Clamp-On Ground Resistance Testers Models 3710 and 3730
Contents
1. NEUTRAL BUS gt p GROUNDBUS e e WH BK 120 VAC e Bare 0 SERVICE PANEL GROUND ELECTRODE v Figure 28 Ground Resistance Tester Models 3710 3730 27 Phone Pedestal Provide sufficient room for the Model 3710 3730 jaws which must be able to close easily around the conductor Fig 29 The jaws can be placed around the ground rod itself Note If not enough room is available for this task refer to Fig 30 and continue with this example The clamp must be placed so that the jaws are in an electrical path from the sheath bond s or ground bar to the ground rod s as the circuit provides Select the current range Clamp onto the ground conductor and measure the ground current The maximum current range is 30 Amps If the ground current exceeds 5 Amps ground resistance measure ments are not possible Do not proceed further with the measurement Remove the clamp on tester from the circuit noting the location for maintenance and continue to the next test location After noting the ground current select the ground resistance range O and measure the resistance directly The reading you measure with the 3710 3730 indicates the resistance of not just the rod but also the con nection to the sheath ground and all bonding connections between the sheath bond and the rod A high reading indicates one or more of the following2. Generally 0 7 Q R 19j indicates that you are on a closed loop In Fig 26 the ground rod is located outside the enclosure Clamp at the indicated measuring point to obtain the cor rect reading If more Enclosure Figure26 than one rod exists at different corners of the enclosure it is neces sary to determine how they are connected to Underground properly measure the Service ground resistance Ground Rods Ground Resistance T ester Models 3710 3730 25 Transmission Towers Observe all safety requirements Dangerously high voltage may be present Locate the ground conductor at the base of the tower Many different configurations exist Care should be taken when searching for the ground conductor Fig 27 shows a single leg mounted on a concrete pad with an external ground conductor The point at which you clamp the instrument should be above all splices and connections which allow for multiple rods butt wraps or butt plates Note Current flowing to ground may be high Central Office Locations The main ground con ductor from a ground window or a ground plane is usually the Support location to clamp the tester Due to the wiring practices within A L the central office Ground Rod Figure 27 there are many loca tions at which you can look at the water pipe or counterpoise from with in the building An effective location is usually at the ground
3. A Poor ground rod B Open ground conductor C High resistance bonds on the rod or splices on the conductor Also look for bad connections on the ground bar to the sheath s Note This same test can be done using the TIP instead of the sheath ground However keep in mind that this is intended to be grounded only back at the central office 28 Ground Resistance T ester Models 3710 3730 Pedestal KC 3 Ground Bar 4 Sheath Connection He e 34 PS Ground level KO Figure 29 Phone 1 Remove ground bar Pedestal connection to pedestal rod Et 2 Extend pedestal rod lead to the ground bar using a temporary jumper Ground Bar Sheath Connection Ground level Ground rod Figure 30 Above Telephone Space Select the current range A Clamp onto the ground wire and measure the current Fig 31 The maximum current range is 30 Amps If the ground current exceeds 5 Amps resistance measurements are not possible Do not proceed further with the measurement Remove the clamp on tester from the circuit noting the location for attention and continue to the next test location Ground Resistance Tester Models 3710 3730 29 After noting the current select the ground resistance range and measure the resistance directly The reading you measure with the 3710 3730 indicates the bonding connections between the Telephone groun
4. 33 Can the clamp on method used for substation grid resistance testing A It depends It can be used as long as the instrument can be clamped onto a point on the grounding system at a common point where it ties to the system neutral Testing a grid must be treated as if it were a single electrode Often clamping on to points within the grid system will yield a closed loop reading Q How does clamp on ground testing compare with the standard Fall Of Potential test A Empirical testing has validated that when performed correctly both methods will provide accurate and repeatable readings for ground elec trode resistance Q How large a conductor can the jaw accommodate A The inner diameter of the jaw is 1 25 and can accommodate cables up to 1000 MCM Battery Replacement Procedure The Clamp On Ground Resistance Testers are powered by a single 9 volt battery The battery replacement indicator will display continuously when battery replacement is required Recommended replacement type is Alkaline IEC 6LF22 6LR61 or NEDA 16044 Ni Cad batteries may also be used To change the bat tery refer to figure 15 page 17 and follow this procedure 1 The instrument must be OFF and disconnected from any conductor 2 Place the meter face down and remove the two Phillips screws on the back of the instrument 3 Remove back cover by pulling it down and away from the instrument 4 Lift the battery away from the case and
5. 99 separate values may be logged for either resistance current A or a com bination thereof At the 99th value display number will blink indicating that memory is full Memory recall register Displays the numbered value being recalled from memory 1 99 Note Models 3710 and 3730 share the same LCD and display all segments at power up Functions not available on the 3710 are displayed at power up 12 Ground Resistance T ester Models 3710 3730 Function Controls Model 3710 and 3730 share common functions On Off A Auto off Buzzer disable Hold Even though the Model 3710 is shown in the examples for these functions the controls will respond identically for the Model 3730 On Off The ON OFF push button when pushed actuates power on or power off with an audible control tone Upon initial power up the instrument will be in the Ohms function and will go to OL until clamped on When the ON push button is pushed and held down after three seconds the instrument will beep and provide a self test featuring a full function dis play Fig 4 followed by status indications for a Status of remaining battery life battery symbol blinks 0 100 Fig 5 b Number of stored values in memory MEM blinks 0 99 Model 3730 only Release the ON OFF push button to initialize the instrument A light chirping sound may be heard in the mode This is a normal condition generated by the instruments power management
6. The important factor is that it be a multiple electrode system Q Does the grounding electrode have to be disconnected and isolated as is required when using the Fall Of Potential test with auxiliary electrodes A No Actually the electrode must be connected to the system to provide the path for test signal injection as well as to provide the background impedance necessary as the reference Additionally if the tested rod is poorly bonded to the ground connector a high reading will be present Does this mean 1 am not able to test an independent electrode A No however as soon as the connection is made to a multiple elec trode system usually provided by the connection to the system neutral you can clamp on and make a measurement Q Must the instrument be clamped directly on the electrode A No the instrument will provide valid measurement results when clamped on to the electrode or the conductor leading to the grounding electrode The reading through the conductor will also verify not only the grounding electrode resistance but connections of the ground wire to the rest of the system Q Does the system under test have to be energized or de energized to perform the test A We are measuring the grounding network The only requirements are that ground connections be made to the system under test and that the voltage to ground at the tested point not exceed the instrument rating Ground Resistance Tester Models 3710 3730
7. also have both types acting as a ground In these cases it is necessary to make the mea HA Building Wall gt surements between the ser Pole mounted vice neutral and both grounded points Service Service Meter Box Ground Level mo Figure 23 ods Pole mounted Transformer Service Meter f Water Pipe Figure 24 24 Ground Resistance T ester Models 3710 3730 Pad Mounted Transformer Observe all safety requirements High voltage may be present Locate and number all rods usually only a single rod is present If the ground rods are inside the enclosure refer to Fig 25 and if they are outside the enclosure refer to Fig 26 If a single rod is found within the enclosure the measurement should be taken on the con ductor just before the bond on the ground rod Often more than one ground conductor Seem e is tied to this clamp oncentric looping back to the Underground service Neutral enclosure or neutral Enclosure Open Door Open Door Buss In many cases the Figure25 ais rod s best reading can be obtained by clamping the instrument onto the ground rod itself below the point when the ground conductors are attached to the rod so that you are measuring the ground circuit Care must be taken to find the conductor with only one return path to the neutral
8. audibly and visually indicate if the reading is beyond an input set point The user may also have the Alarm initiated above or below the set point This Alarm feature permits quick field checks where only pass or fail readings will suffice The Memory function logs up to 99 measurements Ohms or Amperes This enables the user to conduct field surveys and to retrieve and analyze the readings at a later time The alarm settings and stored memory information are saved when the ground tester is turned off Product Construction The Models 3710 and 3730 body cases are built of Lexan for rugged use The probe heads are encapsulated in a double walled Lexan shell Ground Resistance T ester Models 3710 3730 5 for extra strength and are reinforced at the body interfaces for enhanced field reliability Overall construction and mechanical design ratings such as drop test shock and vibration weatherproofing against water projections or dust meet or exceed IEC International Electrotechnical Commission standards The products have also been designed to meet IEC 1010 UL 1244 CSA and GS safety approvals Jaw Design The probe head or jaw is a key component in the measurement and overall product performance Considerable research and development were dedicated to ensuring its performance reliability and versatility The large jaw has an inner opening diameter of 1 25 32 mm double its predecessors diameter while retaining the same
9. buss in the power room or near the backup generator Concrete Pad a By measuring current and resistance at several points and comparing the readings you will be able to identify neutral loops utility grounds and central office grounds The test is effective and accurate when the ground window is connected to the utility ground at only one point 26 Ground Resistance T ester Models 3710 3730 Service Panel If we clamp on the grounding electrode conductor in Fig 28 the multi grounded system required to complete the circuit may be from different sources These sources may include the following Electric Neutral Phone CATV and Water The Electric Utility Neutral should be the principle conductor of the low impedance signal return path required to test the resistance of this ground electrode with the Model 3710 3730 This can be verified by removing other ground connections noting if any changes appear in the readings If by removing one of these signal return paths a much higher reading is noted it could mean that the primary signal return path the Electric Neutral is defective uns Note For safety B NEUTRAL reasons do not re ttt move any ground Sat V source without first 7 a de energizing the PHONE service panel CATV
10. calibration loop Cat 1223 01 4 Ground Resistance T ester Models 3710 3730 Description Outline The ground resistance tester Models 3710 and 3730 measure ground rod and small grid resistance through any season without the use of auxiliary ground rods Clamp on ground resistance testers are used in multi grounded systems without disconnecting the ground under test The Models 3710 and 3730 simply clamp around the ground conductor or rod and measure the resistance to ground By performing measurements on intact ground systems the user also verifies the quality of the grounding connections and bonds Resistance and continuity of grounding loops around pads and buildings may also be measured Both models include a current measurement function The probe s high sensitivity enables measurement of leakage current flowing to ground or circulating in ground loops down to 1 mA and neutral currents to 30 A rms This feature provides additional information which is becoming vital as distribution ground networks carry higher levels of noise and harmonics which affect power quality Both models offer battery life information at power up and Auto Off for power management Additional features are also displayed on the large LCD to ensure precise measurements The Buzzer and Auto Off features may be disabled from the push buttons at any time The Model 3730 offers an Alarm function and a Memory logging func tion In the Alarm mode the probe will
11. disconnect the battery 5 Connect the new battery and position the leads so that they won t get pinched when the cover is replaced 34 Ground Resistance T ester Models 3710 3730 6 Replace the back cover noting that it slips beneath the hold down lip and fits securely into position 7 Install and tighten screws Typical battery life is approximately 8 hours of use or about 1000 separate 30 second measurements Troubleshooting Symptom Indication Recommended Action Instrument will not turn ON Low Battery Replacement required Continuous audible tone Alarm setpoint tripped Deactivate Alarm or Change Setpoint Trigger mode Display is erratic Foreign matter in jaws Clean jaw mating surfaces Function controls inoperative Hold button on Turn HOLD off Light pulsing audible beep Normal operation Battery power management feature Ground Resistance Tester Models 3710 3730 35 Repair and Calibration To guarantee that your instrument complies with the factory specifica tions we recommend that the Models 3710 amp 3730 be submitted to our factory service center at one year intervals for recalibration or as required by other standards For instrument repair and or calibration please call our factory toll free at 800 945 AEMC 800 945 2362 CHAUVIN ARNOUX Inc d b a AEMC Instruments 15 Faraday Drive Dover NH 03820 USA Tel 800 954 2362 603 749 6434 Fax 603 742 2346 Or contact your authorized
12. instrument around ener gized electrical equipment Never attempt to use the instrument to twist or pry the ground electrode or ground wire away from the equipment being grounded Open and close the clamp on jaws slowly ensuring proper alignment AEMC Instruments considers the use of rubber gloves to be an excellent safety practice even if the equipment is properly oper ated and correctly grounded Ground Resistance T ester Models 3710 3730 3 Receiving Your Shipment Upon receiving your shipment be sure that the contents are consistent with the packing list Notify your distributor of any missing items If the equipment 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 Packaging The Clamp On Ground Resistance Testers Model 3710 Cat 1221 01 and Model 3730 Cat 1221 02 are shipped with a hard carrying case one 9 V battery not installed an instruction manual with warranty registration and a calibration loop The manual warranty card and cal ibration loop are located behind the egg crate foam on the inside of the carrying case cover Government Orders The Clamp On Ground Resistance Tester Model 3710 Cat 1221 01 has been issued a National Stock Number Orders for the Model 3710 should reference NSN 6625 01 377 8030 Accessories One multiple
13. of 25 and we were to clamp around any electrode in the system the measured value would be 25 Q in series with the equiva lent parallel resistance or 0 25 The displayed value would be 25 2 Q instrument resolution to 0 1 VA 25 Q 0 252 25 2 Q In most field applications the number of electrodes that make up multi grounded system would be higher therefore the equivalent parallel resistance is negligible with respect to the rod under test Ground Resistance T ester Models 3710 3730 21 Figure 20 ral a g a Figure21 Ground Resistance T ester Models 3710 3730 22 Field Applications Pole Ground Rods Remove any molding covering the ground conductor and provide suffi cient room for the jaws of the clamp on The jaws must be able to close easily around the conductor The jaws can be placed around the ground rod itself Note The instrument must be placed so that the jaws close around an electrical path from the system neutral or ground wire to the ground rod or rods as the circuit provides Select the current range A Clamp onto the ground conductor and mea sure the ground current The maximum range is 30 00 A Trms However if the ground current exceeds 5 A or noise exceeds 50 V ground resis tance measurements are not possible Do not proceed further with the measurement Remove the instrument from the circuit noting the location for m
14. overall jaw thickness permitting use on tight ground conductors on poles and in manholes The large opening accommodates not only ground rods but larger ground conductors up to 1000 MCM typically found in telecom munication or railroad applications The inner jaw is composed of two independent and individually shielded magnetic cores permitting the injection of a test signal and accurate return signal measurement without noise interference or cross talk common to separate probe instruments Thorough mechanical design including small winglets ensures repetitive jaw alignment for accuracy and prevents undesirable insertions into the jaw spring assembly Body Design The ergonomic body design permits one handed operation The guard provides additional strength and prevents the hand from slipping or coming into contact with conductors under test The Lexan body con struction provides strength The LCD lens cover may be easily replaced if scratched The sealed push buttons directly access all test functions and are easily operated even with gloved hands Lexar is a registered trademark of General Electric Corporation 6 Ground Resistance T ester Models 3710 3730 Electrical Specifications Ground Resistance Measurement Range Range Resolution Accuracy 1 0 to 50 0 Q 0 10 1 596 0 1 50 0 to 100 0 Q 0 52 2 0 0 5 Autoranging 100 to 200 2 19 3 0 1 1 0 to 1200 Q 200 to 400 Q 50 6 0 5 400 t
15. setting the alarm trigger 1 The instrument must be OFF and disconnected from any conductor 2 Place the meter face down and remove the two phillips screws on the back of the instrument 3 Remove the back cover by pulling down and away from the instrument 4 To set the alarm to trigger above a setpoint slide the alarm setpoint switch to the right To set the alarm to trigger below a setpoint slide the alarm setpoint switch to the left 5 Replace the back cover while ensuring that it slips beneath the hold down lip and fits securely into posi tion Use caution not to pinch the battery leads 6 Install and tighten screws Alarm Setpoint Switch Right Alarm above the setpoint Left Alarm below the setpoint Battery Compartment Figure 15 18 Ground Resistance T ester Models 3710 3730 To activate the Memory feature press the A and ON buttons together at power AEM C Model 3730 GROUND TESTER up Fig 16 MEM will be displayed The Memory feature allows the user to log into memory 1 to 99 measured values including OL Measured values can now be logged for both resistance and amps A by pushing the MEM button during measurement and during HOLD A long beep indicates the measurement was stored After the 99th value is entered MEM 99 will blink indicating memory is now full Measurements may still be made but no longer logged St
16. 0 Q 04 4 7 Lever Opens or closes jaws 8 AL Activates deactivates 8 6 5 the Alarm function access the value of the Alarm setpoint in program mode 9 MEM Stores the reading into memory reads Memory Recall MR values and clears the memory in recall mode 10 Ground Resistance T ester Models 3710 3730 Digital Display Features NOISE mA A 1 ST NOISE Li CI CI CI mA DOGG XD D a To O 10 moo ICI Figure3 Displayed when the beeper is active To turn the beeper On Off push ON amp Q together at power up The beeper is active when displayed Displayed when the HOLD function is activated This function locks the present displayed value During HOLD A and Alarm functions are deactivated The Memory function may still be used Indicates that the jaws of the instrument are not properly closed The Open Jaw indication is present only in the Mode Check for foreign matter in the jaw mating surface In the Q function this symbol indicates the presence of exces sive stray noise in the ground electrode under test This symbol will be present if noise signals reach an amplitude of approx 5 A or 50 V Resistance measurement values are no longer valid The beeper is also activated Displayed when measured resistance is below 1 This may indicate that grounding electrode you are clamped onto is continuous with itself t
17. Clamp On Ground Resistance Testers Models 3710 and 3730 USER MANUAL INSTRUMENTS Chauvin Arnoux Inc d b a AEMC Instruments 99 MAN 100061 Rev 05 03 98 Clamp On Ground Resistance Testers Models 3710 and 3730 USER MANUAL Owner s Record The serial number for the Model 3710 or Model 3730 is located inside the battery compartment of the instrument Please record this number and purchase date for your records CLAMP ON GROUND RESISTANCE TESTER MODEL 3710 CATALOG 7221 01 5 _ PURCHASE DATE 72222 DISTRIBUTOR ___ CLAMP ON GROUND RESISTANCE TESTER MODEL 3730 CATALOG 1221 02 SERIAL PURCHASE DATE oo DISTRIBUTOR 99 MAN 100061 6 5th Revision AEMC Instruments Printed 03 98 by Chauvin Arnoux Inc Table of Contents WY API tU ee Ut ie veut 3 Receiving Your Shipment 4 Packaging x spe T ute e eM PD exer RS 4 Government 5 4 DSSCIIDUOME cp PT 5 Electrical Specifications 7 Mechanical Specifications 7 Safety Specifications 8 Model 3710 Controls RE ened Dive cias 9 Model 3730 Controls 10 Digital Display 11 Additional Features of the 3730 12 F nctio
18. aintenance and continue to the next test location After noting the ground current select the ground resistance range and measure the resistance directly The reading you measure with the clamp on tester indicates not just the resistance of the rod but of the connection to the system neutral and all bonding connections between the neutral and the rod Note that in Fig 22 there is both a butt plate and a ground rod In this type of circuit it is necessary to place the instrument 711 above the bond so that both grounds are includ ed in the test For future reference note the date ohms reading current reading and pole number Replace any molding you Figure22 may have removed from the conductor Grounding X conductor D e S 22 EE Utility Ground Ground level pole Butt plate zx ii Ground Resistance T ester Models 3710 3730 23 Note A high reading or OL indicates one or more of the following A Poor ground rod B Open ground conductor C High resistance bonds on the rod or splices on the conductor watch for buried split butts clamps and hammer on connections Service Entrance or Meter Follow the same procedure as for Pole Ground Rods Notice that Fig 24 shows multiple ground rods and in Fig 23 the ground rods have been replaced with a water pipe ground You may
19. atures of the Model 3710 and 3730 AEM C Clamp on Ground iNsrruueu s Resistance Tester Model 3710 3730 Operating Reference ON OFF ON OFF Measure ground resistance Q Measure AC current mA HOLD Freeze hold the display Toggle the buzzer 2 on off Toggle auto power on off Model 3730 Additional Features A Turn alarm AL on off MEM Store the reading in memory Toggle memory display on off Program alarm mode Use lt q gt to adjust Short beep On off memory recall MR Long beep 6s Clear memory CLR A Down Up gt Figure 32 Ground Resistance Tester Models 3710 3730 31 Calibration Check Loop The multiple calibration loop is now replaced by a single point 25 Q loop Fig 33 It is provided to perform a quick check of the instruments Check the clamp on ground resistance tester by clamping around the loop the 3710 or 3730 should read between 24 2 and 25 8 Value is for ambient temperature between 68 and 78 F Value may differ a few counts under or above this temperature AEMC CALIBRATION LOOP 250 Figure 33 32 Ground Resistance T ester Models 3710 3730 Commonly Asked Questions for Clamp on Ground Resistance M easurements Q Can the Clamp on method be used effectively on high tension tow ers despite the distance or spacing between them A Yes Extended distances will not adversely effect the measurement results
20. d and the Power company ground One of the following two scenarios should be observed A If OL or a high resistance reading is displayed this would indicate no bond has been established or a poor connection exists between the Telephone and Power grounds B If R 16 and or a very low reading is displayed then the bond between these two grounds has been verified Staples EEE 4 dE Ground wire doubled under ground clamp Figure31 General Measurement Notes A reading of OL is most likely a cable which is not connected to the ground at both ends It may be there is no ground rod at all or that there is no path back to the system neutral A reading which is 0 7 Q B 6 generally indicates that the cable where you are clamped is continuous with itself You may have located a ground loop which can usually be confirmed by comparatively high current readings also obtained when readings are taken at multiple locations A good low resistance ground may also have very high AC current flowing depending upon the type of equipment being grounded 30 Ground Resistance T ester Models 3710 3730 Operating Reference Included with the Model 3710 and 3730 you will find an operating refer ence card like the one shown here This card summarizes all the fe
21. distributor Estimates for repairs normal recalibration and calibration traceable to N I S T are available upon request Overseas customers must receive written authorization before returning any instrument Technical and Sales Assistance If you are experiencing any technical problems or require any assis tance with the proper use or application of this instrument please call our technical hotline CHAUVIN ARNOUX Inc d b a AEMC Instruments 200 Foxborough Blvd Foxborough MA 02035 USA Tel 800 343 1391 508 698 2115 Fax 508 698 2118 WWW aemc com 36 Ground Resistance T ester Models 3710 3730 Limited Warranty These Ground Resistance Testers Models 3710 amp 3730 are warrantied to the owner for a period of 1 year from the date of original purchase against defects in manufacture This limited warranty is given by AEMC Instruments not by the distributor from whom it was purchased This warranty is void if the Ground Resistance Testers Models 3710 amp 3730 have been tampered with abused or if the defect is related to ser vice not performed by AEMC Instruments What AEMC Instruments Will Do If a malfunction occurs within the 1 year period you may return the Ground Resistance Testers Models 3710 amp 3730 to us for repair or replacement free of charge provided we have your REGISTRATION CARD on file AEMC Instruments will at its option repair or replace the faulty material Note If a card is not on fi
22. he instrument is measuring a metallic loop and not the ground electrode resistance In this situation electrode resistance measurements may not be valid Current measurement mode Ground resistance measurement mode Ground Resistance Tester Models 3710 3730 11 ITA ILILI Indicates the Auto Off feature is deactivated and the instrument stays on permanently until turned off by the user With no symbol displayed after 5 minutes of non use the instrument will automatically shut itself off The Auto Off feature is turned On Off by pressing Hold at power up Display flashes this symbol 1 second during a low battery condition Measurements are still possible When this symbol is displayed continuously measurements are no longer possible Battery replacement is necessary Indicates the approximate percentage of useful battery life remaining 0 100 This function is displayed only upon initial power up when the ON push button is held down for more than 3 seconds The overload symbol will illuminate when the measurement reading is beyond the limits of the instrument Resistance gt 1200Q Current gt 30 00 A rms The beeper is activated in current overload Additional Features of the Model 3730 m 55 Indicates that an alarm set point is set in memory Alarm set points may be set from 1 to 1990 Arrows indicate whether the measured value is above or below alarm setpoint Memory function is activated Ninety nine
23. igure 12 16 Ground Resistance Tester Models 3710 3730 Turn the Alarm on off by pressing the AL button The alarm feature pro vides a continuous audible warning Model 3730 GROUND TESTER when beeper is active and visual indications when a setpoint has been reached Fig 13 14 e g alarm indi cation when ground electrode resis tance is above the NEC limit of 25 If the alarm is not triggered only will be displayed indicating that the alarm is active Figure 13 Programming the Alarm Setpoint To program the alarm setpoint push ON and AL together at power up The alarm setpoint value will blink To program the proper setpoint value 1 to 199 use the curser arrows 4 down gt up AEM C Model 3730 When the setpoint is reached turn GROUND TESTER the instrument off This will put the setpoint into memory Turn the instrument back on you may need to press AL to activate the alarm fea ture Note The alarm setpoint is preset at 25 The alarm will be triggered when the setpoint is exceeded Figure 14 The user has the option of having the alarm triggered when a reading is below the programmed setpoint This is accomplished with an internal switch and outlined in the following section Ground Resistance Tester Models 3710 3730 17 Changing the Alarm Trigger The Model 3730 alarm may be set to trigger above or below a setpoint Follow the procedure below for
24. istance T ester Models 3710 3730 Resistance The Q function provides resistance measurements from 1 0 to 12000 in six autoranges Fig 9 Range Resolution 1 0 to 50 0 Q 0 1 Q 50 0 to 100 0 O 0 5 Q 100 to 200 Q 10 200 to 400 Q 400 to 600 Q 10 Q 600 to 12000 50 Q Figure9 Upon initial power on the function is chosen by default The Models 3710 and 3730 will track AEMC Model 3710 down to 0 7 and indicate R 10 GROUND TESTER below 1 Q Fig 10 Below 0 7 Q the display stays locked on 0 7 Accuracy is not defined below 1 Measurements below 1 typically indicate the ground tester is clamped onto a closed loop and that the signal is not through the ground under test AEMC Model 3710 GROUND TESTER Figure 11 Ground Resistance T ester Models 3710 3730 flowing Figure 10 If the resistance readings are above 1200 OL will be displayed on the LCD Fig 11 This may indicate high ground resistance but may also be caused by a disconnected or poorly bonded ground 15 Current Press A to enter the current function True RMS current measurements are possible up to 30 00 A Fig 12 Above 30 Arms OL will be displayed and the test must be discontinued The beeper is also activated during OL Range Resolution 1 to 300 mA 1mA 0 300 to 3 000 A 0 001 A 1 mA 3 00 A to 30 00 A 0 01 A 10 mA AEM C Model 3710 GROUND TESTER F
25. le we will require a dated proof of purchase as well as your REGISTRATION CARD accompanied by the defective material What You Must Do First obtain a return authorization by phone or by fax from AEMC Instruments then return the Ground Resistance Testers Models 3710 amp 3730 indicating place and date of purchase with a writ ten explanation of the reason for return Return material postage pre paid to Chauvin Arnoux Inc d b a AEMC Instruments Service Department 15 Faraday Drive Dover NH 03820 USA Tel 800 945 2362 603 749 6434 Fax 603 742 2346 Caution To protect against in transit loss we recommend that you insure your returned material For full warranty coverage please read the Warranty Card which is affixed to the Warranty Registration Card Please keep the Warranty Card with your records
26. n Gontrols 7 d eu Yu Le bed 13 Programming the Alarm Setpoint 17 Changing the Alarm Trigger 18 MEMON ERR enar buc See OER EG 19 Memory Recall 200444 eser lerra ka Need mex Ei News 19 Clear Memory 19 Function Access Summary 20 Programming 5 20 Principle of Operation 21 Field Applications 0 0 0 BIA 23 Operating Reference 31 Calibration Check Loop 32 Commonly Asked Questions 33 Battery Replacement 34 Table of Contents cont Troubleshooting seien 35 Repair and Calibration 36 Technical and Sales Assistance 36 Limited Warranty Inside back cover Warning These safety warnings are provided to ensure the safety of per sonnel and the proper operation of the instrument The instrument must not be operated beyond its specified oper ating range Safety is the responsibility of the operator All metal objects or wires connected to the electrical system should be assumed to be lethal until tested Grounding systems are no exception Use extreme caution when using the
27. o 600 Q 10 0 1096 10 600 to 12000 50 Q Approx 2596 Ground or Leakage Current Autoranging 1 to 300 mA 1 2 5 2 1 to 30 00 Arms 0 300 A to 3 000 A 0 001 A 2 5 2 mA 3 00 A to 30 00 A 0 01A 2 5 20 mA Reference conditions 23 C 3K 50 RH 10 battery at 8 V 0 2V external magnetic field lt 40 A m external electrical field lt 1 V m conductor centered loop resistance noninductive Accuracy of reading Resistance Measurement Frequency 1689 Hz Resistance Overload OL displayed above 1200 Q Current Measurement Frequency 47 to 800 Hz Current Overload OL displayed above 30 A rms MECHANICAL SPECIFICATIONS Dimensions 9 25 x 3 94 x 2 17 235 x 100 x 55 mm Weight 2 2 lbs 1 kg Case Material Lexan 920A UL94V2 Ground Resistance T ester Models 3710 3730 7 Jaw Cover Material Lexan 500R with 1096 fiberglass charge UL94VO LCD Cover Material Lexan 920A UL94V1 Color Gray body red jaws Jaw Window Diameter 1 25 32 mm Jaw Opening 1 38 35 mm Operating Temperature 10 to 55 C Operating Humidity 0 to 90 RH 9 10 to 40 75 RH 9 55 Storage Temperature 40 to 70 Power Supply 9 V alkaline IEC 6LF22 NEDA 1604A Battery Life typical 8 hours or approximately 1000 measurements of 30 seconds LCD 3 3 4 digit 1 73 x 1 10 44 x 28 mm US Design Patent 362 639 SAFETY SPECIFICATIONS UL CSA approval
28. ored values are retained when the instrument is turned off Figure 16 Pressing the A and ON buttons again at power up will de activate the Memory feature Memory Recall To recall memory values push ON and AEM Model 3730 MEM together at power up MR will be dis GROUND TESTER played with the memory number Fig 17 Memorized value will be displayed To select stored values use the cursor arrows 4 down gt up For rapid access of memory recall values press the cursor push button continuously Turn the instrument off to exit the Memory Recall mode Figure 17 Clear Memory To clear the memory push ON amp MEM together at power up and hold them down After a three second interval the clear message will be displayed Fig 18 along with four repetitive beeps and a fifth long tone The memory is now cleared Fig 19 Once cleared releasing the ON amp MEM buttons returns the instrument to Resistance measurement mode Ground Resistance Tester Models 3710 3730 19 AEMC Model 3730 GROUND TESTER Figure18 Function Access Summary AEM Model 3730 GROUND TESTER Figure19 Push Button s Function Setting Function Used Saved Power Down On Off ON OFF Q Function Q Default Setting A Function A No Alarm Function Q AL Yes Display Hold HOLD No Auto Off On Off ON HOLD No Beeper On Off ON Q No 3710 Yes 3730 Programming Summary Push Buttons F
29. s pending IEC 1010 1 Double Insulation Environmental IP30 359 Group III Vibration Test IEC 68 2 6 Shock Test IEC 68 2 27 Drop Test 1m IEC 68 2 32 Dielectric Test 2500 V AC Working Voltage 150 V Cat III Pollution Degree 2 300 V Cat III Pollution Degree 1 Max A Overload 100 A continuous 200 A 5s 50 60 Hz OL displayed above 30 A rms Calibration Cycle Calibration once a year is recommended 8 Ground Resistance T ester Models 3710 3730 Model 3710 Controls 1 Head Assembly Consists of 4 ON OFF Power ON or OFF two individually shielded activates display self test at magnetic cores power up 2 Hold Freezes last measured 5 Resistance measurement value on the display 6 A Current measurement 3 Display 3000 count LCD 7 Lever Opens or closes jaws function indicators Ground Resistance T ester Models 3710 3730 Model 3730 Controls 1 Head Assembly Consists of two individually shielded magnetic cores 2 Hold Freezes last mea sured value on the display 3 Display 3000 count LCD function indicators 4 ON OFF Power ON or OFF activates display self test at power up 5 Resistance Measurement gt Increment the Alarm set point increment Memory position in program mode AEM Model 3730 GROUND TESTER 08 5 9158 6 A Current Measurement a Decrement the Alarm setpoint decrement the E Memory in program mode 9 0
30. system AEMC Model 3710 GROUND TESTER SE NOISE cin CH OI CI CI mA LLL B Ng Oo moo 9 55 AEMC Model 3710 GROUND TESTER 1111 ET NOISE FOO POCHI mA BBB5B8 amp I Figure4 Figure5 Ground Resistance T ester Models 3710 3730 13 Auto Off The instrument will shut off automatically after five minutes of non use The instrument will issue a short beep 15 seconds prior to shutting down and the LCD flashes once per second The Auto Off may be disabled by turning on the meter while holding AEM C Model 3710 GROUND TESTER down the HOLD push button The indicator will appear on the display to indicate the Auto Off feature has been disabled Fig 6 Hold The HOLD push button freezes the last measured value onto the display When the HOLD function is enabled is displayed on the LCD Fig 7 When the HOLD function is enabled other control functions are dis abled except the memory function To exit HOLD press the HOLD push button and normal operation is resumed Note When HOLD is pressed dur ing power up the auto off feature is disabled and g is displayed on the LCD See Auto Off Figure 6 Figure 7 AEM C Model 3710 GROUND TESTER Beeper Disable To disable the beeper press the ON Q together at power up The essa indicator will disappear from the LCD Fig 8 Figure8 14 Ground Res
31. unction Setting Function Used Saved Power Down Memory On Off ON A Yes Memory Recall MR ON MEM lt 2 sec No Clear Memory ON MEM gt 6 sec No Program Alarm ON AL No Setpoint 20 Ground Resistance Tester Models 3710 3730 Principle of Operation Typically grounded distribution system may be simulated by the basic circuit shown in Fig 20 or an equivalent circuit shown in Fig 21 If volt age V is applied to any measured grounding electrode Rx through a special transformer current 1 flows through the circuit thereby establishing the following equation Rx i where usually Ry ca HE Bi Rn Therefore V I Rx is established If is detected and measured with V kept constant the measured grounding electrode resistance Rx can be obtained A signal is fed to a special transformer via a power amplifier from a 1 689 kHz constant voltage oscillator The resulting current is then sensed by a detection CT An active filter is used to dampen earth current at commercial frequency and high frequency noise Example If we clamp around any grounding electrode in a multi grounded System the measured value of the electrode under test will be the resis tance of that particular rod in series with the equivalent parallel resistance value that the rest of the multi grounded system represents If we had an electrical system that had 101 grounding electrodes and each had a resistance value
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