AEMC Instruments AEMC 2620 Current Transformer Manual
Contents
1. Cat 1017 45 Converts male safety plugs to non shielded male plugs Bag Large Classic Tool Bag aaaiaiaiaaaasasaasaasssnssnna Cat 2133 71 1 800 561 8187 www Geld com information itm com 4 Ground Fault Leakage Detector Model 2620 CHAPTER 2 PRODUCT FEATURES 2 1 Description The Model 2620 measures leakage current shunted to ground caused by insulation breakdown or leaks It enables the operator to locate failures when or before they occur without shutting down equipment or spending hours trouble shooting It is designed specifically for locating low current faults on high current loads The detector is a sensitive AC current transformer capable of mea suring differential or leakage current from 500MA and may be used to measure current up to 400A continuous duty The Model 2620 provides on two ranges 1mV mAac or 1mV Aac The output leads are terminated with standard 4mm banana plugs capable of interfacing with any standard multimeter Use of a digital multimeter with analog bar graph is recommended Digital to provide the proper voltage input impedance and an analog bar graph to track trends When the 2620 is used as a currentleakage detector it makes no difference if the system is single phase or poly phase or if the currents are in phase or out of phase balanced or unbalanced The net magnetic field at any instant in time will be zero if all the conductors surrounded by the current leakage2. 1 800 561 8187 www GED com information itm com Zane EVE wy ENGLISH User Manual had INSTRUMENTS XC X 43 j Statement of Compliance X g X 43 Jt Chauvin Arnoux Inc d b a AEMC Instruments Ke certifies that this instrument has been calibrated ig using standards and instruments traceable to i X international standards YE N E We guarantee that at the time of shipping your ae NO instrument has met its published specifications ay Af 43 An NIST traceable certificate may be i requested at the time of purchase or obtained WO by returning the instrument to our repair and x ii calibration facility for a nominal charge i DU N The recommended calibration interval for this We No instrument is 12 months and begins on the date of a X receipt by the customer For recalibration please y use our Calibration services Refer to our repair X Y and calibration section at www aemc com YC X J 5 X Serial X Catalog 2125 52 X V YC l Model 2620 1 Ap y No YC i Please fill in the appropriate date as indicated lt l Date Received Y 5 i K Date Calibration Due X MM M 0 X YC Chauvin Arnoux Inc YC d b a AEMC Instruments 1 ag did INSTRUMENTS WWW aemc com A 1 800 561 8187 www an com information itm com BEA EE ER ELE eee Table of Contents 1 INTRODUCTION eene see see Re ER ERK ERK ERA KRAKE RR ER GEK KERR KEER KERE 3 1 1
3. Check that the edges of the jaws are perfectly clean and that they close tightly Try to avoid placing the conductors near the gaps and group them as much as possible If you are careless you can affect the magnitude of the reading depend ing on the current being carried in the conductors In certain cases this requires an interpretation Normally however the absolute value of the ground current is not important All you need to know is whether the read ing is Zero 4 3 Testing Various Cable Configurations Older installations have a wide variety of electrical distribution systems Cables are clamped to walls and pass through metal conduits and there are many cases where a shielded cable was installed during revamping of an area or addition to a building If a cable is clamped to walls detach it and pull it away from the surface at several points so the clamp can sur round all the conductors 4 3 1 Metal Conduits Cables enclosed in metal conduits which are grounded are not a problem Simply apply the clamp around the conduit the metal tube will not block the measurement Cables with a metal shield can be handled in the same way as cable in metal conduit A grounded shield may present a problem If it is a simple metal shield like a thin metal wrapping it can be considered in the same way as the metal conduit If the armor is grounded by a conductor it may be an inconve nience depending on the terminal connections as well
4. EN 61010 600V Cat III Pollution Degree 2 Electromagnetc Compatibility Industrial Environment Criterion B Emissivity EN 61326 1 Susceptibility EN 61326 1 Self extinguishing Capability Jaws and Casing VO UL 94 1 800 561 8187 www GED com information itm com Ground Fault Leakage Detector Model 2620 9 CHAPTER 4 OPERATION 4 1 Principle of Operation 4 1 1 Measuring Current Leakage When a generator supplies an AC load through a pair of wires in an insulated cable the current going out on one wire is equal to the current returning their vector sum equals zero A ground fault changes this equality and the leakage current detector picks it up measures it and provides an AC voltage output proportional to the severity of fault causing the unbalance The ground conductor must not pass through the detector 4 1 2 Interpreting the Measurement Figure 1 is a schematic of a single phase installation of a motor and an oven both grounded The numbers indicate the amplitudes of the currents in different conductors This installation has no faults If you clamp the detector around the cables at points A B C or D it will output zero ZERO AMPERE PNO enn 1 800 561 8187 www GED com information itm com 10 Ground Fault Leakage Detector Model 2620 In Figure 2 there is a fault in the installation At point A the Model 2620 detects 1A the difference between 16A and 15A indicating a fault downstream At poin
5. detector are supplying all the current delivered to and received from the load If any current is diverted through any alternate path to ground such as an insulation breakdown the net loss will be detected producing a output proportional to the amplitude of the fault current The Model 2620 may also be used simply as a highly accurate clamp on current probe With its 4 jaw opening and range of 500pA to 400A the 2620 provides a versatile way to analyze unbalanced current measurements leakage values on grounding conductors and ground loop currents 1 800 561 8187 www GED com information itm com Ground Fault Leakage Detector Model 2620 5 2 2 Connections The Model 2620 is compatible with most DMMs voltmeters or other voltage measuring instruments with the following features e Range and resolution capable of displaying 1mVAc of input e Voltmeter accuracy of 0 75 or better to take full advantage of the accuracy of the probe e Minimum input impedance of 1MQ Connect the probe to the multimeter or other instrument Select the appropriate AC voltage range on your multimeter The Model 2620 has two selectable output ranges The 4A range will pro duce a mV mA with an output of 4VAc at 4A The 400A range produces 1mV A with 40OmVac at 400A A Warning User Safety Always use a DMM voltmeter or other displaying device appropriately rated for the working voltage and for safety 1 800 561 8187 www GED com information itm co
6. on digital multimeter place the switch in the slow position when using an analog multimeter set the switch to the fast position An internal buzzer also driven by the relay is activated each time the neutral connection is grounded Three lights one for each phase show the presence of each of the three phases in the Artificial Neutral prior to measurement A fourth green light indicates the instrument is operating Safety alligator clips Male male safety leads 4 mm length 5 ft 1 5 m double insulation ON light green Carrying Strap to 65Hz Batteriqh 8 x 1 5V AA LI EN 61910 600V Cat Ill Pol 2 AEMC 3 position switch ON Slow test Red light showing OFF Ventilation holes voltage present and ON Fast test phase fault Carrying case not shown Figure 8 1 800 561 8187 www GED com information itm com 18 Ground Fault Leakage Detector Model 2620 5 2 Specifications 5 2 1 Electrical Working Voltage 30 to 600V Frequency 45 to 65Hz Resistance Per Phase 3 9kQ 5 Relay Duty Time Slow position 0 5 s Fast position 2 3 s Power Source Eight 1 5V AA batteries Power Consumption 180mA approx Average Battery Life 40 hours 5 2 2 Mechanical Reference Temperature 23 C 3 C Operating Temperature 32 to 122 F 0 to 50 C 10 to 90 RH Storage Temperature 40 to 158 F 40 to 70 C 10 to 90 RH Case Fire resistant polycarbonate UL94 Color Yellow
7. 0 561 8187 www GED com information itm com CJAEMC INSTRUMENTS 05 09 99 MAN 100292 v4 1 800 561 8187 www GE com information itm com 15 Faraday Drive Dover NH U38ZU USA Phone 6U3 49 6434 Fax 6U3 42 2346 www aemc com
8. ARNING For maintenance use only specified factory replacement parts e To avoid electrical shock do not attempt to perform any servicing unless you are qualified to do so e To avoid electrical shock and or damage to the instrument do not get water or other foreign agents into the case Turn the instrument OFF and disconnect the unit from all the circuits before opening the case 6 1 Cleaning e Wipe the case and jaw covers with a lightly moistened cloth and mild detergent e Do not use any abrasives or solvents Ifrusted the jaw mating surfaces of the Model 2620 may be lightly sanded with very fine sandpaper and then very lightly oiled Wipe off excess oil and do not let it drip into the case 1 800 561 8187 www GED com information itm com 22 Ground Fault Leakage Detector Model 2620 Repair and Calibration To ensure that your instrument meets factory specifications we recommend that it be scheduled back to our factory Service Center at one year intervals for recalibration or as required by other standards or internal procedures For instrument repair and calibration You must contact our Service Center for a Customer Service Authorization Number CSA This will ensure that when your instrument arrives it will be tracked and processed promptly Please write the CSA on the outside of the shipping container If the instrument is returned for calibration we need to know if you want a standard calibration or a calibr
9. Dimensions 8 7 x 5 4 x 5 9 220 x 136 x 150mm Weight 2 9 Ibs 1 3kg 5 2 3 Safety Dielectric Strength Test 6kV between terminal and case C ol 600V Cat III 1 800 561 8187 www HU II com information itm com Ground Fault Leakage Detector Model 2620 19 5 3 Principle of Operation If there is not an insulation fault on the system no leakage current will flow to ground The vector sum of the currents flowing through the three con ductors enclosed within the clamp is zero The display will indicate zero see Figure 9 source I load i Figure 9 If there is a fault a leakage current then flows between the faulty phase and ground The detection of this fault current on an ungrounded system will be intermittent as determined by the rate of relay closure Figure 10 source AN load current clamp Figure 10 Due to the fault current the vectorial sums of the current will no longer be zero Fault current will be indicated by the selection on the Model 2620 1 800 561 8187 www GED com information itm com 20 Ground Fault Leakage Detector Model 2620 5 4 Testing Ungrounded Systems Before starting ensure that the Artificial Neutral batteries are in good con dition Switch on the instrument Fast or Slow The green light must be illuminated and the buzzer must be activated at the selected rate If the green light is out or if the buzzer sounds weak replace the batteries Switch t
10. International Electrical Symbols ees se eed ee ee ee ee ee ee 3 1 2 Definition of Measurement Categories s 4 1 3 Receiving Your Shipment cece ee ee RA ee 4 1 4 Ordering Information aiana 4 1 4 1 Accessories and Replacement Parts 4 2 PRODUCT FEATURES 222222aaaaanaann n nannnnnnnnnnnnnnnnnnn n 5 21 De dele AE RE OE EE aa 5 2 2 GONNECUOIS EE EER ee ee ee deed et ae SE a ee de Ee 6 3 SPEGIFICATIONS uuseee sees see eke KERE RR KEER RE ER KK ERK KEER KEER RR EE KERE RR KEER 7 3 1 Reference Conditions ee ee RR RR ee Ge RR ee 7 3 2 ee OE ER EE OE 7 3 3 Ie le AE EE N EE EE EE N 8 34 Environmental iaaaiaaaxanaiannnannnnnnnnnnnnnnnnnnnnnnnunnnnnannnnnnnunaa 9 Sid RR EE EE ceed ihan edad eae 9 4 OPERATION csscecssseesneeessseesseessseeessnensneeessneesneesssneeenneeseneeeas 10 4 1 Principle of Operation ee ee ee ee RR RA AR Re ee ee ee ee ee 10 4 1 1 Measuring Current Leakage ie ee ek ee ee 10 4 1 2 Interpreting the Measurement ee ee 10 4 2 Equipment Troubleshooting iii ee ee ee RR Re Ee ee 11 4 3 Testing Various Cable Configurations 12 4 34 Metal ConduitS ei Ee SEER EE RAK tenia e 12 4 3 2 Grounded Neutral ie ee ee RR ee 14 4 3 3 Neutral Grounded Through an Impedance 15 4 3 4 Ungrounded System ee ee Re ee ee ee 15 4 4 Commonly Asked OuestiOnS
11. ad Impedance DMM 1MQ min Frequency 48 to 1000Hz Errors caused by external influences Ambient temperature lt 0 1 per 10K Position of the gripped conductor 0 1 typic of VouT non differential max with not centred conductor current 0 2 max Residual differential 0 1 typic of IP differential current max with not centred conductor 0 2 max External fields 1V A lt 60mV of Vs External fields 1mV mA lt 100uV of Vs Coupled DC current 1V A 2 lt 1mV for continuous 1A Coupled DC current 1mVm A 2 lt 0 1mV for continuous 1A Frequency 1V A lt 1 5 from 30Hz to 1KHz Frequency 1mV mA lt 0 5 from 30Hz to 1KHz 1 400 A m 50Hz field perpendicular to the clamp opening 2 DC current coupled onto an AC current 3 Limited to 1KHz for 100A 3 3 Mechanical Dimensions 11 2 x 6 9 x 1 8 285 x 175 x 45mm Weight 2 9 lbs 1300g approx Jaw opening 4 4 112mm Maximum Jaw Gap 9 8 250mm Maximum Clamping Capacity Max 4 5 115mm cable 1 800 561 8187 www GED com information itm com 8 Ground Fault Leakage Detector Model 2620 34 Environmental Operating Temperature 14 to 131 F 10 to 55 C 0 to 85 RH non condensing Storage Temperature 40 to 158 F 40 to 70 C 0 to 85 RH non condensing Operating Altitude lt 2000m on uninsulated conductors Transport Altitude lt 12000m 3 5 Safety Electrical Safety ce ol
12. as on the number and type of ground connections along the cable In Figure 3 the detector senses the fault because the shield is not con nected to the motor frame and the leakage current cannot flow back through the detector In Figure 4 however the instrument cannot see the fault because the shield is connected to the motor frame letting the fault current return through the detector and causing it to read zero If possible take your measurement where you can avoid closing the shield in the clamp such as the nearest control panel or inside the connecting box of the motor 1 800 561 8187 www GED com information itm com 12 Ground Fault Leakage Detector Model 2620 Figure 3 Figure 4 One way to circumvent this shielded cable problem is shown in Figures 5 and 6 Here the shield is looped through the detector twice so that the reading will be that of the fault current Figure 5 Figure 6 1 800 561 8187 www GED com information itm com Ground Fault Leakage Detector Model 2620 13 4 3 2 Grounded Neutral It is easy to take measurements on this type of network where major faults trip the circuit breaker Here the detector can sense minor faults so repairs can be made before the problem gets worse The inspection method is the same as for a single phase installation Remember that on a three phase network the currents add according to the vector sum law The Model 2620 measures the vector sum of the enc
13. ated to service not performed by AEMC Instruments For full and detailed warranty coverage please read the Warranty Coverage Information which is attached to the Warranty Registration Card if enclosed or is available at www aemc com Please keep the Warranty Coverage Information with your records What AEMCY Instruments will do Ifa malfunction occurs within the one year period you may return the instrument to us for repair provided we have your warranty registration information on file or a proof of purchase AEMC Instruments will at its option repair or replace the faulty material REGISTER ONLINE AT www aemc com Warranty Repairs What you must do to return an Instrument for Warranty Repair First request a Customer Service Authorization Number CSA by phone or by fax from our Service Department see address below then return the instrument along with the signed CSA Form Please write the CSA on the outside of the shipping container Return the instrument postage or shipment pre paid to Ship To Chauvin Arnoux Inc d b a AEMC Instruments 15 Faraday Drive s Dover NH 03820 USA Phone 800 945 2362 Ext 360 603 749 6434 Ext 360 Fax 603 742 2346 or 603 749 6309 E mail repair aemc com Caution To protect yourself against in transit loss we recommend you insure your returned material 1 800 561 8187 NEE EED com information itm com 24 Ground Fault Leakage Detector Model 2620 1 80
14. ation traceable to N I S T Includes calibration certificate plus recorded calibration data Ship To Chauvin Arnoux Inc d b a AEMC Instruments 15 Faraday Drive Dover NH 03820 USA Phone 800 945 2362 Ext 360 603 749 6434 Ext 360 Fax 603 742 2346 or 603 749 6309 E mail repair aemc com Or contact your authorized distributor Costs for repair standard calibration and calibration traceable to N I S T are available NOTE You must obtain a CSA before returning any instrument Technical and Sales Assistance If you are experiencing any technical problems or require any assistance with the proper operation or application of your instrument please call mail fax or e mail our technical support team Chauvin Arnoux Inc d b a AEMC Instruments 200 Foxborough Boulevard Foxborough MA 02035 USA Phone 800 343 1391 508 698 2115 Fax 508 698 2118 E mail techsupport aemc com www aemc com NOTE Da not chin Inetrimeantes ta our Fovhaoraouah MA address u 1 800 561 8187 www Ie IM com information itm com Ground Fault Leakage Detector Model 2620 23 Limited Warranty The Model 2620 is warranted to the owner for a period of one year from the date of original purchase against defects in manufacture This lim ited warranty is given by AEMC Instruments not by the distributor from whom it was purchased This warranty is void if the unit has been tam pered with abused or if the defect is rel
15. bution level such as on hardwired equipment in fixed installation and circuit breakers Cat IV For measurements performed at the primary electrical supply lt 1000V such as on primary overcurrent protection devices ripple control units or meters 1 3 Receiving Your Shipment Upon receiving your shipment make sure that the contents are consistent with the packing list Notify your distributor of any missing items If the equip ment appears to be damaged file a claim immediately with the carrier and notify your distributor at once giving a detailed description of any damage Save the damaged packing container to substantiate your claim 1 4 Ordering Information Ground Fault Leakage Detector Model 2620 Cat 2125 52 Includes user manual and warranty card 1 4 1 Accessories and Replacement Parts Artificial Neutral Model AN 1 aaaazaazaaaaaaaaaaaaaaaaaaananaaanannaaaaai Cat 1971 01 Includes instrument with soft carrying case eight 1 5 V AA batteries four 5 ft 1 5 m color coded leads green red black blue four color coded alligator clips green red black blue and user manual Lead Replacement aiiiaaaaaaasassannannannnnannassnnnnnna Cat 2950 29 Set of 4 Color coded 5 ft Safety Leads 4mm straight banana plugs on both ends 4 Color coded safety alligator clips for use with the Artificial Neutral Model AN 1 Adapter 4mm Non insulated for Safety Leads
16. d within the clamp jaws e Stay away from other conductors which may create interference Avoid leaving the clamp in damp places or exposing it to running water e Due to shock or fire hazards electrical connections of the instrument should be performed only by qualified personnel and in accordance with local state and federal electrical requirements 1 1 International Electrical Symbols E This symbol signifies that the instrument is protected by double or reinforced insulation Use only specified replacement parts when servicing the instrument A This symbol on the instrument indicates a WARNING and that the operator must refer to the user manual for instructions before operating the instrument In this manual the symbol preceding instructions indicates that if the instructions are not followed bodily injury installation sample and product damage may result 1 800 561 8187 _ www BE fT com information itm com j oe Ground Fault Leakage Detector Model 2620 3 1 2 Definition of Measurement Categories Cat 1 For measurements on circuits not directly connected to the AC supply wall outlet such as protected secondaries signal level and limited energy circuits Cat II For measurements performed on circuits directly connected to the electrical distribution system Examples are measurements on household appliances or portable tools Cat Ill For measurements performed in the building installation at the distri
17. he Artificial Neutral from its carrying case The Artificial Neutral must always be in the OFF position when con necting the leads Always make connections from the instrument to the circuit under test Always inspect the instrument and accessory leads for serviceability prior to use Replace defective parts immediately Never use the instrument on electrical conductors rated above 600V 5 1 Description The Artificial Neutral is an accessory for the AEMC Model 2620 Ground Fault Leakage Detector It generates a grounded artificial neutral to allow the measurement of fault currents on ungrounded 3 phase systems In an ungrounded system the impedance between the transformer neu tral and ground is infinity Therefore independent of the load current no ground fault current should flow The Artificial Neutral creates an intermittent return path for the ground fault current enabling the troubleshooter to distinguish it from load current The Artificial Neutral is grounded intermittently through a relay driven by an internal clock This periodic grounding technique performs three func tions e Limits the possibility of insulation faults within the case 1 800 561 8187 www GED com information itm com LIMITS INSITUMENT overneaung Ground Fault Leakage Detector Model 2620 17 Relay closure time is selected externally Fast or Slow so that the ground fault clamp can be used on either an analog or digital display When using
18. he instrument OFF green light off Connect the leads to the appropriate phases of the system under test At this point do not connect the Artificial Neutral to ground Phase A RED Phase B BLACK Phase C BLUE Switch the instrument ON Fast or Slow The three phase lights must come on at the same time then periodically at the same rate as the buzzer If one or more do not light stop the test and verify connections or the existence of a phase fault Note There must be at least 30V between phases After verifying that all the lights have illuminated properly turn the instru ment OFF and connect the GROUND lead to a known good ground To measure the value of the fault connect the Model 2620 to a multime ter with an appropriate measurement range Enclose the three phase conductors within the jaws Switch ON the Artificial Neutral Fast or Slow depending on the response time of the measuring instrument The actual fault measurement must be made when the instrument relay is closed e g when the buzzer sounds The measured value when the relay is closed is the actual value of the fault current depending on the selected output signal To disconnect the Artificial Neutral reverse the procedure Switch the Artificial Neutral OFF disconnect the GROUND lead then disconnect each one of the phase leads 1 800 561 8187 www GED com information itm com Ground Fault Leakage Detector Model 2620 21 CHAPTER 6 MAINTENANCE A W
19. ie ee ee ee ee ee ee 15 5 ARTIFICIAL NEUTRAL e sees sees see seek Ke Re EK ERGER KEER KEER KERE KERE ee EE 17 El ER Ed 17 oT oe ie el AE N RE EE EE EE vias 17 1 800 561 8187 wa GED com information itm com 5 2 SPECICATION AE EE HE E 19 5 2 1 Bleetmoal iis Re Re DA NR ARE ee ee ee ee ha eg 19 522 Ve le HER OR OE OE RE OE EE 19 Pe MS AE 19 5 3 Principle of Operation iii ee ER AA Ee ee ee RA Re de ee 20 5 4 Testing Ungrounded Systems ese ee Re ee AR Re ee 21 6 MAINTENANCE eeesseee sees sae ek Ke ER ERK ERA RR ERK ERGER KEER KEER KERE REGEER EE 22 6 1 oe EE EE ER EE RR OE 22 Repair and CalibratiON ee ee ee ER ER RA AA Re Ee ee ee RR Ee Re AA ee ee ee ee 23 Technical and Sales Assistance ee ee ee Re ee ee Re ee ee Re ee ee 23 Limited El LL EE AE EE N 24 Warranty Repairs ees de ee ee de ee ee AR Re ee ee ee Re ee ee ee Re ee ee ee ee ee 24 1 800 561 8187 wa GED com information itm com CHAPTER 1 INTRODUCTION A Warning A These safety warnings are provided to ensure the safety of person nel and proper operation of the instrument e Never use this clamp on conductors with a voltage potential above 600Vrms e Never clamp around a conductor unless the clamp is terminated to a measuring instrument with proper input impedance e Keep the jaw mating surfaces clean If necessary use a slightly oiled cloth to remove oxidation Ensure that the cables or bus bar are properly centere
20. losed currents If you have for example a 400mA fault and a 250mA fault on the same phase the Model 2620 will detect 650mA But if the two faults are on different phases they add vectorially and may even sum up to zero Figure 7 shows an example in which there are two separate faults 400mA on a machine in one shop 250mA on a machine in another shop The vector sum is not 650mA but 350mA If you switch off the machine with the 250mA fault the reading increases indicating faults on different phases Shop 1 Fault on Phase 1 panna ee eae 400mA Fault on Phase 2 250mA Figure 7 1 800 561 8187 wa GED com information itm com 14 Ground Fault Leakage Detector Model 2620 4 3 3 Neutral Grounded Through an Impedance Follow the procedure the same way as for a grounded neutral installation but with care When the neutral is grounded through an impedance a fault even a serious one may not trip the circuit breaker and the circuit will stay live 4 3 4 Ungrounded System In order to measure on an ungrounded system the optional Artificial Neutral Model AN 1 must be used in conjunction with the Model 2620 For measurement procedures see the information in this manual in Chapter 5 4 4 Commonly Asked Questions Q I have found an indication of 40 to 50mA on one of the main feed ers with 300A on the line Is this value a fault A With 300A on the line it is possible to find an undesired cur
21. m 6 Ground Fault Leakage Detector Model 2620 CHAPTER 3 SPECIFICATIONS 3 1 Reference Conditions Ambient temperature 23 C 3K Relative humidity 20 to 75 RH Position of the conductor Centered in the jaws Current frequency and form Sinusoidal 50 60Hz 0 2Hz distortion lt 1 Superimposed DC current No DC current Continuous magnetic field Earth field lt 40 A m Alternating magnetic field No external alternating magnetic field Proximity of external conductors None Measuring device s impedance 2 10MO 100pF 3 2 Electrical 4A Range Nominal Current 4AAC Measurement Range 0 5mA to AAAC Output Signal 1mVAc mAAc 4A Range 0 5 to 10mA 10 to 100mA 100mA to 4A Accuracy 3 of R 1mV 0 5 of R40 5mV 0 5 of R 0 5mV Phase Shift lt 15 lt 10 400A Range Nominal Current AOOAAC Measurement Range 0 5A to 400AAc Output Signal 1mVAc AAc 400A Range 0 5 to 10A 10 to 100A 100 to 400A Accuracy 0 5 of R 0 5mV 0 35 of R 4 0 5mV 0 35 of R 1mV Phase Shift lt 1 lt 0 6 1 800 561 8187 www led com information itm com Ground Fault Leakage Detector Model 2620 7 Overloads Ip limit current permanent 400 AC RMS e Peak current lt 1000A e Permissible transient di dt lt 30A us e Conductor temperature lt 70 C with a maximum peak of 90 C Lo
22. rent of that magnitude Different cables in the installation may not have equivalent capacitance and resistance These cables provide for high current and of course we apply a high current Therefore we may have a capacitive influence which corresponds to 45mA Q Must the conductors be centered within the jaws A You should avoid placing the conductors close against the magnetic circuit near the gaps and should group the conductors as much as possible Best results are obtained while centering the conductor You must also ensure that the jaw mating surface are perfectly clean and that nothing prevents them from closing tightly Q Is it possible when checking cables which run parallel yet supply the same load to clamp the detector over each cable separately A When there are parallel cables the measurement is valid only if the detector includes the cables together In fact if you take each one sepa rately it is highly probable that the distribution of current in the parallel cables is not even These differences can be caused by the fact that the 1 800 561 8187 www GED com information itm com Ground Fault Leakage Detector Model 2620 15 Q I have detected faults of 400mMA and 250mA on branch circuits being supplied by the feeder But clamping onto the incoming feeder resulted in an indication of 350mA Can you explain why 400mA 250mA 350mA A The detector measures residual current in other words the vectorial sum of
23. t C it detects zero therefore the fault is not in the oven At points B and D the detector picks up 1A showing that the fault is in the motor If it gets worse the leakage current will increase and the circuit breaker will trip This motor should be disconnected immediately and repaired GND RESIDUAL CURRENT 1A GND Figure 2 In a three phase installation the principle is the same But here it is necessary to pass all active conductors through the detector including the neutral if one is used If this is done properly the detector output will be zero if there is no current leaking to ground If it detects something other than zero there is a ground fault that should be repaired 42 Equipment Troubleshooting To locate a fault quickly begin your troubleshooting at the incoming low voltage distribution header Successively check each feeder If the Model 2620 detects a ground fault follow the feeder downstream branch by branch to the equipment with the problem It is useful to take measurements periodically to create a history of the quality of the insulation This is good preventive maintenance which could prove valuable later If you detect a fault current that is very low initially but increases from dav to dav this means that electrical failure is immi 1 800 561 8187 www GED com information itm com snutaown Ground Fault Leakage Detector Model 2620 11 For best results center the conductors within the clamp jaws
24. the currents If you have a 400mA fault and a 250mA fault on the same phase you have every chance of finding 650mA But if you have two faults on different phases they add as vectors actually in a very theo retical case we could even find zero Q The Model 2620 detects faults caused by insulation failures How does detecting faults with the detector differ from information result ing from megohmmeter insulation tests A The Model 2620 will detect electrical faults while the equipment is still in operation This offers two distinct advantages First it is not necessary to shut the equipment down eliminating costly down time and second you may detect faults that would not be evident under non energized conditions Q Would it be possible to clamp the Model 2620 directly around the grounding detector A Yes in some instances it may be possible to detect fault current on a specific motor if there is a dedicated grounding path However if several devices are sharing a common ground it should be noted that the fault may be occurring on any one or multiple of the devices 1 800 561 8187 www GED com information itm com 16 Ground Fault Leakage Detector Model 2620 CHAPTER 5 ARTIFICIAL NEUTRAL A Warning A The measurement of leakage current is done specifically with a clamp designed for this purpose The Artificial Neutral must be connected to a known low resistance ground If fault finding exceeds 15 minutes remove t
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