User Manual - PMC Rentals
Contents
1. SNOEN IN PEN SOET IFAT BEAN orwors n swe VA KE CINMIITMRES SEVEN ccr ONENTS GF anoun OP E pu vier IRPATICN POT EM AX Fc nnarm x Figure 6 Diagram of Megger ACV DC High Pot Testers 230425 230425 1 S ritme z FACS OED ZAE Tt ruhr ORE NG BCAMOOFTZ OM EI SA ALE SLIP DN OH 1 sz BAL BIT IEA MALT VERMINAL oa MENDTES 26706 METER VES BARE A DE IGH EHOMM ACTIVATED FR MY P MEL 1 22 COMPONENTS ANT AILT NOT USS AIS PIT ma Ps CA 8 W IDOLE 22772 IN DO POSITION 1 AVTM23 4J Rev 2 Dec 2010 Megger AVTM23 4J Rev 2 Dec 2010 782. sse 18 AVTM23 4J Rev 2 Dec 2010 5 0 DESCRIPTION iie tesnzscue festinet tide tetto iei eroi 19 Control and Connector Identification 19 6 0 OPERNA TION aa 25 25 26 Preliminary Routine Qy 27 Shutdown BIrocedute u u tenete oe tte 27 Operating 28 Operating Procedure 29 7 0 APPLICATION NOTES u u u n odie 35 Properties of Insulation 35 Leakage 35 37 Dielectric Voltage Withstand Test Characteristics 38 aca 38 Instructions for Setting Leakage Sensitivity Control 42 42 IbIGMI e 43 Dielectric Withstand Testing of Low VAC Appliances 45 8 0 MAINTENANCE ettet rettet RSS 47 Routine Maintenance detecte 47 Mechanical Inspection Exterior 47 Mechanical Inspection Interior 48 Electrical Inspection sicisscisssicsssscscssasiesessseactseste dessssasdsaeisbeatasdessesssievedetnses 49 GaliDtati i 57 Setup taste 57 Calibration Procedure 58 AVTM23
3. FOH Forrett He H 1111 43 Tre al SLTIOAOTIM m amp o 3 m 5 2 o Typical Output Characteristics of the Megger AC DC High Pot Tester in the DC Mode Figure 4 4J Rev 2 Dec 2010 AVTM23 1 4 Megger Instructions for Setting the Leakage Sensitivity Control AC Testing Set the LEAKAGE SENSITIVITY control R77 according to the capacitance of the item under test if known Follow the guidelines given below Capacitance of Unknown If the capacitance of the item under test is unknown always set the LEAKAGE SENSITIVITY control R77 at the most sensitive setting Rotate the control knob counterclockwise toward the 0 3 mA position This insures the best test results and maximum protection for both the operator and the item under test Low Capacitance Items The capacitance of most items is well below 1000 pF which implies a leakage current less than 0 3 mA when tested at 1000 to 1200 volts In such cases the Tester can be used with the LEAKAGE SENSITIVITY control R77 at the 0 3 mA position AVTM23 4J Rev 2 Dec 2010 42 Application Notes Medium to High Capacitance Items If an item has a capacitance greater than 1000 pF and its capacitance voltage point falls below the maximum output line in Figure 3 it can be tested with the LEAKAGE SENSITIVITY control R77 at some intermediate position between 0 3 mA and 12 mA Exc
4. Press the CONT pushbutton S2 Observe the following conditions The HV ON lamp DS3 should light If not see Section 9 The kilovoltmeter M1 should read zero Press the HV OFF pushbutton 53 The HV ON lamp DS3 should go out 4 Leakage Sensitivity Test a b d Set the power switch CB1 to the OFF position Connect the high voltage test probe assembly W1 to the AC OUTPUT receptacle J8 Connect the 1 0 resistor user supplied between the leads of the high voltage test probe assembly W1 Insulate the resistor test probe assembly for at least 4000 volts locate the assembly to prevent accidental contact with persons Set the LEAKAGE SENSITIVITY control R77 to 0 3 mA Rotate the VOLTAGE CONTROL T3 to the ZERO START RESET position AVTM23 4J Rev 2 Dec 2010 52 Maintenance g Set the power switch to the ON position The switch should light WARNING Do not touch or permit anyone else to touch the resistor test probe assembly h Press the CONT pushbutton 52 The HV ON lamp DS3 should light Slowly rotate the VOLTAGE CONTROL T3 clockwise while observing the kilovoltmeter M1 indication When the kilovoltmeter M1 shows between 100 and 400 volts the FAILURE lamp DS2 should light and the audible alarm should sound j Rotate the VOLTAGE CONTROL T3 to the ZERO START RESET position k Repeat steps 1 through 10 usi
5. Failure This indicator lights and an audible alarm sounds when a breakdown occurs or an excessive leakage current is drawn by the item under test AVTM23 4J Rev 2 Dec 2010 19 Megger 053 On This indicator lights when high voltage is available to the Output Receptacle J8 and the high voltage test probe receptacle J9 DS5 Tester Grounded This indicator lights when the Tester is connected to a correctly wired power supply NOTE Since the current through this lamp is limited to 0 5 mA 120V operation this lamp will not be as bright as the otber indicators 8 AC Output Receptacle This receptacle accepts the high voltage test probe assembly W1 for AC high voltage testing 9 DC Output Receptacle This receptacle accepts the high voltage test probe assembly W1 for DC high voltage testing AVTM23 4J Rev 2 Dec 2010 20 Descriptions M1 Kilovoltmeter This meter shows the voltage being applied to the item under test 7 Input Inlet This inlet accepts the input power cord W3 R77 Leakage Sensitivity This variable potentiometer allows the leakage current trip level to be set between 0 3 mA and 12 mA 51 One Sec This pushbutton initiates the one second high voltage test NOTE This test is recommended for AC testing only since DC testing usually involves a high initial charging current which may cause failure signal AVTM23 4J
6. lighting of the FAILURE lamp DS2 a sudden voltage drop or an erratic kilovoltmeter M1 reading 10 When the Tester detects a failure the audible alarm sounds the FAILURE lamp DS2 lights and high voltage is switched off AVTM23 4J Rev 2 Dec 2010 32 Operation To turn off the failure signals and continue testing return the VOLTAGE CONTROL 13 to the ZERO START RESET position or press the RESET pushbutton S4 AVTM23 4J Rev 2 Dec 2010 33 Megger AVTM23 4J Rev 2 Dec 2010 34 7 0 APPLICATION NOTES Properties of Insulation Leakage Current All electrical insulating structures when subjected to voltage conduct some current When alternating voltage is applied this current is made up of two components one due to conduction through or across the surface of the insulator the resistive and one due to the capacitance of the structure the capacitive Both of these components are undesirable and by design are kept very small in new equipment Nevertheless some current of both types always leaks around or through any insulator hence the name leakage current Under some definitions only the resistive component is called leakage but this manual follows current practice by also including the capacitive Leakage current of both resistive and capacitive components increases with voltage and generally with the size of equipment Capacitive current in particular is high for item
7. operated electrical appliances AVTM23 4J Rev 2 Dec 2010 2 0 SAFETY PRECAUTIONS SAFETY IS THE RESPONSIBILITY OF THE USER La seguridad es la responsabilidad del operador Equipment Safety Precautions WARNING The voltages and currents produced by the tester can cause harmful or fatal electric shock to the user or bystander For your protection follow all Safety Procedures given in this manual The Megger AC DC High Pot Tester has been designed with careful attention to safety Megger has conducted formal safety reviews of the initial equipment design and all subsequent changes This procedure followed for all new instruments covers areas in addition to those included in the American National Standards Institute ANSI standard Because hazards exist with all electrical test equipment proper procedures and precautions must be observed by the user when operating this instrument The basic safety AVTM23 4J Rev 2 Dec 2010 Megger procedures to be followed when operating this equipment are given in this section Additional safety instructions are provided in other sections as appropriate In addition the instrument has been marked with precautionary warnings Safety notations used in this manual and on the instrument indicate various degrees of hazard to personnel equipment The notations are listed below with brief explanations of how they are applied CAUTION Cautions alert you t
8. R11 R23 Resistor 6810 1 RN55D 12398 71 R12 R13 R19 Resistor 100 1 4W 5 4501 91 R30 R31 R38 R39 R45 R46 R50 R60 R65 R14 Resistor 10 3W 1 6 10646 17 kV R15 R90 Resistor 37 4 kO 1 12398 19 RN55D R16 Resistor 20 1 RN55D 12398 1 R17 Resistor 11 1 RN55D 12398 176 R18 Potentiometer 10 12340 10 R20 Resistor 1 1 RN55D 12398 16 R21 Resistor 19 60 1 RN55D 12398 191 R22 Resistor 2000 1 RN55D 12398 4 R24 Resistor 56 1 4W 5 4501 90 Carbon Composition R25 Resistor 6800 1 4W 5 4501 66 Carbon Composition R27 R36 Resistor 5 1 1 4W 5 4501 540 AVTM23 4J Rev 2 Dec 2010 70 Replaceable Parts List Schematic Description Part No Symbol R29 R49 Resistor 470 kQ 1 4W 5 4501 513 Carbon Composition R32 Resistor 360 kQ 1 2W 5 4501 536 Carbon Composition R34 R35 R40 Resistor 510kQ 1 4W 5 4501 509 R41 R43 R67 Carbon Composition R28 R44 R47 Resistor 200 1 4W 5 4501 525 Carbon Composition R51 Resistor 392 kO 1 12398 192 RN55D R52 Resistor 2 MO 1 RN55D 12398 193 R53 Resistor 330 1 4W 5 4501 510 Carbon Composition R55 Resistor 1500 1 4W 5 4501 545 Carbon Composition R56 R57 Resistor 1 1 4W 5 4501 51 Carbon Composition R58 Resistor 1 MO 196 RN55D 12398 81 R59 R61 Resistor 1
9. Mode Selection Four pushbuttons provide the following selections One Second Test Momentary actuation of the ONE SEC pushbutton turns on high voltage for a period of from 1 second minimum to 1 3 seconds maximum unless a failure occurs This test is recommended for AC testing only since DC testing usually involves a high initial charging current which may cause a failure signal To begin initial testing or after a failure the RESET pushbutton must be actuated or the VOLTAGE CONTROL returned to the ZERO START RESET position Once the Tester is reset the One Second Test can be repeated as many times as desired Continuous Test Momentary actuation of the CONT pushbutton turns on high voltage until the HV OFF pushbutton is actuated or a failure occurs Each time high voltage is turned off or after a failure the RESET pushbutton must be actuated or the VOLTAGE CONTROL returned to the ZERO START RESET position HV Off Momentary actuation of the HV OFF pushbutton turns off high voltage AVTM23 4J Rev 2 Dec 2010 15 Megger Reset Momentary actuation of the RESET pushbutton stops failure signals and allows further testing NOTE The RESET pushbutton is also a zero start override When the output voltage has been preset and the HV OFF pushbutton has been depressed high voltage can be turned on to the preset value by depressing the RESET button then the CONT or ONE SEC test pushbutton Failure
10. Rev 2 Dec 2010 21 Megger S2 Cont This pushbutton is provided for high voltage testing for any desired length of time When this button is used high voltage remains on until the HV OFF pushbutton is depressed or a failure occurs S3 HV Off This pushbutton switches off high voltage It may be used at any time S4 Reset This pushbutton stops failure signals and allows further testing Voltage Control This autotransformer serves as voltage control reset and zeto start W1 High Voltage Test Probe Assembly not shown This lead assembly plugs into either the AC or DC output receptacle J8 J9 for high voltage testing AVTM23 4J Rev 2 Dec 2010 22 Descriptions W2 Input Power Cord not shown This cord plugs into the input inlet 7 It is provided with an outboard end appropriate to the input voltage requirement 120V 240V Output Receptacle Slide This slide connects voltmeter MI to either the AC or the DC circuit AVTM23 4J Rev 2 Dec 2010 23 Megger J8 BELOW SLIDE J9 P7 DS5 R77 M1 DANGER w LEAKAGE SENSITIVIT 2 3 KLOVOLTS OUTPUT voc CAUTION D mld VOLTAGE OUTPUT RECEPTACLE SLIDE Figure 2 Controls and Connectors AVTM23 4J Rev 2 Dec 2010 24 6 0 OPERATION SAFETY PRECAUTIONS Follow all safety precautions given in Section 2 0 of this manual Test Area Wh
11. Rev 2 Dec 2010 48 Maintenance WARNING Hazardous voltages may be retained in the C 30 capacitor located on the AC DC metering circuits assembly board even after the tester has been turned off Do not handle the tester until this capacitor has been grounded with a 1K ohm resistor across the cap and short circuited for at least one minute d Turn the panel assembly right side up and place on a clean dry surface 2 Clean any accumulated dust from the interior of the case and the panel assembly Visually inspect all components and leads for defects Repair any defects found Remove the resistive load from capacitor C 30 9x Bo 8 Reinstall the panel assembly in its case and replace the mounting screws Electrical Inspection Perform the electrical inspection only after both mechanical inspections have been completed Before performing this inspection read the entire procedure given below as well as Sections 2 5 and 6 Follow all safety precautions AVTM23 4J Rev 2 Dec 2010 49 Megger If the Tester does not function exactly as it should during any of the following tests refer to Section 9 0 Troubleshooting Guide 1 Setup a With the power switch CB1 off connect the input power cord W2 to the Tester INPUT inlet P7 then plug the input power cord W2 into grounded outlet b Verify that the TESTER GROUNDED lamp 055 is lit WARNING If the tester grounded
12. a ratio of greater than 1 the item cannot be tested If the capacitance and resistance of the item under test are unknown the setting of the LEAKAGE SENSITIVITY control R77 can be determined by trial and error during the testing of an identical known good item Always set the control to the most sensitive setting as described above for AC testing AVTM23 4J Rev 2 Dec 2010 44 Application Notes Dielectric Withstand Testing of Low VAC Appliances Most 120 VAC tools and appliances are frequently tested at 2 times working voltage 1000 volts 1240 V Some standards however call for other values of dielectric withstand voltage Such standards are issued by many different authorities The latest issue of the standard which applies in each particular case should be consulted A few standard authorities are listed below in alphabetical order American National Standards Institute ANSI 25 W 4391 St 4 Floor New York NY 10036 USA Canadian Standards Association CSA 178 Rexdale Boulevard Rexdale Ontario Canada M9W1R3 International Electrotechnical Commission 3 Rue de Varembe CH 1221 Geneva Switzerland 20 Copies of IEC standards can be obtained from ANSI Underwriters Laboratories Inc UL 333 Pfingsten Road Northbrook IL 60062 USA AVTM23 4J Rev 2 Dec 2010 45 Megger AVTM23 4J Rev 2 Dec 2010 46 8 0 MAINTENANCE Routine Maintenance Certain routine maintenance procedures
13. are necessary to insure safe and correct operation of the Tester These are described below Always make all of these inspections after repairs to the Tester and at regularly scheduled intervals Make the inspections at least once a year more often if the set is in heavy use Mechanical Inspection Exterior 1 Case Note that hinges and case lock function properly Check for cracks in the case or lid Inspect the condition of the handle 2 Clean the case panel test probe assembly and input power cord 3 Panel Note that all knobs are secure on their shafts that all controls operate smoothly without binding and all mounting screws are tight AVTM23 4J Rev 2 Dec 2010 47 Megger 4 Test Probe Assembly Check for cracks in the insulation Note that the alligator clips and boots are complete Check and tighten screw connections at clips 5 Input Power Cord Check for cracks in the insulation Check cord plugs for cracked housings or broken pins 6 Mechanically set the kilovoltmeter to zero 7 Repair any defects found Mechanical Inspection Interior WARNING AN The tester must be turned off and disconnected from the power supply before it is removed from its case 1 remove the panel assembly from the case a Remove and set aside the four panel screws b Carefully turn the case so that the panel assembly faces down c Slide the case up off the panel assembly AVTM23 4J
14. high voltage test probe assembly W1 Set the voltage to 4 kV and use the DC CAL pot R97 to correct for any discrepancy between the standard DC voltmeter and the Tester kilovoltmeter M1 11 Unplug the input power cord W2 reinstall the panel assembly into its case and replace the mounting screws AVTM23 4J Rev 2 Dec 2010 60 9 0 TROUBLESHOOTING GUIDE Repairs Megger Instruments maintains a complete instrument repair service Should this instrument ever require repair we recommend that it be returned to the factory for repair by our instrument specialists When instruments are returned for repair either in or out of warranty they should be shipped Prepaid and Insured and marked for the attention of the Repair Service Manager Before troubleshooting is attempted the Tester should be completely checked for proper operation as described in Section 8 0 Maintenance NOTE The Tester develops dangerous interior voltages and employs printed circuit card construction therefore repairs must be made only by qualified persons Figure 5 shows some of the internal components of the Tester and gives their schematic reference numbers Section 10 0 Replaceable Parts List identifies all AVTM23 4J Rev 2 Dec 2010 61 Megger components used in the Tester and gives the Megger Part Numbers For safety it is recommended that only Megger replacement parts be used when making repairs to the Tester Refe
15. incoming power line This circuit lights a white neon lamp as soon as the Tester is connected to a correctly wired power supply The grounded circuit of the Tester is interlocked with the dielectric voltage withstand test so that high voltage cannot be applied if either of the following common faults exist a Ground wire open b and NEUTRAL wires interchanged 120V operation Dielectric Voltage Withstand A high voltage transformer supplies test voltage to two panel jack assemblies A slide selects the desired panel jack assembly either AC DC and automatically connects the proper metering circuit A high voltage test probe assembly plugs into the open panel jack assembly for output voltmeter indicates the test voltage Visual and audible alarms signal when the total leakage current exceeds an adjustable preset value or when arcing occurs AVTM23 4J Rev 2 Dec 2010 18 5 0 DESCRIPTION Control and Connector Identification The locations of controls and connectors and their schematic reference numbers are shown in Figure 2 Their functions ate described below CB1 Input Circuit Breaker Power Switch This circuit breaker controls the power input to the Tester It disconnects the power circuit if more than 1 ampere is drawn by the Tester DS1 Power This indicator is an integral part of the Input Circuit Breaker Power Switch It lights when power is available to the Tester DS2
16. received against the packing list Notify Megger Norristown PA 19403 of any shortage of materials Examine the instrument for damage received in transit If any damage is found file a claim with the carrier at once and notify Megger or its nearest authorized sales representative Be sure to provide a detailed description of the damages observed Your Megger instrument has been thoroughly tested and inspected to rigid specifications before being shipped and is ready for use when set up as indicated in Section 6 0 Operation AVTM23 4J Rev 2 Dec 2010 Megger AVTM23 4J Rev 2 Dec 2010 10 4 0 SPECIFICATIONS Physical Characteristics Dimensions Weight 8 3 8 D x 9 W x 8 1 8 H 213 x 229 x 206 mm 13 5 Ibs 6 1 kg Environmental Recommendations Operating Temperature Storage Temperature Humidity Climate 25 F to 104 F 4 C to 40 C 22 F to 131 F 30 C to 55 C Operation and storage limits 5 to 95 RH Operation prohibited in direct rain or snow AVTM23 4J Rev 2 Dec 2010 11 Megger Input 230425 230425 1 Input Protection 120 volts 10 50 60 Hz single phase with ground Connection to the Tester is made via a removable 7 1 2 ft power cord with a molded PVC grounding plug PH 290B NEMA configuration 5 I5P on one end and a molded PVC grounding connector SPH 386 on the other 240 volts 10 0 5A 50 60 Hz single phase
17. with ground Connection to the Tester is made via a removable 6 1 2 ft power cord with a molded PVC grounding plug PH 44 NEMA configuration 6 15P on one end and a molded PVC grounding connector SPH 386 on the other 2 pole 1 Amp 250V rocker handle circuit breaker AVTM23 4J Rev 2 Dec 2010 12 Specifications Output AC Mode 0 4000 VAC continuously adjustable Maximum short 12 6 mA electronic limitation circuit current Maximum load 0 008 uF 60 Hz 0 010 uF 50 Hz at maximum voltage Maximum capacitive loads are proportionally higher at reduced output voltages See Figure 3 in Section 7 0 Application Notes DC Mode 0 5000 VDC continuously adjustable negative polarity with respect to ground Maximum 12 6 mA electronic limitation current Maximum 0 4 RMS per mA at full voltage no ripple capacitive load NOTE Ripple will be greatly reduced with a capacitive load For complete loading capability see Figure 4 in Section 7 0 Application Notes AVTM23 4J Rev 2 Dec 2010 13 Megger Metering Average reading RMS calibrated Style 3 1 2 zero left analog meter with high torque ruggedized movement Range 0 5000 V NOTE AC readings stop at 4 kV Accuracy 2 Full Scale Controls Voltage Control Voltage is controlled manually by means of an adjustable autotransformer with zero start interlock AVTM23 4J Rev 2 Dec 2010 14 Specifications
18. 00 kO 1 12398 27 RN55D R62 Resistor 5 62 kO 1 12398 7 RN55D AVTM23 4J Rev 2 Dec 2010 71 Megger Schematic Description Part No Symbol R63 Resistor 4 02 kO 1 12398 131 RN55D R64 Resistor 100 kO 1W 5 4501 371 Carbon Composition R67 Resistor 4 7 1 4W 5 4501 53 Carbon Composition R69 Resistor 2 1 4W 5 4501 511 Carbon Composition R70 R71 R72 Resistor 22 kQ 1 4W 5 4501 554 Carbon Composition R75 Resistor 10 2W 5 4501 423 Carbon Composition R77 Potentiometer 50 17135 7 R91 Potentiometer 20 kO 23986 5 R92 Resistor 15 11 RN55D 12398 15 R93 R94 Resistor 8 MO 5W 190 10 10646 45 kV R96 Resistor 5 36 196 12398 52 RN55D R97 Potentiometer 5 kO 23986 4 S1 54 Pushbutton Switch 17137 S6 Line Selector Switch 18620 AVTM23 4J Rev 2 Dec 2010 72 Replaceable Parts List Schematic Description Part No Symbol 7 58 Microswitch 25727 T1 Transformer Primary 25141 115 230V Secondary 16V 0 4 T2 High Voltage Transformer 25140 T3 Autotransformer 120V Tester 6408 2 T3 Autotransformer 240V Tester 17787 U1 Integrated Circuit Schmidt 25045 8 Trigger Quad Nand Gate 4093 U2 U3 Integrated Circuit Quad Op 25045 27 Amp LM324 U4 U5 Integrated Circuit Opto 2
19. 17142 DS5 TESTER GROUNDED 4499 8 Neon White 250V 1 3W E1 E13 Male Quick Disconnect Tab 17029 1 E5 E6 Insulated Standoff 23063 E9 E10 E11 2 Pin Male Strip 22931 2 F1 Subminiature Fuse 1 16A 25421 1 J8 J9 High voltage Receptacle 23978 2 K1 Relay Coil 12 VDC 25114 Contact 250 VAC 3A LS1 Alarm AT 03 25198 M1 Kilovoltmeter 5 kV Full Scale 19937 9 AVTM23 4J Rev 2 Dec 2010 68 Replaceable Parts List Schematic Description Part No Symbol P7 Recessed Power Inlet 250V 18305 6A Q1 Q5 Transistor 2N3904 11638 62 R26 R33 Resistor 1 MO 1 4w 5 4501 508 R37 R42 R48 Carbon Composition R66 R1 Resistor 24 3 KO 1 4W 11 12398 144 R2 Resistor 169 1 4W 1 12398 92 R3 Resistor 33 1 2W 5 4501 186 Carbon Composition R4 Resistor 2200 2W 5 4501 407 Carbon Composition R5 R54 Resistor 47 1 4W 590 4501 514 Carbon Composition R6 Resistor 15 1 4W 5 4501 71 Carbon Composition R7 R68 R76 Resistor 8200 1 4W 5 4501 69 Carbon Composition R8 Resistor 4700 1 4W 5 4501 575 Carbon Composition Resistor 4300 1 4W 5 4501 576 Carbon Composition R10 Resistor 10 1 4W 5 4501 506 AVTM23 4J Rev 2 Dec 2010 69 Megger Carbon Composition Schematic Description Part No Symbol Carbon Composition
20. 4J Rev 2 Dec 2010 9 0 TROUBLESHOOTING GUIDE een 61 61 10 0 REPLACEABLE PARTS 67 11 0 WARRANTY amp REPAIR 75 VEN eo asa 75 sans heh ee iN tected eich melds ch an 75 AVTM23 4J Rev 2 Dec 2010 iii List of Figures Figute1 Megger AC DC High v Figute 2 Controls and Connectots 24 Figure 3 Typical Output Characteristics of the Megger AC DC High Pot Tester in the AC Mode 40 Figure 4 Typical Output Characteristics of the Megger AC DC High Pot Tester in the DC Mode 41 Figute 5 Internal View of Tester a isole es 63 Figure 6 Schematic Diagram of Megger ACV DC High Pot Testers 230425 amp 230425 1 75 AVTM23 4J Rev 2 Dec 2010 Figure 1 gt AC DC High Pot Tester Catalog 230425 AVTM23 4J Rev 2 Dec 2010 DANGER The high voltages produced by this equipment can be extremely dangerous Any equipment to be tested must first be disconnected from its power supply All personnel must be kept clear of connections and bare parts of equipment where high voltages may be present SAFETY IS THE RESPONSIBILITY OF THE USER All users of this equipment should read and understand this manual before operating the equipment and
21. 5257 Isolator IL 250 VR1 Voltage Regulator LM340AT 23691 5 W1 High Voltage Test Probe 25149 Assembly W2 Input Power Cord 120V 17032 Tester W2 Input Power Cord 240V 17032 2 Tester Zero Start Contact Mounted on 23202 T3 Output Receptacle Slide 25722 AVTM23 4J Rev 2 Dec 2010 73 Megger Schematic Description Part No Symbol Knob for T3 4690 25 Knob for R77 25146 Case Assembly 10998 Lid Assembly 22389 4 Instruction Card 26112 NOTE The following components on PC Board Assembly 1 P N 23138 are not used CR3 E9 E10 R14 R15 R16 R17 R18 R19 Part of PC Board Assembly Al P N 25138 Part of PC Board Assembly A2 P N 25134 Part of PC Board Assembly P N 25729 AVTM23 4J Rev 2 Dec 2010 74 11 0 WARRANTY 8 REPAIR Warranty All products supplied by Megger are warranted against all defects in material and workmanship for a period of one year following shipment Our liability is specifically limited to replacing or repairing at our option defective equipment Equipment returned to the factory for repair will be shipped Prepaid and Insured The warranty does not include batteries lamps or tubes where the original manufacturer s warranty shall apply WE MAKE NO OTHER WARRANTY The warranty is void in the event of abuse or failure by the customer to perform specified maintenance as indicated in this man
22. AGE CONTROL T3 to the ZERO START RESET position 4 Set the LEAKAGE SENSITIVITY control R77 to 0 3 mA AVTM23 4J Rev 2 Dec 2010 58 Maintenance 5 Set the power switch CB1 to the ON position The switch should light WARNING While the tester is energized do not touch or permit anyone else to touch any exposed parts 6 Press the CONT pushbutton S2 The HV ON lamp DS3 should light 7 Slowly rotate the VOLTAGE CONTROL 13 clockwise while observing the standard voltmeter Set the voltage to 3 kV The Tester kilovoltmeter M1 should also read 3 kV 2 of full scale If there is discrepancy use the insulated screwdriver to rotate the AC CAL pot R91 until the standard voltmeter and the Tester kilovoltmeter MI show the same voltage NOTE The calibration pots are located on the AC DC metering circuits assembly board 43 8 Check several other voltages and be sure that all are within tolerance AVTM23 4J Rev 2 Dec 2010 59 Megger 9 After the kilovoltmeter M1 is calibrated and checked rotate the VOLTAGE CONTROL T3 to the ZERO START RESET position press the HV OFF pushbutton S3 and set the power switch CB1 to the OFF position 10 Repeat steps 1 through 9 with the high voltage test probe assembly W1 connected to the DC OUTPUT receptacle J9 and the standard DC voltmeter user supplied connected between the alligator clips of the
23. AVTM23 4J Rev 2 Dec 2010 Instruction Manual AC DC High Pot Testers Catalog No 230425 amp 230425 1 Megger Valley Forge Corporate Center 2621 Van Buren Avenue Notristown PA 19403 2329 U S A 610 676 8500 WW HIGQgeT COM High Pot Testers Catalog No 230425 amp 230425 1 Copyright 2010 by Megger All rights reserved The information presented in this manual is believed to be adequate for the intended use of the product If the product or its individual instruments are used for purposes other than those specified herein confirmation of their validity and suitability must be obtained from Megger Refer to the warranty information below Specifications are subject to change without notice WARRANTY Products supplied by Megger are warranted against defects in material and workmanship for a period of one year following shipment Our liability is specifically limited to replacing or repairing at our option defective equipment Equipment returned to the factory for repair must be shipped prepaid and insured Contact your MEGGER representative for instructions and a return authorization RA number Please indicate all pertinent information including problem symptoms Also specify the serial number and the catalog number of the unit This warranty does not include batteries lamps or other expendable items where the original manufacturer s warranty shall apply We make no other warranty The warranty is void
24. Detection and Automatic Shutdown The failure detection circuit indicates a failure by audible and visual alarms and switches off high voltage within 50 ms whenever arcing occurs or the total leakage current exceeds a preset value The leakage current trip level for AC output is adjustable between 0 32 mA 5 to 12 3 mA 5 by means of the LEAKAGE SENSITIVITY control knob For DC output is adjustable between 0 41 mA 5 to 10 1 mA 5 by means of the LEAKAGE SENSITIVITY control knob AVTM23 4J Rev 2 Dec 2010 16 Specifications Indicators Tester Grounded HV On Power Failure Audible Alarm Accessories Catalog No 230425 2 Test Connections Lights when the Tester is connected to a properly wired supply Lights when the high voltage output is energized Integral to power switch Lights when power is available to the Tester Lights when a breakdown occurs or an excessive leakage current is drawn by the item under test Sounds when the failure lamp is lit Removable high voltage test probe assembly 4 feet long with retractile test tips The item to be tested is connected by means of the alligator clips on the 4 ft long removable high voltage test probe assembly AVTM23 4J Rev 2 Dec 2010 17 Megger Tests Performed Tester Grounded A low current less than 0 5 mA 120 V operation line monitoring circuit is connected between the HOT side and the ground side of the
25. T pushbutton S4 does not turn off failure signals Defective IC U1 U3 Defective transistor Q1 Q2 Defective opto isolator US Defective IC U1 U2 U3 Defective RESET pushbutton S4 Defective ZERO START RESET contact Defective transistor Q2 AVTM23 4J Rev 2 Dec 2010 66 10 0 REPLACEABLE PARTS LIST Pole 250V 1A Schematic Description Part No Symbol C1 C11 C20 Capacitor 22 uF 50V 17127 13 C2 Capacitor 1000 uF 25V 23908 1 C3 Capacitor 01 uF 1000V 9865 25 C4 Capacitor 47 uF 20V 17132 3 C5 C13 C14 Capacitor 471 100V 19836 8 C6 C8 C17 Capacitor 1000 pF 100V 17127 1 C9 Capacitor 470 pF 1000V 7950 24 C10 Capacitor 047 uF 100V 17127 2 C12 Capacitor 01 uF 100V 17127 9 C15 Capacitor 01 uF 630V 19836 10 C16 Capacitor 001 uF 1000V 7950 12 C19 C23 Capacitor 1 uF 50V 17127 7 C18 C21 C22 Capacitor 4700 pF 100V 17127 4 C30 Capacitor 25 uF 6000V 25731 1 CB1 Circuit Breaker 2 23964 AVTM23 4J Rev 2 Dec 2010 67 Megger Schematic Description Part No Symbol CR1 CR3 Bridge Rectifier VM18 22921 CR2 CR6 Diode 1 4148 11637 40 CR27 CR35 CR40 CR41 CR42 Diode H463 5 19173 CR4 CR5 Transzorb 1 5 KE20CA 17040 5 DS1 Neon Part of CB1 062 FAILURE LED Yellow 17142 1 DS3 HV ON LED Red
26. akage current or an arcing fault The leakage current trip level is adjustable between 0 3 mA and 12 mA by the LEAKAGE SENSITIVITY control R77 The Tester indicates a failure by the audible alarm and the FAILURE lamp DS2 and it switches off high voltage within 50 ms AVTM23 4J Rev 2 Dec 2010 38 Application Notes Occasionally the operator may detect a visible or audible discharge or erratic voltmeter indication without an accompanying failure signal from the Tester These represent borderline cases in which the discharge energy remains small and does not build up to a full breakdown If such indications are observed repeatedly during a test petiod they should be considered signs of failure If a single snap or pop occurs and is not repeated it may be due to a stray projection or dirt which has burned off in which case the item under test may be acceptable Such weak pops seldom occur at higher test voltages or with high capacitance test items However some complex structures such as relays and transformers may emit a more continuous buzz at high voltage This is a very low energy corona discharge and generally not a sign of insulation failure AVTM23 4J Rev 2 Dec 2010 39 Megger SLTOAOTIM 100 30 20 10 Capacitance in nF Figure 3 Typical Output Characteristics of the Megger AC DC High Pot Tester in the AC Mode AVTM23 4J Rev 2 Dec 2010 40 Application Notes
27. all tests connect the black lead of the high voltage test probe assembly WI first Connect AVTM23 4J Rev 2 Dec 2010 Megger and disconnect the item under test only when high voltage is off 6 Practice test procedures until they become familiar before actually performing tests on equipment 7 Unskilled personnel who use the Tester should be trained in a fixed operating routine for each test setup and supervised by a person who fully understands the operation of the Tester 8 Do not use the Tester or any of its accessories for any purposes other than those described in this manual 9 Never operate the Tester with its case removed dangerous voltages are present within the instrument 10 Have only qualified personnel to repair the Tester Observe all precautions and follow the procedures in Section 9 0 Troubleshooting Guide 11 Maintain the Tester with a regular maintenance program The Tester may be used in a great variety of applications thus it is not possible to foresee every potential hazard that may arise To insure safe use of all equipment involved in a test always treat it carefully It is essential that the user in addition to following all safety instructions in this manual AVTM23 4J Rev 2 Dec 2010 Safety Precautions carefully consider all safety aspects of each test before it is performed For further details on safety practices and precautions for high voltage and high power test
28. ation the VOLTAGE CONTROL 13 clockwise Maintain the selected voltage level for the required time NOTE In a DC test increasing voltage too fast may cause a failure signal 3 To end the test return the VOLTAGE CONTROL T3 to the ZERO START RESET position then press the HV OFF pushbutton S3 The HV ON lamp DS3 will go out WARNING Do not proceed until the kilovoltmeter M1 reads 0 b One Second Test This test is used when several identical items are being tested 1 With the item under test connected set the voltage as for the continuous test A2 above but press the HV OFF pushbutton 53 without returning the VOLTAGE CONTROL 13 to the ZERO START RESET position AVTM23 4J Rev 2 Dec 2010 31 Megger 2 To start a series of one second tests press the RESET pushbutton S4 then press the ONE SEC pushbutton S1 each time a test is to be performed 3 Toend a series of tests return the VOLTAGE CONTROL T3 to the ZERO START RESET position and press the HV OFF pushbutton S3 WARNING Do not proceed until the kilovoltmeter M1 reads 0 8 proceed with additional testing after the HV OFF pushbutton S3 has been pressed retutn the VOLTAGE CONTROL T3 to the ZERO START RESET position or press the RESET pushbutton 54 9 During high voltage testing be alert to failure symptoms such as the sounding of the audible alarm
29. cidental contact with the item under test AVTM23 4J Rev 2 Dec 2010 26 Operation Preliminary Routine Before conducting any test carry out the following routine 1 Review any damage report that has been submitted covering the item to be tested 2 Visually inspect the item to be tested 3 Repair any visible defects before testing Shutdown Procedure To remove high voltage from the item under test set the power switch CB1 to the OFF position or depress and release the HV OFF pushbutton WARNING At the completion of a test when voltage has been switched off do NOT touch the high voltage test probe assembly alligator clips until the voltage shown on the voltmeter is 0 AVTM23 4J Rev 2 Dec 2010 27 Megger Operating Notes High voltage cannot be switched on unless the following interlock conditions are met 1 The TESTER GROUNDED lamp DS5 must be lit 2 The VOLTAGE CONTROL T3 must be in the ZERO START RESET position or the RESET pushbutton S4 must be deptessed AVTM23 4J Rev 2 Dec 2010 28 Operation Operating Procedure To insure safety and accurate test results observe the following procedure when operating the Tester 1 With the power switch CB1 off connect the input power cord W2 to the Tester INPUT inlet P7 then plug the input power cord W2 into a grounded outlet 2 Verify that the TESTER GROUNDED lamp 055 is lit CAUTION If the te
30. erever the Tester is used the test area should be arranged according to the following guidelines 1 Select a dry test area where the operator and all equipment are shielded by suitable barriers from traffic and onlookers Locate the Tester within six feet of a 3 wire grounded outlet and within four feet of the item to be tested Provide a secure insulated mounting area for the item to be tested The insulation must isolate the item to be tested from ground and from any adjacent conductors If the insulation of the mounting area is questionable a rubber electrical grade insulation mat or a suitable piece of acrylic plastic or phenolic can be used as insulation AVTM23 4J Rev 2 Dec 2010 25 Megger 4 Place the item to be tested out of the operator s normal reach Arrange the work area so that the operator can reach the controls of the Tester without any danger of touching the item under test NOTE Rubber gloves or shoes are not required but Megger considers their use an excellent safety practice when handling the item under test Suggestions A sturdy wood workbench is recommended for the test area A simple support may be used to hold the entire Tester in a convenient position with the Tester case secured to the support A space on the workbench may be arranged so that the item to be tested can be clamped securely in place and insulated from ground Barriers are strongly recommended to prevent ac
31. essively High Capacitance Items that Cannot be Tested If the capacitance of an item is so large that its capacitance voltage point falls beyond the maximum output line in Figure 3 it is too large for this Tester to handle This will be clear when attempting to test since even on a good appliance a failure indication will be signaled before the voltage reaches the desired value DC Testing The maximum capacitance of an item that can be tested with AC is approximately 10 nF however the capacitance that can be tested with DC is virtually infinite The upper limit is unlikely to be encountered in practice The maximum output capability of the Tester in the DC mode depends on the combination of the capacitance and resistance of the item under test When the capacitance AVTM23 4J Rev 2 Dec 2010 43 Megger and resistance of the item are known Figure 4 can be used to determine the approximate setting of the LEAKAGE SENSITIVITY control R77 To use Figure 4 first draw a load line representing the resistance of the item As a guide a load line representing a resistance of 1 Megohm has been drawn The ratio of the desired test voltage to the voltage at the point where the load line and the appropriate capacitance curve intersect gives an approximate setting for the LEAKAGE SENSITIVITY control R77 in terms of the full travel of the control knob If the desired test voltage falls to the right of the capacitance curve i e
32. he applied voltage Condition a may lead to b and b usually leads to a continuing breakdown discharge which emits light heat and a crackling sound and carries as much current as the Tester will deliver causing the detection circuit to signal a failure Such a discharge also causes high frequency RF variations in the current which are useful in detection Failure is often caused by defects such as a Dirt on the insulation which causes increased resistive current This may heat the surface and cause a further increase and may lead to a discharge b Cracks or pinholes in insulation which usually lead to a quick breakdown and discharge AVTM23 4J Rev 2 Dec 2010 37 Megger c Shortened air gap due to defective assembly which may cause discharge across the gap An example is a loose strand of wire near the frame d Insulation saturated with moisture This condition may cause a large increase in either component of leakage current Dielectric Voltage Withstand Test Characteristics Output Figure 3 a graph showing output voltage and capacitance illustrates the typical output characteristics of the Tester in the AC mode Figure 4 a graph showing output voltage and output current illustrates the typical output characteristics of the Tester in the DC mode Automatic Failure Detection The Tester is equipped with a failure detection circuit that detects insulation failure in the form of excessive le
33. in the event of abuse failure to follow recommended operating procedures or failure by the customer to perform specific maintenance as indicated in this manual Megger Valley Forge Corporate Center 2621 Van Buren Ave Norristown PA 19403 2329 610 676 8500 Telephone 610 676 8610 Fax WWW IG GET com Table of Contents LOSTINTRODUCTION puma REI ai SE Ea HA Ama 1 2 0 SAFETY PRECAUTIONS 3 Equipment Safety Precautions 3 General Safety Precautions for DC esting 3 0 RECEIVING INSTRUCTIONS eee 9 4 0 SPECIEICA TIONS oett atio 11 41 lt 24 11 Environmental Recommendations 11 n a h ana aa 12 Tapt Protec ON eerte eee tre ta tee terere erae 12 uqha EE S 15 AG Moder esent ee V V RR 13 Modeste top pO dp ie toni enia 13 iade ti t rr teta EEE 14 14 Voltage Control 5 eR e e esi e dais 14 Mode Selections artt crecido iE Uds 15 Failure Detection and Automatic Shutdown 16 Bae ork eo NE et ree RUN 17 ceto edite ie dei p i ace e E EE 17 Test COnie CHGS 17 Tests Perfotmed assusehasp etie tite i RH 18 Testet Grounded 18 Dielectric Voltage Withstand
34. ing refer to IEEE Standard 510 1983 IEEE Recommended Practices for Safety in High Voltage and High Power Testing General Safety Precautions for DC Testing In addition to the basic safety practices described above observe the following precautions when conducting DC tests 1 a b When not in use devices insulated by solid or solid liquid dielectric should be grounded and short circuited with bonding jumpers Capacitive objects should be short circuited as follows If any capacitive object not in use might be within the influence of a DC electric field its exposed high voltage terminal should be grounded Otherwise the DC electric field may induce a voltage in the capacitive object Capacitive objects with a solid dielectric should be short circuited after DC proof testing Otherwise dielectric absorption in the insulation may result in AVTM23 4J Rev 2 Dec 2010 Megger a buildup of voltage on the object The short circuit should remain on the object until the dielectric absorption has dissipated or until the object has been reconnected to a circuit NOTE All capacitive devices should remain short circuited when not in use c Any open circuited capacitive device should be short circuited and grounded before it is touched by personnel AVTM23 4J Rev 2 Dec 2010 3 0 RECEIVING INSTRUCTIONS READ COMPLETELY BEFORE OPERATING When your Megger instrument arrives check the equipment
35. lamp DS5 is not lit do not proceed further Unplug the input power cord W2 and refer to Section 9 0 Troubleshooting Guide 2 Dielectric Voltage Withstand Circuit When the TESTER GROUNDED lamp 055 is lit the dielectric withstand circuit can be checked The following user supplied items are required to conduct the tests a 1 0 MQ 1 4 W resistor b 25 5 W resistor c stopwatch AVTM23 4J Rev 2 Dec 2010 50 Maintenance 3 Zero Start Reset Test a b d 9 h Disconnect the high voltage test probe assembly WI from the Tester Move the output receptacle slide to the far right to cover the DC OUTPUT receptacle J9 This selects the AC output at J8 Rotate the VOLTAGE CONTROL T3 to the first dot above the ZERO START RESET position Press the HV OFF pushbutton S3 Press the CONT pushbutton S2 Observe the following conditions The HV ON lamp 053 should not light If not see Section 9 The kilovoltmeter M1 should read zero Press the RESET pushbutton S4 Press the CONT pushbutton S2 Observe the following conditions The HV ON lamp 053 should light The kilovoltmeter M1 should read a few hundred volts Press the HV OFF pushbutton 53 The HV ON lamp DS3 should go out AVTM23 4J Rev 2 Dec 2010 51 Megger D k Rotate the VOLTAGE CONTROL T3 counterclockwise to the ZERO START RESET position
36. light and the audible alarm should sound 8 Rotate the VOLTAGE CONTROL T3 to the ZERO START RESET position 9 Setthe power switch CB1 to the OFF position NOTE Tf no arc occurs between the test probe alligator clips check that they are spaced approximately 1 16 inch apart and repeat the test 10 Connect the high voltage test probe assembly W1 to the DC OUTPUT receptacle 9 and repeat steps 2 through 9 One Second Test 1 Rotate the VOLTAGE CONTROL 13 to the ZERO START RESET position 2 Disconnect the high voltage test probe assembly W1 from the Tester 3 Setthe power switch CB1 to the ON position The switch should light AVTM23 4J Rev 2 Dec 2010 55 Megger 4 Press the ONE SEC pushbutton 51 The HV ON lamp DS3 should light and stay on for 1 to 1 3 seconds Time the high voltage on period with a stopwatch 5 Set the power switch CB1 to the OFF position If the dielectric withstand circuit functions properly and all other circuit tests have been completed successfully the electrical inspection of the Tester may be considered complete If the dielectric withstand circuit does not function properly refer to Section 9 0 Troubleshooting Guide AVTM23 4J Rev 2 Dec 2010 56 Maintenance Calibration WARNING Because of the dangerous voltages developed during operation of the Tester the following calibration should be carried out only by
37. lly shorted or open HV ON lamp 053 lit Kilovoltmeter M1 reads zero when VOLTAGE CONTROL T3 is rotated toward MAX position Output voltage present Defective kilovoltmeter M1 Defective meter selector microswitches S7 S8 Defective diodes CR40 CR41 One second or continuous test not functioning HV ON lamp DS3 not lit Kilovoltmeter M1 reads zero when VOLTAGE CONTROL T3 is rotated toward MAX position No output voltage TESTER GROUNDED lamp 055 lit IC U1 U4 operating Defective pushbutton S1 for one second test S2 for continuous Defective relay K1 Defective IC U2 U3 Defective transistor Q3 Q4 Q5 Pressing HV OFF pushbutton DS3 does not turn off high Defective pushbutton S3 AVTM23 4J Rev 2 Dec 2010 65 Megger DIELECTRIC WITHSTAND PROBLEM PROBABLE CAUSE voltage Defective IC U2 U3 Defective transistor Q3 Q4 Q5 FAILURE lamp DS2 and audible alarm LS1 do not operate when failure occurs High voltage does not switch off or power switch CB1 trips when failure occurs Defective LEAKAGE SENSITIVITY control R77 Defective IC U1 U2 U3 Defective surge protector CR4 5 FAILURE lamp DS2 and audible alarm LS1 do not operate when failure occurs High voltage switches off when failure occurs Returning VOLTAGE CONTROL T3 to ZERO START RESET position or pressing RESE
38. ng the 25 resistor user supplied instead of the 1 0 MG resistor and with the LEAKAGE SENSITIVITY control R77 set at 12 mA instead of 0 3 mA D Repeat steps a through k with the high voltage test probe assembly W1 connected to the DC OUTPUT receptacle J9 AVTM23 4J Rev 2 Dec 2010 53 Megger m Set the power switch CB1 to the OFF position Disconnect the 25 resistor user supplied Breakdown Sensitivity Test 1 Connect the high voltage test probe assembly W1 to the AC OUTPUT receptacle J8 Place the black and red alligator clip leads of the high voltage test probe assembly W1 approximately 1 16 inch apart They must not touch each other Insulate the test probes for at least 4000 volts and locate the test probe alligator clips to prevent accidental contact with persons Rotate the VOLTAGE CONTROL T3 to the ZERO START RESET position Set the power switch CB1 to the ON position The switch should light WARNING Do not touch or permit anyone else to touch the high voltage test probe alligator clips 6 Press the CONT pushbutton 52 The HV ON lamp 083 should light AVTM23 4J Rev 2 Dec 2010 54 Maintenance 7 Slowly rotate the VOLTAGE CONTROL 13 clockwise while observing the kilovoltmeter M1 indication When there is an arc between the high voltage test probe assembly W1 alligator clips the FAILURE lamp DS2 should
39. o possible damage to equipment WARNING Warnings alert you to conditions that are potentially hazardous to people EARTH GROUND Marking on Instrument DANGEROUS VOLTAGE Marking on Instrument NOTE Notes provide important information AVTM23 4J Rev 2 Dec 2010 Safety Precautions Before using the Tester read and understand this entire instruction manual When operating the Tester carefully follow the testing procedures given in this manual and all applicable safety instructions with special emphasis on those that follow 1 Provide dry test area with operator and all equipment shielded from traffic and onlookers 2 Perform tests on a secure insulated mounting area The insulation must isolate the item to be tested from ground and from any adjacent conductors 3 Place the item under test out of the operator s normal reach Treat the item under test as a shock hazard until it is proven safe by tests performed in accordance with procedures given in this manual 4 Plug in the high voltage test probe assembly WI only when it is being used Handle its clips only by the insulators never touch the clips directh At the completion of a test do not touch the clips until the voltage shown on the voltmeter is zero 0 Unplug the high voltage test probe assembly from the Tester during periods when testing is not actively being done and before leaving the test area 5 For
40. qualified personnel The following items are required for the calibration procedure Setup Insulated sctewdtivet For the AC mode of the Tester a standard AC voltmeter with a range of 4000 volts rms and overall accuracy of 0 5 or better For the DC mode of the Tester a standard DC voltmeter with a range of 5000 volts DC and overall accuracy of 0 5 or better Remove the panel assembly from the Tester case Refer to step I of the Mechanical Inspection Interior procedure for details on removal of the panel assembly AVTM23 4J Rev 2 Dec 2010 57 Megger WARNING The interior of the tester develops dangerous voltages while in operation These voltages AN may be retained even after the unit has been turned off Therefore be sure not to make contact with any of the unit s high voltage components while performing the calibration 2 Set up the Tester according to the setup procedure given for conducting an electrical inspection of the unit Calibration Procedure 1 With the power switch CB1 off connect the high voltage test probe assembly W1 to the AC OUTPUT receptacle J8 and connect the standard AC voltmeter between the alligator clips of the high voltage test assembly W1 2 Insulate the standard voltmeter and all leads from ground and from each other for at least 4000 volts locate the standard voltmeter to prevent accidental contact with persons 3 Rotate the VOLT
41. r to the AC DC High Pot Tester schematic in Section 10 0 Replaceable Parts List in this manual for any required circuit details Contact the factory if major problems are encountered while troubleshooting or making repairs or if assistance is required After repairs have been made always perform a complete inspection of the Tester as detailed in Section 8 0 Maintenance The brief troubleshooting guide that follows identifies some of the problems that may interfere with the proper operation of the Tester AVTM23 4J Rev 2 Dec 2010 62 Troubleshooting Guide w t 12 CHE CERA Figure 5 Internal View of Tester AVTM23 4J Rev 2 Dec 2010 63 Megger TESTER GROUNDED PROBLEM PROBABLE CAUSE 085 not lit TESTER GROUNDED lamp No voltage at service outlet for the Tester Ground wire open or ground contact of service outlet not grounded Hot and neutral wires on service outlet inter changed 120 operation Defective input power cord W2 Defective opto isolator U4 Defective TESTER GROUNDED lamp 055 AVTM23 4J Rev 2 Dec 2010 64 Troubleshooting Guide DIELECTRIC WITHSTAND PROBLEM HV ON lamp 053 lit Kilovoltmeter M1 reads zero when VOLTAGE CONTROL T3 is rotated toward MAX position No output voltage Failure indications may occur PROBABLE CAUSE High voltage circuits interna
42. s that have windings motors transformers or long runs of wire wired control panels etc In good new AVTM23 4J Rev 2 Dec 2010 35 Megger equipment the resistive component is usually much smaller than the capacitive Leakage that occurs during a dielectric voltage withstand test high voltage leakage should not be confused with the leakage that occurs when an appliance is energized at its normal operating voltage and for which limits are specified by various safety standards such as UL This operating leakage is an important safety consideration but it is related only indirectly to high voltage leakage and is normally much smaller Operating leakage cannot be measured by a high pot tester Other Megger instruments are available for measuring this line voltage leakage current The term leakage current is used in this manual to refer to high voltage leakage current The schematic diagram below represents the leakage current paths during a dielectric voltage withstand test In good equipment is usually much less than Ic w quem mimm mm mm tm s TOTAL LEAKAGE CURRENT AVTM23 4J Rev 2 Dec 2010 36 Application Notes Insulation Failure When defective insulation is subjected to a high voltage one of two things happens a Leakage current increases greatly because part of the insulation has become conductive b spark jumps across an air gap which has become too short to withstand t
43. should follow all safety instructions AVTM23 4J Rev 2 Dec 2010 vi 1 0 INTRODUCTION This instruction manual covers the operation and maintenance of the Megger portable AC DC High Pot Tester The input and output characteristics of the tester are indicated by its catalog number as follows 230425 120V 50 60 Hz input 4 AC output 5 kV DC output 230425 1 240V 50 60 Hz input 4 AC output or 5 kV DC output This compact self contained unit is a high voltage low energy source for testing the dielectric strength of electrical insulation Dielectric withstand high pot testing of electrical insulation is a valuable method of detecting assembly flaws such as stray wire strands etc and defects in marginally sound insulation Such conditions can be hazardous to the user and may cause product failure during normal use The Tester has been designed to simplify testing procedures and to minimize hazards to both the operator AVTM23 4J Rev 2 Dec 2010 Megger and the item under test The Tester meets all standards for sensitivity voltage regulation and failure detection currently required by Underwriters Laboratories UL for test equipment used in production line voltage withstand testing of electrical appliances and components The instructions and suggestions provided in this manual anticipate the normal use of the Tester for testing electrical insulation systems on motors transformers and most line
44. ster grounded lamp DS5 is not lit do not proceed any further Unplug the input power cord W2 and refer to Section 9 0 Troubleshooting Guide 3 connect the item under test attach the high voltage test probe assembly W1 to either the AC or DC OUTPUT receptacle J8 or J9 Connect the black lead of the high voltage test probe assembly W1 to the low or ground or return side of the item under test Connect the red lead to the high potential side of the item under test 4 Set the LEAKAGE SENSITIVITY control R77 to the desired setting Refer to SECTION 7 0 AVTM23 4J Rev 2 Dec 2010 29 Megger APPLICATION NOTES for detailed instructions for setting this control 5 Turn the power switch CB1 on The switch should light 6 To enable high voltage testing set the VOLTAGE CONTROL T3 to the ZERO START RESET position or press the RESET pushbutton 54 7 Select the desired test either one second or continuous NOTE The one second test is recommended for AC testing only since the high initial charging current usually present in DC testing may cause a failure signal a CONTINUOUS TEST 1 Press the CONT pushbutton 52 The HV ON lamp DS3 will light WARNING The tester is now capable of producing high voltage 2 While observing the kilovoltmeter M1 indication raise the voltage to the desired level by rotating AVTM23 4J Rev 2 Dec 2010 30 Oper
45. ual or if the instrument is connected to external power sources other than those specified in this manual Repairs Megger maintains complete instrument repair service Should this instrument ever require repairs we recommend it be returned to the factory for repair by our instrument specialists When returning instruments for AVTM23 4J Rev 2 Dec 2010 75 Megger repairs either in or out of warranty they should be shipped Prepaid and Insured and marked for the attention of the Instrument Service manager AVTM23 4J Rev 2 Dec 2010 76 Catalca 53402 Ord nov iA qaraqa f OSA p see eI TEE illana 71 nece eI wE E ER VOETAGE TRANSFORMER PRIMARY VOLTAGE CONTROL CONNECTION DETAILS Levee aus Mea WAV OUTPUT OAM HARI GHBEMUNEN LA LION BEADE ASSY POLE gt DENE ss xc_ccmg AMERY acer MIAZ 3 UNLESS STOPS RE V LESS NOTA AARRED IN meee OTHER mrrrm racrress HOED m PUTE UNLESS HEMM METED ORE 414 gt ALL ARE Tn ee w VOLTAGE
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