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AVTM22-15Ja
Rev B
December 2008
15 kV DC Dielectric
Test Set
Catalog No. 220015 Series
HIGH-VOLTAGE EQUIPMENT
PLEASE READ CAREFULLY BEFORE OPERATING
Safety is the responsibility of the user
APARATO DE VOLTAJE ALTO
SIRVANSE LEER ESTE LIBRO CON CUIDADO
ANTES OE OPERARLO
La seguridad es el cargo del operador
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Copyright 1985-2005 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. Specifications are
subject to change without notice.
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Megger
Valley Forge Corporate Center
2621 Van Buren Avenue
Norristown, PA 19403-2329 USA
Tel: 610-676-8500
Fax: 610-676-8610
www.megger.com
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AVTM22-15Ja Rev. B December 2008
Table of Contents
1 INTRODUCTION.................................................................................... 1
2 SAFETY PRECAUTIONS ...................................................................... 3
3 RECEIVING INSTRUCTIONS ............................................................ 7
4 SPECIFICATIONS ................................................................................... 9
5 DESCRIPTION ....................................................................................... 15
General.......................................................................................................15
Electrical ....................................................................................................15
Power Supply Option ..............................................................................17
Overcurrent and Overvoltage Trip........................................................18
6 CONTROL AND CONNECTOR IDENTIFICATION ............... 25
7 SETTING UP........................................................................................... 27
Preparation ................................................................................................27
Selection of Location...............................................................................27
Connections Procedure ...........................................................................28
Clearances..................................................................................................29
Power Supply Option, Catalog No. 220015-47...................................30
8 OPERATION........................................................................................... 35
Test Procedure..........................................................................................35
Breakdown of Test Item .........................................................................36
Normal Shutdown Procedure.................................................................37
Interrupting a Test....................................................................................37
9 OPERATION NOTES........................................................................... 39
Line Voltage ..............................................................................................39
Meter Range Settings During Transit....................................................39
Stabilizing Switch......................................................................................40
Stabilizing Switch (-50 Option)..............................................................40
Use of Guard.............................................................................................41
Voltage Control Scale ..............................................................................41
Use of Regulation Curve (-50 Option) .................................................42
Step Voltage Testing ................................................................................42
Fault Locating (Breakdown Testing).....................................................42
External Current Meter ...........................................................................44
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AVTM22-15Ja Rev. B December 2008
10 APPLICATION NOTES......................................................................47
Theory of Insulation Testing ..................................................................47
Applying the Test Set to Grounded Test Object.................................48
Three-Terminal vs. Two-Terminal Tests ..............................................49
Measuring an Ungrounded Test Item....................................................49
Generalized Combined 2 and 3 Terminal Measurement....................51
11 ROUTINE MAINTENANCE .............................................................53
Introduction...............................................................................................53
Inspection and Maintenance Procedure................................................53
12 TROUBLESHOOTING AND REPAIR..........................................57
General .......................................................................................................57
Case Repairs...............................................................................................58
Repairs to Components of Chassis And Panel ....................................58
Changing Line Voltage Tap (-47 Models Only)...................................59
Replacement of Output Cable W101 ....................................................59
Replacement of Meters or Meter Amplifier Board .............................60
Replacement of Current Meter Range Circuit......................................60
Replacement of Voltmeter Range Circuit.............................................60
Replacement of Stabilizing Switch S1....................................................61
Replacement of Circuit Breakers............................................................61
Replacement of Voltage Control Autotransformer T1 ......................62
Replacement of the K2 Assembly..........................................................62
Replacement of Chassis-Mounted Assemblies ....................................62
Replacement of Circuit Card U2............................................................63
Calibration of Voltmeter..........................................................................63
Calibration of Current Meter ..................................................................64
Adjustment of R1 in Stabilization Network (-50 Option) .................66
Catalog No. 220015-50 ............................................................................66
Catalog No. 220015-47,-50......................................................................67
Trouble Location Chart ...........................................................................68
13 PERFORMANCE CHECK .................................................................73
14 PARTS LIST............................................................................................75
15 WARRANTY AND REPAIRS............................................................77
Warranty.....................................................................................................77
Repairs ........................................................................................................77
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AVTM22-15Ja Rev. B December 2008
List of Figures
Figure a: The Megger Catalog No. 220015 DC Dielectric Test Set........ 2
Figure 1: Schematic Diagram of Catalog No. 220015............................. 19
Figure 2: Schematic Diagram of Catalog No. 220015-50 ....................... 20
Figure 3: Schematic Diagram of Catalog No. 220015-42 ....................... 21
Figure 4: Schematic Diagram of Catalog No. 220015-43 ....................... 22
Figure 5: Schematic Diagram of Catalog No. 220015-101 ..................... 23
Figure 6A: Overall View of Catalog No. 220015 ..................................... 25
Figure 6B: Panel View of Catalog No. 220015.........................................26
Figure 7: Testing in a Substation................................................................. 31
Figure 8: Testing Parking Lot Lighting; the Test Set Shown is
Operating from an Inverter ....................................................... 32
Figure 9: Testing Transformer Terminals. ............................................... 33
Figure 10: DC Motor test setup................................................................. 34
Figure 11: Generator test setup.................................................................. 34
Figure 12: Regulation Curves with Stabilizer "out", 120V Supply,
-50 Option. ................................................................................ 44
Figure 13: Typical Guard Connection to Cable Pothead........................ 45
Figure 14: Guard Connection for a Typical Cable Test.......................... 45
Figure 15: Typical Guard Connection for an Oil Circuit Breaker......... 46
Figure 16: Typical Guard Connection for Transformer Test................. 46
Figure 17: Two-Winding Transformer in Three-Terminal Form.......... 50
Figure 18: Interior Views. ........................................................................... 70
Figure 19: Connections for Calibration of Voltmeter............................. 71
Figure 20: Connections for Calibration of the Current Meter............... 71
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AVTM22-15Ja Rev. B December 2008
List of Tables
Table 1: Minimum Air Clearances .............................................................29
Table 2: Measurements of Resistance........................................................50
Table 3: Trouble Location............................................................................68
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AVTM22-15Ja Rev. B December 2008
1
INTRODUCTION
This instruction manual is intended as a guide to the operation
and maintenance of the portable Dielectric Test Set, Megger
Catalog No. 220015 series.* References in this manual to
optional functions and equipment may be disregarded when
such information does not apply to the Test Set in use.
The instructions and suggestions provided in this manual
anticipate the normal use of the Dielectric Test Set for testing
electrical insulation systems on such equipment as motors,
generators, bushings and cables. These tests which are based
on measurement of the applied dc voltage, the resulting current
and the manner in which current varies with time, provide data
that indicate the condition of the insulation system of the unit
being tested. When these data are recorded on graph paper,
such as Megger Kilovolt-Megohm Paper (Part No. 220000),
the shape of the curve made by connecting the plotted points
will aid in evaluating the conditions of the insulation system.
Information on the interpretation of observed data and guides
for test voltage and time are given in Section 10 of this manual.
The basic available options covered by this manual are:
-42 Adjustable overcurrent trip setting on microammeter.
-43 Adjustable overvoltage trip setting on kilovoltmeter.
-47 Operation from input line voltage other than nominal
115 volts (Specify voltage from 100 to 240 volts).
-50 Internal voltage stabilization circuits to suppress input
transient voltages.
* This manual is intended for use with sets manufactured after
January 1985.
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AVTM22-15Ja Rev. B December 2008
Figure a: The Megger Catalog No. 220015
DC Dielectric Test Set
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AVTM22-15Ja Rev. B December 2008
2
SAFETY PRECAUTIONS
SAFETY IS THE RESPONSIBILITY OF THE USER
LA SEGURIDAD ES LA RESPONSABILIDAD DEL OPERADOR
The Test Set and the equipment to which it is connected are a
source of high-voltage electrical energy. All persons
performing or assisting in the tests must use all practical safety
precautions to prevent contact with energized parts of the test
equipment and associated circuits. Persons actually engaged in
the test must stand clear of all parts of the complete high-
voltage circuit unless the Test Set is de-energized and all parts
of the test circuit are grounded. Persons not directly associated
with the work must be kept away from test activities by
suitable barriers, barricades or warnings.
The Test Set panel must be connected to a reliable local
ground to prevent possible shock danger to the operator. Since
the energized test setup may induce a static voltage charge on
nearby insulated objects, including people, all insulated objects
must be grounded or kept at least two feet (61 cm) from the
energized structure.
G CAUTION!
Never connect the Test Set to energized
equipment or use the Test Set in an explosive
atmosphere.
All apparatus to be tested should be bonded to ground except
during the actual test. Note that even isolated conductors may develop
static voltage with respect to ground due to nearby electric fields, wind
friction or passing electrified clouds. Test connections should be
made with the ground bonds in place.
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AVTM22-15Ja Rev. B December 2008
At the completion of a test, after the power source has been
shut down and the Test Set kilovoltmeter reads zero, all
energized parts of the test setup must be short-circuited by
means of a safety grounding stick (hot stick). Ground bonds
should then be applied to the equipment that was tested. These
bonds should be left in place until access to the equipment is
again required.
If the Test Set is operated in accordance with the safety
precautions noted above and in Sections 7 and 8, and if all
grounds are correctly made, rubber gloves are not necessary.
As a routine safety procedure however, some users require that
rubber gloves be worn not only when making connections to
the high-voltage terminals, but also when manipulating
controls. Megger considers this an excellent safety practice.
Megger strongly recommends the general safety practices
contained in IEEE Std. 510 "IEEE Recommended Practices for
Safety in High-Voltage and High-Power Testing" as a guide for all
high-voltage testing. Do not, however, use this standard to
reduce any of the precautions given in this manual.
HEART PACEMAKERS
High-voltage discharges and other sources of strong electric or
magnetic fields may interfere with the proper functioning of
heart pacemakers. Personnel using heart pacemakers should
obtain expert advice on the possible risks before operating this
equipment or being close to the equipment during operation.
OTHER PRECAUTIONS
Be especially careful when testing apparatus having high
capacitance such as cables. These items store a dangerous
charge, even at low voltage.
Identify apparatus terminals and verify apparatus ground
prior to making connections.
SAFETY PRECAUTIONS
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AVTM21-415Ja Rev. B December 2008
F WARNING!
Do not use the Cat. No. 220015 Series Test Set for
any purpose not described in this Instruction Manual,
and do not use accessory items (cables, grounding
sticks, etc.) for any purpose except with the specified
equipment.
Read and follow the instruction manual.
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AVTM22-15Ja Rev. B December 2008
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AVTM22-15Ja Rev. B December 2008
3
RECEIVING INSTRUCTIONS
When your instrument arrives, check the equipment received
against the packing list to ensure that all materials are present.
Notify:
Megger
Valley Forge Corporate Center
2621 Van Buren Avenue
Norristown, PA 19403 U.S.A.
610.676.8500
of any shortage of materials.
Examine the instrument for damage received in transit. If any
damage is discovered, file a claim with the carrier at once and
notify Megger or its nearest authorized sales representative,
giving a detailed description of the damage observed.
This instrument has been thoroughly tested and inspected to
meet rigid inspection specifications before being shipped. It is
ready for use when set up as indicated in Section 7.
A qualified person should become familiar with this entire
Manual and make a test run. This pre-test serves both to
familiarize the user with the Test Set and to check that the set
is operating properly.
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4
SPECIFICATIONS
POWER SUPPLY: Catalog No. 220015
Voltage (rms): 105 -130 Volts
Recommended Source: NEC 15 Ampere, 120 Volts,
single-phase branch circuit
(3 wire: line, neutral and ground).
Current (rms): 1.5 Amps, maximum continuous.
Frequency: 60 Hz, full rating
50 Hz, reduced rating
Basis of Rated
performance:
120-Volt, 60 Hz supply
with stabilizer out.
OPTIONAL SUPPLY: Catalog No. 220015-47
Voltage (rms): Specify nominal voltage on order.
Current (rms): NOMINAL RANGE MAXIMUM
CURRENT
210 208 to 225 0.80
230 225 to 240 0.83
250 240 to 265 0.85
Recommended Source: 10-Ampere, nominal voltage,
single-phase branch circuit.
Frequency: 60 Hz full rating;
50 Hz reduced rating.
Basis of Rated
performance:
230 Volt, 60 Hz supply with
stabilizer out.
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AVTM22-15Ja Rev. B December 2008
OUTPUT TEST
VOLTAGE:
0-15 kV dc, negative with respect
to ground.
OUTPUT CURRENT:
Standard or with stabilizer
out (-50 option) at 60 Hz:
2 mA continuous,
5 mA for 12 minutes.
at 50 Hz: 1.67 mA continuous,
4.17 mA for 12 minutes
With stabilizer in (-50
option) at 50 or 60 Hz:
At 15 kV, 50 µA continuous.
Short Circuit: 12 mA maximum,
limited by circuit breaker
RIPPLE VOLTAGE (rms): 1% at 3 MΩ resistive load.
OUTPUT VOLTAGE REGULATION:
Standard or with internal
stabilizer out (-50 option): 13% no load to 7.5 MΩ load plus
or minus percent change in line
voltage.
With internal stabilizer in
(-50 option):
0.1% no load to 300 MΩ load,
including ±10% line voltage
change.
METERING:
Kilovoltmeter: 4-inch taut-band
2-range: 0-7.5 and 0-15.0kV:
±2% FS
Current: 4-inch, taut-band
4-range: 0-5/50/500 µA and 5mA
±2% FS
SPECIFICATIONS
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AVTM21-415Ja Rev. B December 2008
CONTROLS:
Power OFF-ON switch (Circuit Breaker) with green lamp
indicator.
High-voltage OFF-ON switch (Circuit Breaker) with red lamp
indicator.
Voltage control with Zero-Start interlock, 0-100 reference dial.
Stabilizer selector switch: IN-OUT.
Voltmeter Range Switch: 7.5-15 kV.
Ammeter multiplier switch, 4-position: x1, x10, x100, x1K
CABLES and CONNECTORS
Power Supply Cord: 7½ feet (2.3 meters),
3-wire with plug
Output Cable: Attached; shielded with GUARD
terminal, high-voltage clip and
boot; 15 feet (4.6 meters) long.
Ground Cable: Separate, 10 feet (3.3 meters)
with positive action clamp at
outboard end.
Ground Terminal: ¼ inch stud with wing nut.
External Instrument Jack: Accepts ¼ inch 2-wire phone plug
for connecting external recorder or
current meter to read current in
test item.
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AVTM22-15Ja Rev. B December 2008
PHYSICAL:
Case: High-impact structural foam,
polycarbonate plastic with metal
control panel and removable
hinged lid.
Size: Overall
Width Depth Height
20 ½ 12 13 inches
52 30.5 33 cm
Weight:
Catalog No. 220015: 35 ¼ lbs. (16 kg)
Catalog No. 220015-47: 39 ½ lbs. (18 kg)
Instruction Card: Permanently attached inside lid.
Cable & Manual Storage: Fit in compartment in case.
ENVIRONMENT:
Temperature: 0°F (-17.7°C) to 122°F (50°C)
maximum operating.
Altitude: 10,000 feet (3,048 meters)
maximum operating.
Relative Humidity: Non-condensing conditions.
Shock and Vibration: Will withstand normal shock and
vibration encountered in field use
and transportation.
PROTECTIVE FEATURES:
Dual overload protection for all overload conditions by
two separate circuit breakers.
Metering protected against overload and transient
conditions.
SPECIFICATIONS
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AVTM21-415Ja Rev. B December 2008
SAFETY FEATURES:
"Zero start" interlock: Voltage Control must be at zero
to enable the output voltage circuit to be energized
(started).
Grounded metal control panel.
Separate visible panel ground cable.
Permanently attached shielded output cable.
Separate switches for control power and high-voltage
output.
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