2 to 70 s and Fil3 to 120 s It is necessary to pay close attention to the selection of time intervals when using filters The recommended minimum measuring times when using filters are the settling times of the selected filter option Example 1 A noise current of 1 mA 50 Hz adds approximately 15 distribution to the measured result when measuring 1 GQ By selecting FIL1 option the distribution will reduce to less than 2 In general using FIL2 and FIL3 will further impr
8. see the right part of the figure 14 can optionally be saved by pressing the MEM key twice see the chapter 6 1 Store Recall and Clear Operation U U 0 8U 0 6U 0 4U 0 2U 0 T 2T 3T 47 ST t Fig 15 Step up test voltage 24 TeraOhm 5kV Legend of displayed symbols STEP VOLTAGE Name of selected function Off Fill Fil2 Fil3 Filter type enabled see the chapter 5 3 Configuration 1500V Set test voltage step 250 V U 1593V Actual test voltage measured value I 0 00nA Actual test current measured value C 0 6nF Capacitance of measured object Actual test duration 00V gt 300GQ Last result of 1 step 00V gt 600GQ Last result of 2 step 00V gt 900GQ Last result of 3 step 1200V gt 1 2TGQ Last result of 4 step 1500V gt 1 5TO Last result of 5 step 1 343V 1 step voltage 2 step voltage U4 1284V 4 step voltage 5 step voltage Notes Timer information is displayed from the start of the measurement until the completion of each step measurement Timer information shows the complete measurement period after the completion of the measurement A high voltage warning symbol appears on the display during the measurement to warn the operator of a possible dangerous test voltage The value of capacitance is measured during the final discharge of measured object Set up parameters for Step Voltage test Press the SELECT key Set up menu appears on sihbi men display
9. 100 999 nF 1 nF 5 of reading 2 digits 1 50 pF 10 nF Full scale value of capacitance is defined according to the following equation Crs 10uF Utes kV Dielectric absorption ratio DAR Display range DAR Resolution Accuracy 0 99 9 0 01 5 of reading 2digits Polarization index PI Display range PI Resolution Accuracy 0 99 9 0 01 5 of reading 2 digits Dielectric discharge test DD Display range DD Resolution Accuracy 0 99 9 0 01 5 of reading 2 digits Capacitance range for DD test 5 nF to 50 uF 8 2 General specifications Battery power supply eeeeeeeeeeeteeeeeeeees Mains power supply uuueeeesssessnnnnnnnnnnnnnnnnn Optional on request uunsmnnnnennnnnnnnnn Protection classification gt Over voltage category uuceeeennnseennnnnnnnennn Pollution degree nasse Degree of protection en Dimensions Ww x hx A eeeeeseeeennnnnnnneennennnen Weight without accessories with batteries Visual and sound warningS seeeee DISDIAY san oia re a a aee Working temperature range ccccee Nominal reference temperature range Storage temperature range cccceeeeeees Maximum humidity ccceececeeeeeeeeeeeeees Nominal reference humidity range AUTOCALIBRATION Auto calibration of
10. be calculated from Tramp Tstep Ustop Ustart 20 V If Tstep is set to 00min 00s then the ramp voltage increases by approximately 20 V per 2s Warning e Refer to Warnings chapter for safety precautions 28 TeraOhm 5kV 6 Operation with Results 6 1 Store Recall and Clear Operation The instrument contains battery backup storage to retain the stored results This is to enables the user first to make the measurements and later to recall them analyze and print results or transfer them to a computer for further analysis INSULATION RESISTANCE Off After pressing the MEM key menu according 1 2 9 en Gk i is di 1 82 3nA to the figure 20 is displayed Save clear and tatdlnin 24e a recall operations are offered 10M 1008 16 106 1006 iT Rmax 12 969 SAVE CLR RCL nnnn Rmin 12 300 TES CLR RCL oooi The nnnn means ser number of stored 17 Jan 2000 Or 24 result Fig 20 Storage operation menu There are the following possibilities selectable with lt or gt arrow keys To store result Select SAVE and confirm store operation by pressing the MEM key To recall stored result Select RCL and confirm recall operation by pressing the MEM key the last stored result will be displayed The upper menu is replaced with Recall 0006 Figure 0006 presents the ser No of the stored result By using the T and J keys also the other stored results can be recalled Press the ESC or Start k
11. measuring system 7 2 V 9 V DC 6 x 1 2V NiCd or NiMH IEC LR14 230V AC 6 10 45 Hz 65 Hz 25 VA 115V AC 6 10 45 Hz 65 Hz 25 VA double insulation E CAT III 600 V 2 IP 44 26 5 x 11 x 18 5 cm 2 1 kg yes LCD dot matrix with backlight 160 x Non volatile internal memory 1000 measurements with time and date 10 50 C 10 30 C 20 70 C 95 RH 0 40 C non condensing 40 60 RH every time after turning power on TeraOhm 5kV CONNECTING SYSTEM Three safety banana sockets OUT OUT and GUARD Guard resistance u 300 kQ DISCHARGING Every time after measurement completion Discharging resistance 100 KQ 10 SERIAL COMMUNICATION RS232 serial communication galvanic separated Baud rates ee 2400 4800 9600 19200 baud 1 stop bit no parity EEIE LEO EREET standard RS232 9 pin D female CLOCK Built in Real time clock nn Displayed permanently and stored as a parameter in combination with the result 37
12. recall and erase results See SELECT key to enter set up mode for the selected function or to select the active parameter to be set rennen cursor key to select an option upward Den w cursor key to select an option downward TION 4 cursor key to decrease the selected parameter Booi gt cursor key to increase the selected parameter gt ARE ESC key to exit the selected mode TOs Light key to turn the display backlight ON or OFF TeraOhm 5kV 2 3 Connectors The TeraOhm 5 kV Tester contains the following connections Connection of test leads to three banana safety sockets 1 2 3 Connection of the communication cable to the 9 pin RS 232 connector 4 and Mains supply cable connection to the mains socket 5 e Use original test accessories only Max allowed external voltage between test terminals and ground is 600 V Max allowed external voltage between test terminals is 600 V Fig 2 Connectors Legend Mies Positive Insulation Resistance test terminal Bude Negative Insulation Resistance test terminal REN GUARD test terminal intended to lead away potential leakage current while measuring the Insulation Resistance te va Galvanic separated RS 232 connector to connect the instrument to PC Dixie Mains connector to connect the instrument to the mains supply TeraOhm 5kV 2 4 Bottom Section The bottom assembly is presented in the figure below The carrying strap is fixed to the bottom
13. DIAG Starting time and Unominal nominal test voltage Analyzing trend of measured insulation resistance and calculation of DAR and PI are very useful maintenance tests of insulating material DIELECTRIC DISCHARGE TESTING DD DD is the diagnostic insulation test carried out after the completion of the Insulation Resistance measurement Typically the insulation material is left connected to the test voltage for 10 30 min and then discharged before DD test is carried out After 1 minute a discharge current is measured to detect charge re absorption of the insulation material A high re absorption current indicates contaminated insulation mostly based on moisture _ Idis min mA DD ulvjelr where Idis 1min discharging current measured 1 min after regular discharge MP test voltage NG isa ieca alain capacitance of tested object Measurement procedure Connect the test leads to the instrument and to the measured object Press the START key to start the measurement Wait until set timer runs out result is displayed Wait until the object under test has discharged The result see the right part of the figure 11 can optionally be saved by pressing the MEM key twice see the chapter 6 1 Store Recall and Clear Operation Legend of displayed symbols DIAGNOSTIC TEST Name of selected function Off Fill Fil2 Fil3 Filter type enabled see the chapter 5 3 Configuration Capacitance of measu
14. N RESISTANCE Off INSULATION RESISTANCE Off 5 8 1 1000Y U 1664 GR 183nA tm Gimin 19s C 0 nF 100K 1h 10M 1008 16 106 1006 AT 10h 100M 1G 10G 1006 iT Rmax __ Rmax 5 816 Rmin ___ Rmin 5 7760 Initial display Display with results Fig 9 Insulation Resistance function display states 18 TeraOhm 5kV Measurement procedure Connect the test leads to the instrument and to the tested object Select INSULATION RESISTANCE function using the rotary switch knob Press the START key and release it continuous measurement starts to run Wait until the test result has stabilized then press the START key again to stop the measurement or until set timer runs out if enabled Wait for the object under test to be discharged The result see the right figure above can optionally be saved pressing the MEM key twice see the chapter 6 1 Store Recall and Clear Operation Legend of displayed symbols INSULATION RESISTANCE Name of selected function OPT Pili Pil2 PILS Filter type enabled see the chapter 5 3 Configuration Capacitance of measured object Timer information test duration Bar Analog presentation of result Maximum value of result only if timer is enabled Minimum value of result only if timer is enabled Notes Ifthe timer is disabled then OFF is displayed instead of the timer value During the measurement the timer information displays the time needed for the completi
15. able Ustart Initial test voltage Tstep Test voltage duration per one step Tend Constant test voltage duration after reaching End value PRESSEN Time u 5 Perera Breakdown voltage Selecting this function displays the following states initial state and state with results after completion of the measurement 26 TeraOhm 5kV WITHSTANDING VOLTAGE DC 2100 2200 tr 68min 16s I 1 318mA WITHSTANDING VOLTAGE DC Voltage break Pa 14 Jan 2006 12 46 Initial display Display with results Fig 18 Withstanding Voltage function display states Measuring procedure Connect the test leads to the instrument and to the measured object Press the START key to start the measurement Wait until the set timers run out or until breakdown occurs the result is displayed Wait until the object under test is discharged The result see the right part of the figure 18 can optionally be saved by pressing the MEM key twice see the chapter 6 1 Store Recall and Clear Operation Note Breakdown is detected when the measured current reaches or exceeds the set current level It rig Legend of displayed symbols WITHSTANDING VOLTAGE DC Name of selected function Start test voltage 2000V Stop test voltage 2053V Actual test voltage measured value Actual test current measured value tm 01min 00s Notes Timer information shows the time needed to accomplish each step during the measurement and it s
16. afety precautions 5 6 Diagnostic test Selecting this function displays the following states initial state and state with results after the completion of the measurement DIAGNOSTIC TEST 1 9 7 456 U 477U I G 24 inf tm 38min Ads C 1 62uF 100K 1H 10M 1004 R imin ___ Ri min ___ R36min ____ 00K iM 10K 100M dG 106 1006 1 RG imin 12 9G2 PIi 1 43 RiG min 19 2G2 PI2 1 82 R36min 19 TGR DD 6 61 Initial display Display with results Fig 11 Diagnostic test display states This is a long duration test for evaluating the quality of the insulation material under test The results of this test enable a decision to be made on the preventive replacement of the insulation material DIELECTRIC ABSORPTION RATIO DAR DAR is ratio of Insulation Resistance values measured after 15s and after 1minute The DC test voltage is present during the whole period of the measurement also Insulation Resistance measurement is running At the end DAR ratio is displayed DAR Ramin R 1 5s 20 TeraOhm 5kV Some applicable values DAR value Tested material status lt 1 25 Not acceptable Considered as good insulation Excellent Note When determining Riso 15s pay attention to the capacitance of tested object It has to be charged up in the first time section 15s Approximate maximum capacitance using 3 S C url t bHO 3 U WV where aa period of first time unit e g 15s A attests test vol
17. all associated parameters Operation is simple and clear the operator does not need any special training except reading and understanding this Users Manual to operate the instrument The instrument allows storage of test results Professional PC SW enables simple transfer of test results and other parameters in both directions between the test instrument and PC 1 2 Applied Standards Instrument operation IEC EN 61557 2 Electromagnetic compatibility EMC EN 61326 Class B Safety EN 61010 1 instrument EN 61010 031 accessories TeraOhm 5kV 2 Instrument Description 2 1 Instrument Casing The instrument is housed in a plastic casing that maintains the protection class defined in the general specifications The casing is equipped with a carrying strap which is intended for the instrument to be used hung around the operator s neck Short technical specification is available on base of the housing 2 2 Operator s Panel The operator s panel consists of a dot matrix LCD a rotary switch and a keypad see the figure below DIAGNOSTIC STEP VOLTAGE INSULATION MTHSTANDIN ee eee teiiGmin BOs RESISTANG VOLTAGE inok iH 40H 00H di dG ifs if CONFIG TeraOhm 5kV d Rotary switch Belt slots Fig 1 Front panel Legend ER START key to start any measurement PEO ON OFF key to switch the instrument ON or OFF EE MEM key to store
18. e program Teralink exe The PC and the instrument automatically recognize each other The program on the PC enables the following possibilities download data clear storage change and download user data prepare a simple report form prepare a file to import to a spreadsheet The program Teralink exe is a Windows 2000 XP based PC software Read file README TXT for instructions on installing and running the program 31 TeraOhm 5kV 7 Maintenance 7 1 Inspection To maintain the operators safety and to ensure the reliability of the instrument it is advisable to inspect the instrument on a regular basis Check that the instrument and its accessories are not damaged If any defect is found please consult your service center distributor or manufacturer 7 2 Battery Replacement The instrument is designed to be powered by rechargeable battery supported with mains supply The LCD contains an indication of low battery condition When the low battery indication appears the battery has to be replaced or recharged connect the instrument to the mains power supply for 14 hours to recharge cells battery 2200 mAh Typical charging currents is 150 mA Note e Operator does not need to disconnect the instrument from mains supply after the full recharging period The instrument can be connected permanently Battery cells are stored in the bottom section of the instrument casing under the battery cover In case of de
19. ect whilst testing it risk of electric shock TeraOhm 5kV e Incase of a capacitive test object long tested cable etc automatic discharge of the object may not be done immediately after finishing the measurement Please wait discharging message will be displayed HANDLING WITH CAPACITIVE LOADS Note that 40 nF charged to 1 kV or 1 6 nF charged to 5 kV are hazardous live Never touch the measured object during the testing until it is totally discharged Maximum external voltage between any two leads is 600 V CAT Ill environment TeraOhm 5kV 4 Performing measurements 4 1 Switching on the instrument Autocalibration The instrument is switched ON by pressing the ON OFF key After turning on the instrument first executes the autocalibration Fig 5 It is necessary that the measuring test leads are disconnected during autocalibration If not the instrument will require disconnection of the test leads and repeat switching OFF and ON After finishing the autocalibration the instrument is prepared for normal operation Autocalibration prevents lowering of the accuracy when measuring very low currents It compensates the effects caused by ageing temperature and humidity changes etc A new autocalibration is recommended when the temperature changes by more than 5 C TeraOhm 5kV oe TEST LEADS SHOULD BE DISCONNECTED DURING AUTO CALIBRATION 1 gt METREL Software ver 1 7 Fig
20. eplacement of the insulation system is needed Typical examples where testing insulation resistance and its diagnosis are recommended are transformer and motor insulation systems cables and other electrical equipment Electrical representation of insulating material The following figure represents the equivalent electrical circuit of insulating material surface test material 0 TimelSecs 200Secsidiv Riss and Riss2 the surface resistivity position of optional guard connection 12 TeraOhm 5kV Riso the actual insulation resistance of material Ciso capacitance of material Cpi Rpi represents polarization effects The right figure shows typical currents for that circuit kest overall test current hest Ip Ir so Ir ss lp polarization absorption current IRiso actual insulation current Ir ss surface leakage current Some application examples for using Teraohm 5 kV Basic Insulation resistance test Virtually every standard concerning the safety of electrical equipment and installations requires the performance of a basic insulation testing When testing lower values in the range of MQ Ris usually dominates The results are adequate and stabilize quickly The voltage time and limit are usually given in the appropriate standard or regulation The suggested test voltage is often defined as 1 7 times the value of line voltage of the tested device e g motor
21. er current value Actual test current measured value Set Step test time Set End time Actual test time at Stop test voltage Ser number of stored result Date Time 30 TeraOhm 5kV Step voltage Function name Last measured insulation resistance Set test voltage Actual test voltage measured value Actual test current measured value Capacitance of tested object Complete duration of measurement First step measured resistance with its nominal voltage First step actual test voltage measured value Second step measured resistance with its nominal voltage Second step actual test voltage measured value Third step measured resistance with its nominal voltage Third step actual test voltage measured value Fourth step measured resistance with its nominal voltage Fourth step actual test voltage measured value Last step measured resistance with its nominal voltage Last step actual test voltage measured value Ser number of stored result Date Time Note e Date and time of storing the test result are transferred to PC while date and time of recalling are displayed when recalling results 6 2 Data transfer Stored results can be transferred to a PC A special communication program has the ability to identify the instrument and download the data How to transfer the stored data Connect PC COM port to the instrument using the serial communication cable Power up both the PC and the instrument Run th
22. ests Insulating materials are important parts of almost every electrical product The material s properties depend not only on its compound characteristics but also on temperature pollution moisture ageing electrical and mechanical stress etc Safety and operational reliability require the regular maintenance and testing of the insulation material to ensure it is kept in good operational condition For testing the insulation materials high voltage test methods are applied DC vs AC testing voltage Testing with DC voltage is widely accepted as being useful as well as AC and or pulsed DC voltage can be used for breakdown tests especially where high capacitive leakage currents interfere with measurements using AC or pulsed voltage It is mostly applied for measurement tests of the insulation resistance The voltage in this type of test is defined by the appropriate product application group It is lower than the voltage for the withstanding test so the tests can be applied more frequently without stressing the tested material Typical insulation tests In general insulation resistance tests consist of the following possible procedures Simple insulation resistance measurement also called spot test Measurement of voltage dependence of the insulation resistance Measurement of time dependence of the insulation resistance Test of recovered charge after the dielectric discharge The results of this test can indicate whether the r
23. ey or turn the rotary switch to exit this menu Toclear the last stored result select CLR and press the MEM key To clear the complete memory see paragraph 4 2 Configuration In addition to the main result also the subresults and parameters of the selected function are recorded The following is a list of all data stored for each function 29 TeraOhm 5kV List of stored data Voltage Insulation resistance Diagnostic test Withstanding voltage DC Function name Measured voltage Frequency of measured voltage Ser number of stored result Date Time Function name Measured insulation resistance value Set test voltage Actual test voltage measured value Actual test current measured value Capacitance of tested object Duration of measurement Detected maximum value of measured resistance Detected minimum value of measured resistance Ser number of stored result Date Time Function name Last measured insulation resistance Set test voltage Actual test voltage measured value Actual test current measured value Capacitance of tested object Complete duration of measurement Insulation Resistance value taken after elapsed T1 Insulation Resistance value taken after elapsed T2 Insulation Resistance value taken after elapsed T3 DAR value PI value DD value Ser number of stored result Date Time Function name Last measured test voltage Set Start voltage Set Stop voltage Set trigg
24. fective battery please note the following All six cells have to be replaced and they have to be of the same type Turn the power off and disconnect any measurement accessory connected to the instrument before opening the battery cover to avoid electric shock Do not operate the instrument by mains supply without rechargeable batteries in order to avoid permanent damage of internal circuitry Nominal power supply voltage is 7 2 V DC Use six NiCd or NiMH cells with size equivalent to IEC LR14 dimensions diameter 26 mm height 50 mm See the next figure for correct polarity of batteries Fully charged rechargeable battery can supply the instrument for approx 20 hours Note e Standard IEC LR14 type alkaline cells can also be used to replace rechargeable battery Avoid connection to mains supply when alkaline batteries are inserted danger of explosion High quality alkaline batteries can supply the instrument for approx 60 hours 32 TeraOhm 5kV Fig 21 Correct polarity of inserted batteries Notes e Insert cells correctly otherwise test instrument will not operate and battery may be discharged e lf the instrument is not to be used for a long period of time remove all batteries from battery compartment e Take into account handling and maintenance as defined by the manufacturer of battery cells in use 7 3 Cleaning Use a soft cloth slightly moistened with soapy water or spirit to clean the surface of t
25. hange the value of the selected parameter If there are two or more sub parameters in one line e g date and time then use the SELECT key to skip to the next sub parameters and back To clear all memory locations 1 Select Memory Clear line using the T and 4 arrows 2 Press the SELECT key Press MEM to confirm message will be displayed 3 Press the MEM key to clear all memory locations or ESC to cancel the activity Selected function _ a P ban Tue LP ontrast Zn Filter Off Time a en Date 14 Jan 268 F een Baud rate 9688 Memory Clear Initialisation i4 Jan Z006 11 36 N ee Date Time indicator Fig 6 Configuration state Note 0 100 Adjustment of the LCD contrast Fil1 Fil2 Fil8 Selection of noise rejecting filter see the chapter Off 5 3 Filter Option ae Setreal time hour minute t current date day month year pate rate Sass aE 4800 Speed of data transfer in communication mode 9600 19200 Memory clear clear Be Clear all memory locations Initialization For internal factory and service maintenance only internal factory and service For internal factory and service maintenance only only DIAG ee 90 Adjustment of start of timer in DIAGNOSTIC TEST Starting time functions according the Unominal Table 1 Configuration parameters 11 TeraOhm 5kV 5 Measurements 5 1 Generally about DC High voltage testing The purpose of insulation t
26. he instrument and leave the instrument to dry totally before using it Notes e Do not use liquids based on petrol or hydrocarbons e Do not spill cleaning liquid over the instrument 7 4 Calibration It is essential that all measurement instruments be regularly calibrated For occasional daily use we recommend an annual calibration to be carried out When the instrument is used continuously every day we recommend calibrating the instrument every six months 7 5 Service For repairing under or out of warranty period contact your distributor for further information 33 8 Specifications 8 1 Measurements Insulation resistance Nominal test voltage Current capability of test generator Short circuit test current Automatic discharge of tested object TeraOhm 5kV Any within 250 and 5000 V gt 1 mA 1 4 mA max yes Measuring range Riso 0 12 MQ up to 5 TQ Display range Riso Resolution Accuracy 0 999 kQ 1 kQ 1 00 9 99 MQ 10 kQ 10 0 99 9 MQ 100 kQ 100 999 MQ 1 MQ 5 of reading 3 digits 1 00 9 99 GO 10 MQ 10 0 99 9 GO 100 MQ 100 999 GO 1 GQ 1 00 5 00 TQ 10 GQ Full scale value of insulation resistance is defined according the following equation Res 1TQ Uresi kV DC test voltage Voltage value Accuracy Any value within 250 V and 5000 V steps by 50 V 0 10 20 V
27. hows the total measurement period after the completion of the measurement A high voltage warning symbol appears on the display during the measurement to warn the operator of a possible dangerous test voltage Legend of displayed symbols SETTING PARAMETERS SSCS fUstart Jao00v Stari test voltage step 50V fustop 2000v Stoptestvoltage step 50V Tend OOmin 00s Duration of constant test voltage after reaching stop value stop 00min 00s Duration of test voltage per one step Set trigger leakage current step 10 pA 27 TeraOhm 5kV Set up parameters for Withstanding Voltage Press the SELECT key Set up menu appears on display see the figure 19 Select parameter line to be set using the T and 4 keys Adjust set parameter using the lt and keys Skip to the next sub parameter by pressing the SELECT key if there are two or more sub parameters and repeat the adjustment Complete the set up adjustments pressing either the WITHSTANDING VOLTAGE DC SETTING PARAMETERS Ustart M 2008 1 ABANA Admin BGs Admin Ads Fig 19 Set up menu in ESC key or START key to run the measurement Withstanding Voltage function directly or changing the rotary switch position The last displayed settings are stored Tstep and Tend are independent timers The maximum time for each timer is 30 min 60 s Tend begins after the completion of the ramp period Ramp period can
28. i e the test voltage for a 600 V device would be 1020 VDC Measuring time should be set to 60 s or the minimum time required for the Ciso to be charged up Sometimes it is required to take into account the ambient temperature to adjust the result for a standard temperature of 40 C If surface leakage currents interfere with the measurements see Riss above use the guard connection see 5 2 This becomes critical when measuring values in the GQ range Some examples Standard Test voltage time End value EN IEC 60204 500 V 1 MQ EN IEC 60335 1 2000 V 15 min EN IEC 60349 1 500 V 1000 O V EN IEC 60598 1 500 V 1s 2 MQ Only sample values are listed Voltage dependence test Step voltage test This test shows if the insulation under test has been electrically or mechanically stressed In this instance the quantity and size of insulation anomalies such as cracks local breakdowns conductive parts etc is increased and the overall breakdown voltage is reduced Excessive humidity and pollution have an important role especially in the case of mechanical stress The test voltage steps are usually close to those required in the DC withstanding test Sometimes it is recommended that the maximum voltage for this test should not be higher than 60 of withstanding voltage If the results of successive tests show a reduction of the tested insulation resistance the insulation should be replaced
29. l applicable values Tested material status 1 to 1 5 Not acceptable older types 2 to 4 typically 3 Considered as good insulation older types 1 very high insulation resistance Modern type of good insulation systems Example for minimum acceptable values for motor insulation IEEE 43 Class A 1 5 Class B 2 0 Class F 2 0 Class H 2 0 DIELECTRIC DISCHARGE An additional effect of polarization is the recovered charge from Cpi after the regular discharging of a completed test This can also be a supplementary measurement for evaluation of the quality of insulating material This effect is generally found in insulating systems with large capacitance Ciso Tested material status gt 4 tba o O 14 TeraOhm 5kV Withstanding voltage test Some standards allow the use of a DC voltage as an alternative to AC withstanding voltage testing For this purpose the test voltage has to be present across the insulation under test for a specific time The test result passes if there is no breakdown or flash over Standards recommend that the test starts with a low voltage and reaches the final test voltage with a slope that keeps the charging current into Ciso under the limit of the current threshold The test normally takes 1 min Withstanding voltage test or dielectric test is usually applied for Type acceptance tests when a new product is prepared for manufacture Routine production test for verification of the
30. late DAR Time3 Time node to take RO3min result and calculate PI DD on off ON DD enabled OFF DD disabled Timel Time2 and Time3 are timers with the same start point The value of each presents the duration from the start of the measurement Maximum time is 30 min The following figure shows the timer relationship SSS SSO ee 0 Time 1 Time2 Time3 t Start Stop R15s RO1min RO3min DAR PI if enabled DD Time1 lt Time2 Time2 lt Time3 Fig 13 Timer relations Warning e Refer to Warnings chapter for safety precautions 23 TeraOhm 5kV 5 7 Step Voltage Insulation Resistance testing Selecting this function displays the following states initial state and state with results after the completion of the measurement STEP VOLTAGE 497 750V U 8104 M amp 1 1 62HA m 85min 88s 64uF SOUS 115m Ui OGR U2 a 17 Jan 2000 11 32 Initial display Display with results Fig 14 Step Voltage Insulation Resistance function display states Insulation is measured in five equal time periods at test voltages from one fifth up to full scale see the figure 15 This function shows the level of the measured Insulation Resistance versus the test voltage Measurement procedure Connect the test leads to the instrument and to the measured object Press the START key to start the measurement Wait until set timer runs out result is displayed Wait until the object under test has discharged The result
31. on of the measurement tr while after the completion the test duration tm is displayed A high voltage warning symbol appears on the display during the measurement to warn the operator of a possible dangerous test voltage Value of capacitance is measured during the final discharge of the measured object Set up parameters for Insulation Resistance INSULATION RESISTANCE Press the SELECT key Set up menu appears on SETTING PARAMETERS display see the figure 10 nominal W Select parameter line to be set using the T and 4 Timer 16min 68s i Timer onzoff ON keys Timel Bimin Ads Adjust set parameter using the lt and keys Skip to the next sub parameter by pressing the SELECT key if there are two or more sub parameters and repeat the adjustment Complete the set up adjustments pressing either the Fig 10 Set up menu in ESC key or START key to run the measurement Insulation Resistance directly or changing the rotary switch position Last measurement displayed settings are stored 19 TeraOhm 5kV Legend of displayed symbols INSULATION RESISTANCE Name of selected function l SETTING PARAMETERS S Unominal 1000v _ Settestvoltage step 50V Cd ON timer enabled OFF timer disabled Timel Olmin 00s Time to accept and display first Rmin and Rmax result Timer and Timel are independent timers Maximum time for each of them is 30 min 60 s Warning e Refer to Warnings chapter for s
32. ove the noise reduction Example 2 Testing an object with the following parameters Utest 250 V Inoise 3 mA R 2 4 GQ C 220 nF Filter options give following results OFF distribution of results 30 Fil1 distribution of results 3 5 Fil2 distribution of results 1 5 Fil3 distribution of results 0 9 For this example the setup time is also increased and for the Fil3 option the time to capture the first good result Time1 is approximately 2 min TeraOhm 5kV 5 4 Voltage measurement Selecting this function displays the following states initial state and state with results after completion of the measurement f _ 2 1 6 v f 50 GHz 100U 2000 3000 oov S000 eooy ov 1000 2000 3000 oov Soov oou Initial display Display with results Fig 8 Voltage function display states Measurement procedure Connect the test leads to the instrument and to the measured source Press the START key to start the measurement continuous measurement starts to run Press the START key again to stop the measurement The result see the right figure above can optionally be saved by pressing the MEM key twice see the chapter 6 1 Store Recall and Clear Operation Warning e Refer to Warnings chapter for safety precautions 5 5 Insulation Resistance measurement Selecting this function displays the following states initial state and state with results after the completion of the measurement INSULATIO
33. pment may be impaired Do not use the instrument and accessories if any damage is noticed Consider all generally known precautions in order to avoid the risk of electric shock while dealing with electric installations Service intervention or recalibration procedure can be carried out only by a competent and authorized person Only adequately trained and competent persons may operate the instrument BATTERIES Disconnect all test leads and switch the power off before opening the Battery cover Avoid connection to main supply when alkaline batteries are inserted danger of explosion Do not charge when alkaline batteries are fitted EXTERNAL VOLTAGES Do not connect the instrument to a mains voltage different from the one defined on the label adjacent to the mains connector otherwise the instrument may be damaged e Do not connect test terminals to an external voltage higher than 600 V AC or DC CAT Ill environment to prevent any damage on the test instrument WORKING WITH THE INSTRUMENT Use only standard or optional test accessories supplied by your distributor Equipment under test must be switched off i e de energized before test leads are connected to the equipment Do not touch any conductive parts of equipment under test during the test Make sure that the tested object is disconnected mains voltage disconnected before starting the Insulation Resistance measurement e Do not touch the tested obj
34. red object tr 00min 15s Set timer value Analog presentation of Riso result D A gt 1TQ i Resistance value measured after set time 2 Resistance value measured after set time 3 Resistance value measured after set time 1 DAR as ratio ofR01min R15s PI as ratio of R03 R02 22 TeraOhm 5kV Notes A high voltage warning symbol appears on the display during the measurement to warn the operator of a possible dangerous test voltage The value of capacitance is measured during the final discharge of the measured object If enabled the instrument measures DD when the measured capacitance is in the range of 5 nF to 50 uF Set up parameters for Diagnostic Test DIAGNOSTIC TEST Press the SELECT key Set up menu appears on SETTING i i LUnominal BYE display see the figure 12 Jii Mana I Select parameter line to be set using the T and 4 Time2 azmin Times 83min keys DD on off ON Adjust set parameter using the lt and keys Complete the set up adjustments pressing either the ESC key or START key to run the measurement directly or changing the rotary switch position Last displayed settings are stored Fig 12 Set up menu in Diagnostic Test Legend of displayed symbols DIAGNOSTIC TEST Name of selected function SETTING PARAMETERS O 1000V_ __ Set test voltage step 50 V Time1 Time node to take RO1min result Time2 Time node to take RO1min result and calcu
35. s with the measurement i e the Insulation Resistance result is influenced by this current The GUARD terminal is internally connected to the same potential as the negative test terminal black one The GUARDs test alligator should be connected to measured object so as to collect most of the unwanted leakage current see the figure below 15 TeraOhm 5kV Fig 7 Connection of GUARD terminal to measured object an example for measuring cable insulation is shown where N een Test voltage een Leakage current resulted by surface dirt and moisture IM Material current resulted by material conditions Rss A meter current Result without using GUARD terminal Rins Ut IA Ut Im IL incorrect result Result using GUARD terminal Rins Ut la Ut Im correct result It is recommended to use the GUARD connection when high insulation resistance gt 10G Q is measured Note e Guard terminal is internal impedance 300 KQ protected 5 3 Filter option Filters are built in to reduce the influence of noise on measurement results This option enables more stable results especially when dealing with high Insulation Resistances The table below contains a definition of the individual filter options 16 TeraOhm 5kV Filteroption Meaning S O Off Low pass filter with cut off frequency of 0 5 Hz in signal line Additional low pass filter with cut off frequency of 0 05 Hz in signal
36. safety of each product Maintenance and after service test for any equipment the insulation system of which is affected to possible degradation Some examples for DC withstanding test voltage values Standard only sample values Voltage EN IEC 61010 1 CAT II 300 V basic insulation 1970 V EN IEC 61010 1 CAT II 300 V double insulation 3150 V IEC 60439 1 clearance between live parts withstanding impulse voltage 4 kV 500 m 4700 V IEC 60598 1 2120 V Humidity and insulation resistance measurements The quality of insulation resistance measurements outside the reference ambient conditions could be affected by humidity Humidity adds leakage paths onto the surface of the complete measuring system i e insulator under test test leads measuring instrument Its influence reduces tolerances especially in the very high resistance range tera ohms The worst conditions arises in case of condensation which can also reduce the safety In the case of high humidity it is recommended to ventilate the test areas before and during the measurements In the case of condensed humidity the measuring system must dry and it could take several hours or even few days to recover 5 2 Guard terminal The purpose of the GUARD terminal is to lead away potential leakage currents e g surface currents which are not a result of the measured insulation material itself but of the surface contamination and moisture This current interfere
37. section by means of a plastic cover 2 2 3 4 5 6 BONET Gana ast coun evn Ra CELLS ponens aA AANEEN 7 STROMVERSORGUNG e e ca mm A onan LR 14 Fig 3 Bottom section Legend less Nylon strap allows the operator to carry the instrument hung around the neck Peete Plastic cover fixes the nylon strap to the instrument C Screw unscrew to remove the carrying strap or to open the instrument eee Label with measurement ranges Iiei Battery fuse compartment cover Oira Screw unscrew to replace the batteries Tonaaaaaan Rubber foot 2 5 Accessories The accessories consist of standard and optional accessories Optional accessories can be delivered upon request See attached list for standard configuration and options or contact your distributor or see the METREL home page http www metrel si TeraOhm 5kV 3 Warnings In order to reach the highest level of operator s safety while carrying out various measurements and tests using the TeraOhm 5kV Tester as well as to ensure that the test equipment remains undamaged it is necessary to consider the following warnings MEANING OF SYMBOLS N symbol on the instrument means Read the User Manual with special care A symbol on the instrument means Hazardous voltage higher than 1000 V may be present at the test terminals GENERAL PRECAUTIONS If the test equipment is used in a manner not specified in this Users Manual the protection provided by the equi
38. see the figure 16 animal ALLEN Select parameter line to be set using the T and 4 keys Adjust set parameter using the lt and keys Complete the set up adjustments by pressing either the ESC key or START key to run the measurement directly or changing the rotary switch position Last Fig 16 Set up menu in Step displayed settings are stored Voltage Test Legend of displayed symbols STEP VOLTAGE Name of selected function SETTING PARAMETERS 1000V Set test voltage step 250 V Duration of measurement per step 25 TeraOhm 5kV Note Maximum value for Step Time is 30 min Warning e Refer to Warnings chapter for safety precautions 5 8 Withstanding voltage This function offers Withstanding Voltage test of insulation material It covers two types of tests a Breakdown voltage testing of high voltage device e g transient suppressors and b DC withstanding voltage test for insulation coordination purposes Both functions require breakdown current detection The test voltage increases step by step from the Start up to the Stop value over a predefined time and it is kept at the Stop value for a predefined test time see the figure below Ustop Ustep Ustart Ustart Tstep Tend Fig 17 Test voltage presentation without breakdown left part and with breakdown right part Ut Test voltage Ustop End test voltage Ustep Voltage step approx 20 V fixed value not preset
39. tage To avoid this problem increase DIAG Starting time parameter in CONFIGURATION menu because start of timer in DIAGNOSTIC TEST functions depends on output test voltage Timer begins to run when output test voltage reaches threshold voltage which is product of parameters DIAG Starting time and Unominal nominal test voltage Using filters fil1 fil2 fil3 in DAR function is not recommended Analyzing trend of measured insulation resistance and calculation of DAR and PI are very useful maintenance tests of insulating material POLARIZATION INDEX PI Pl is the ratio of Insulation Resistance values measured after 1 minute and after 10 minutes The DC test voltage is present during the whole period of the measurement also Insulation Resistance measurement is running On completion of the test the PI ratio is displayed R 10min R 1 min Note When determining Riso 1min pay close attention to the capacitance of the object under test It has to be charged up in the first time section 1 min Approximate maximum capacitance using PI C url t HO 3 U VI where PERF period of first time unit e g 1min U een test voltage To avoid this problem increase DIAG Starting time parameter in CONFIGURATION menu because start of timer in DIAGNOSTIC TEST functions depends on output test 21 TeraOhm 5kV voltage Timer begins to run when output test voltage reaches threshold voltage which is product of parameters
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