Megger MWA3 Series User manual

MWA300_330A-UG-EN-V05
May 2017
Instruction Manual
for
Three-Phase Ratio & Winding Resistance
Transformer Test Set
MWA3XX Series
Catalog Numbers. MWA300, MWA300-47,
MWA330A, MWA330A-47
HIGH-VOLTAGE EQUIPMENT
Read this entire manual before operating equipment
Valley Forge Corporate Center
2621 Van Buren Avenue
Norristown, PA 19403-2329
U.S.A.
610-676-8500
www.megger.com

Three-Phase Ratio & Winding Resistance
Transformer Test Set
MWA3XX Series

Copyright© 2017 by Megger. All rights reserved.
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 first be authorized for return via
email to [email protected], and upon receipt of an RA # be shipped prepaid and insured. The
warranty is void in the event of abuse (failure to follow recommended operating procedures) or failure
by the customer to perform specific routine maintenance as indicated in this manual.
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Valley Forge Corporate Center
2621 Van Buren Ave
Norristown, PA 19403-2329
610-676-8500 (Telephone)
610-676-8610 (Fax)
www.megger.com

MWA300_330A-UG-EN-V05 May 2017 i
Table of Contents

1 MWA300 PRODUCT OVERVIEW................................................................................................................1
2 SAFETY ... ............................................................................................................................................................5
3 SPECIFICATIONS.............................................................................................................................................7
Electrical...................................................................................................................................................................7
Input Power......................................................................................................................................................7
Protective Devices (Fuses) .............................................................................................................................7
Ratio Specifications.................................................................................................................................................8
Output AC Test Voltage and Current ..........................................................................................................8
Test Frequency.................................................................................................................................................8
Loading of Test Transformer ........................................................................................................................8
Measuring Ranges ...................................................................................................................................................8
Accuracy............................................................................................................................................................8
Measurement Method.............................................................................................................................................9
Transformer Winding Phase Relationship ..........................................................................................................9
Measuring Time.......................................................................................................................................................9
Winding Resistance Specifications........................................................................................................................9
DC Output Current (User selectable Ranges).............................................................................................9
Open Circuit Test Voltage..............................................................................................................................9
Measurement Voltage......................................................................................................................................9
Max Power........................................................................................................................................................9
Resistance ranges: ......................................................................................................................................... 10
Display ................................................................................................................................................................... 10
Memory Storage ................................................................................................................................................... 10
Communication Interface................................................................................................................................... 10
Safety/EMC/Vibration....................................................................................................................................... 10
Environmental Conditions ................................................................................................................................. 11
Physical Data......................................................................................................................................................... 11
4 SOFTWARE INSTALLATION.................................................................................................................... 13
PowerDB Lite Setup & Installation (PC Control only).................................................................................. 13
Software Installation (PC portion only)............................................................................................................ 14
General Testing Procedures ............................................................................................................................... 15
Getting Started .............................................................................................................................................. 15
5 THREE-PHASE TTR & WINDING RESISTANCE TESTING.......................................................... 19
Select 3ƟTurns Ratio & Winding Resistance form........................................................................................ 19
Test Form Controls - General............................................................................................................................ 20
Form Settings:....................................................................................................................................................... 21
Tap Settings........................................................................................................................................................... 22
Resistance/Ratio Settings.................................................................................................................................... 23
Transformer Nameplate...................................................................................................................................... 24
Transformer Test Conditions............................................................................................................................. 25
Ratio Test Set Up................................................................................................................................................. 25
Ratio Test .............................................................................................................................................................. 26
Winding Resistance Testing................................................................................................................................ 27
Method 1 - Resistance Test Wizard................................................................................................................... 28
Method 2 – Measuring Tap – All Phases Winding Resistance...................................................................... 29
Method 3 – Measuring Individual Tap Winding ............................................................................................. 30

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Resistance Test Screen .........................................................................................................................................31
Basic Connections to MWA300/330A..............................................................................................................32
6 TRANSFORMER TESTING APPLICATIONS – RATIO & WINDING.........................................33
Single-Phase, Two-Winding Transformers – including Typical Pole Type transformers with Dual
Secondary’s.............................................................................................................................................................34
Three-Phase, Two-Winding Transformers .......................................................................................................37
Three-Phase, Three-Winding Transformers.....................................................................................................39
Current Transformers (CTs) ...............................................................................................................................39
Unmounted CTs ...................................................................................................................................................40
Bushing Current Transformer (BCT) Mounted on Single-Phase, Two-Winding Transformer................42
Bushing Current Transformer (BCT) Mounted on Three-Phase Transformers.........................................43
7 TEST & RESULTS FILES - SAVING AND RETRIEVING..................................................................47
Saving Results/Test Files.....................................................................................................................................47
Retrieving Results/Test Files ..............................................................................................................................48
8 SERVICE. ..........................................................................................................................................................51
Maintenance...........................................................................................................................................................51
Calibration..............................................................................................................................................................51
Ratio Portion – Self-Check..................................................................................................................................51
Reason for Possible Inaccuracy in 1:1 Self-Test:..............................................................................................52
Troubleshooting....................................................................................................................................................53
Resolving MWA Connection Issues (PC portion only)...........................................................................53
Ratio Testing ..................................................................................................................................................55
Error Messages..........................................................................................................................................55
The TTR Troubleshooting Guide......................................................................................................................57
Repairs ....................................................................................................................................................................58
9 ORDERING INFORMATION / SPARE PARTS....................................................................................59

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LIST OF FIGURES

Figure 1-1 Top Panel Controls ...............................................................................................................................2
Figure 6-1......Setup for Testing Single-Phase Transformer (Vector Diagram 1P0).................................... 34
Figure 6-2......Setup for Testing Single-Phase Autotransformer (Vector Diagram 1P0) ............................ 34
Figure 6-3......Setup for Testing Single-Phase, Type A (Straight Design) Step Voltage Regulator ........... 35
Figure 6-4......Setup for Testing Single-Phase, Type B (Inverted Design) Step Voltage Regulator .......... 36
Figure 6-5......Connections to a Pole Type Transformer with 2 secondary windings.................................. 36
Figure 6-6 .....Typical Connection to a 2 Winding YNyn or ZigZag – 8 Terminal Transformer ............. 38
Figure 6-7......Typical Connection to a Delta Delta or Yy (no neutral) 6 terminal transformer................. 38
Figure 6-8......Setup for Testing Unmounted Current Transformer.............................................................. 41
Figure 6-9......Setup for Testing Taps on Multiple Tap CT ............................................................................ 41
Figure 6-10....Setup for Testing BCT Mounted on Single-Phase Two-Winding Transformer ................. 42
Figure 6-11....Setup for Testing BCT Mounted on Delta Winding Three-Phase Power Transformer.... 44
Figure 6-12....Setup for Testing BCT Mounted on Wye Winding of a Three-Phase Transformer .......... 45
LIST OF TABLES
Table 6-1........Test Lead Markings for Single-Phase Transformers ............................................................... 35
Table 6-2........Test Lead Markings for Three-Phase Transformers................................................................ 37
Table 8-1........Troubleshooting Guide................................................................................................................ 57
Table 9-1........Replacement Parts List................................................................................................................. 59

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Upon Receipt of Product
Prior to operation, check for loosened hardware or damage incurred during
transit. If these conditions are found, a safety hazard is likely, DO NOT attempt
to operate equipment. Please contact Megger as soon as possible.
MWA300 Transformer Ratio & Winding Resistance Test Set

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MWA300 PRODUCT OVERVIEW
The MWA300/330A test set is an automatic unit which is designed to be
controlled via a computer running PowerDB Lite software. The MWA330A
includes a built-in 12 inch controller which is used in place of a PC. The test set
measures the turns ratio, phase shift, excitation current and winding resistance of
power, distribution, and instrument transformers. A"-47" suffix added to the
catalog number denotes a 50 Hz input power supply frequency. The test set is a
portable instrument housed in a sturdy plastic case. A carry bag is supplied for
accessories.
The test set can be used to test single-phase and three-phase transformers, both
with and without taps in accordance with the requirements of the IEEE
C57.12.90 – 2013 as well as IEC 60076-1 standards. For three-phase
measurements, the test set is connected to all three phases of the transformer to
be tested. Operating condition (error) messages identify incorrect test
connections, abnormal operating condition, or winding problems. Test results
are saved to an external PC.
It is recommended that the user becomes familiar with the MWA300/330A
before ever connecting to a transformer.

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Top Panel Controls
Figure 1-1 Top Panel Controls
1. Power Input Receptacle: ON/OFF switch, and Mains fuse holder.
ON/OFF power switch and input power receptacle provides power to the test
set.
2. H – Cable Receptacle: Plug receptacle for connecting test leads to the high-
voltage (H) winding of a transformer
3. X – Cable Receptacle: Plug receptacle for connecting test leads to the low-
voltage (X) winding of a transformer.
4. PC Input: USB host for PC control connection of MWA. Switch used to select
external (MWA300 always in this position) as well as internal (MWA330A only)
control of instrument. Software provided is PowerDB Lite version 11.03 and
higher.
5. HV Strobe Input Connector: When the optional HV Strobe (Cat # 1004-639)
is attached, the user will have a highly visible indication of the test voltage or test
current being applied to the Unit Under Test (UUT).
6. Safety Interlock Input: These connections are used when there is requirement
for additional safety while testing a transformer.
7. Ground Lug: Special twist lock terminal allows connection of test set to Station
Earth ground.
8. Voltage ON Light: Flashing Red indicator lamp indicates ac test voltage or dc
test current is being supplied to the Unit Under Test (UUT).
9. Test Mode Indicator: LEDs light up to indicate which test state instrument is
in (MTO or TTR).

Product Overview
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MWA330A Optional Controller with Display
The optional industrial 12 inch controller is:
1. Industrial 300 mm (12 inch) Touch Display: Used in place of a PC.
Designed to run PowerDB Lite with focus on selected Megger instrument
control related to transformer testing. When turned on, defaults to MWA
transformer forms.
2. Built-in Printer: Designed to print individual results and is active within
specific forms via 'print icon' located within selected forms.
3. USB Port: Used for various functions including external memory and
external mouse/keyboard control.
4. Rear USB Port Hub: Used for external Megger instrument control such as
Delta4000, S1/MIT Insulation test set, MLR10.
5. Rear Ethernet Port: Used for external Megger instrument control –
specifically the Delta4000.
The MWA330A 300 mm (12 inch) display is meant to replace a customer PC
with an industrial controller designed to work in harsh environments. This built-
in display features protection against accidental shut down of the instrument by
safely turning off Windows operating system together with PowerDB after
shutdown (switch is turned off) is detected. This safe shutdown prevents damage
to the internal memory, and to the software operating system.

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SAFETY
Safety is the Responsibility of the User
Only qualified and trained operators should operate the MWA300. Operator
must read and understand this entire Instruction Manual prior to operating the
equipment. Operator must follow the instructions of this Instruction Manual and
attend the equipment while the equipment is in use. In the event of equipment
malfunction, the unit should immediately be de-energized and returned to
Megger for repair. The Safety precautions, herein, are not intended to replace
your Company’s Safety Procedures. Refer to IEEE 510 - 1983, IEEE
Recommended Practices for Safety in High-Voltage and High-Power Testing, for additional
information.
General Safety Precautions
The MWA300 and the Unit Under Test (UUT) should both be considered as
sources of instantaneously lethal levels of electrical energy. Observe the
following safety precautions:
Observe all safety warnings on the equipment. They identify areas of
immediate hazard that could result in injury or death.
Use this equipment only for the purposes described in this manual. Observe
strictly the Warning and Caution information provided in this manual
Treat all terminals of high-voltage power equipment systems as potential
electric shock hazards. Use all practical safety precautions to prevent contact
with energized parts of the equipment and related circuits.
Use suitable barriers, barricades, or warnings to keep persons not directly
involved with the work away from test activities.
Never connect the test equipment to energized equipment.
Do not use in an explosive atmosphere.
Use the grounding and connection procedures recommended in this manual.
Always disconnect test leads from power equipment before attempting to
disconnect them at the test set. The ground connection must be the first
made and the last removed. Any interruption of the grounding connection
can create an electrical shock hazard.

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Personnel using heart pacemakers should obtain expert advice on the
possible risks before operating this equipment or being close to the
equipment during operation.
Input Power Precautions
This instrument operates from a single-phase, sine wave, power source. It has a
three-wire power cord and requires a two-pole, three-terminal (live, neutral, and
ground) type input source. The voltage to ground from the live pole of the
power source must be within the following rated operating voltage:
Cat. No MWA300/330A 108-132V, (207-253V*), 60 Hz, 2 Hz, 660VA
Cat. No. MWA300/330A-47 207-253V, (108-132V*) 50 Hz, 2 Hz, 660VA
*- Requires a fuse change for correct operation – see Specifications below
The neutral pole must be at ground potential. Before making connection to the
power source, determine that the instrument rating matches the voltage of the
power source. The power input plug must be inserted only into a mating
receptacle with a ground contact. Do not bypass the grounding connection. Any
interruption of the grounding connection can create an electric shock hazard.
Determine that the receptacle is properly wired before inserting the plug.
For test sets energized with 230V input, the neutral terminal of the input supply
cord (white or blue lead) must be connected to the neutral pole of the line power
source. The ground terminal of the input supply cord (green or yellow/green
lead) must be connected to the protective ground (earth) terminal of the line
power source. The black or brown cord lead is the live (hot) lead.
The control circuits of the instrument are protected by two mains circuit fuses.
These fuses are located in the ON/OFF switch module and are replaceable by
the operator. To avoid electric shock and fire hazard, use only the fuse specified
in Section 3 that is identical in respect to type, voltage rating, and current rating.
F WARNING
Before replacing the fuses, disconnect the power input
plug from the live power source.

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SPECIFICATIONS
Electrical
Input Power
Cat. No.
MWA300/330A: 108-132V, 60 Hz, ±2 Hz, 660 VA (207-253V with fuse change to 4.0 amp*)
IEC 1010-1 installation category II
*Calibration of phase may differ if nominal line frequency
changes.
Cat. No.
MWA300/330A-47: 207-253V, 50 Hz, ±2 Hz, 660 VA (108-132V with fuse change to 6.3 amp*)
IEC 1010-1 installation category II
*Calibration of phase may differ if nominal line frequency
changes.
Protective Devices (Fuses)
Main Input Fuse :
TTR Portion:
Qty 2: 6.3 amp, 250V, 5x20mm, SLO-BLO (120V Ceramic)
Qty 2: 4.0 amp, 250V, 5x20mm, SLO-BLO (230V Ceramic)
0.5 amp, 250V, 5x20mm, SLO-BLO

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RATIO SPECIFICATIONS
Output AC Test Voltage and Current
Test Voltages: 80V rms, 40V rms, 8V rms
Current: up to 500 ma
Test Frequency
Same as line frequency
Loading of Test Transformer
Less than 0.2 VA
Measuring Ranges
Turns Ratio: 80V ac: 0.8 to 45,000, 5 digit resolution
40V ac: 0.8 to 25,000, 5 digit resolution
8V ac: 0.8 to 8,000, 5 digit resolution
Excitation Current: 0 to 500 mA, 3 digit resolution
Phase Angle Deviation: ± 90 degrees, 1 decimal point for the minutes display, 2 decimal
point for the degree display
Accuracy
80V ac: ±0.1% (0.8 to 2000)
±0.15% (2001 to 4000)
±0.25% (4001 to 10000)
±0.3% (10001 to 45000)
40V ac: ±0.1% (0.8 to 2000)
±0.15% (2001 to 4000)
±0.3% (4001 to 10000)
±0.35% (10001 to 25000)
8V ac: ±0.1% (0.8 to 2000)
±0.25% (2001 to 4000)
±0.35% (4001 to 8000)
Resolution: 5 digits for all ratios
Excitation Current (rms): ±(2% of reading + 1 digit)
Phase Angle Deviation: ±3 minutes ( ± 0.05 degrees)

Specifications
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Measurement Method
In accordance with ANSI/IEEE C57.12.90-2013 and IEC 60076-1
Transformer Winding Phase Relationship
ANSI C57.12.70-2011
CEI/IEC 76-1:2011, IEC 60076-1 and CIGRE TB 445
AS-2374, Part 4-2003 (Australian Standard)
Measuring Time
8 to 37 seconds depending on mode of operation and type of transformer
Winding Resistance Specifications
DC Output Current (User Selectable Ranges)
10 mA
100 mA
1 A
2.5 A
5.0 A
7.5 A
10 A
Open Circuit Test Voltage
40V dc
Measurement Voltage
20V dc
Max Power
200VA continuous

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Resistance Ranges
Current Range (A) Resistance Range (Ω) Resolution ((Ω)
10 A 10 µΩto 0.2 Ω0.000001
10 A 0.2 Ωto 2 Ω0.0001
1 A 100 µΩto 2 Ω0.00001
1 A 2 Ωto 20 Ω0.001
100 mA 1 mΩto 20 Ω0.0001
100 mA 20 Ωto 200 Ω0.01
10 mA 10 mΩto 200 Ω0.001
10 mA 200 Ωto 2000 Ω0.1
Accuracy: +/-0.25% Range +/-0.25% rdg
Display
MWA300: Via external PC (user supplied)
MWA330A: Size: 12 inch (305mm), Brightness: 1600 NIT, Operating Temp
Range: -10C to +50C operation, Type: 4 wire resistive (touch)
Memory Storage
MWA300: Via external PC (user supplied)
MWA330A: 32GB internal
Communication Interface
MWA300: USB 2.0 Serial
MWA330A: Internal for MWA operation or external port USB 2.0 Serial, or
Ethernet 10/100 for Delta4000/S1/MIT/MLR10 operation.
(The 12 inch display is able to control above instruments via
PowerDB software installed within the instrument.
Safety/EMC/Vibration
Conforms to the requirements of:
IEC1010-1: 2010 CE
ASTMD999.75
IEC 61326-1:2012*
*At radiated frequencies 80MHz – 100MHz, performance may be deteriorated.

Specifications
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Environmental Conditions
Operating Temperature Range: 14°to 122°F (-10 to 50 °C)
Storage Temperature Range: -22°to 158°F (-30 to 70 °C)
Relative Humidity: 0 to 90% noncondensing
Physical Data
Dimensions:
Instrument:
11.5 H x 11.5 W x 18 D in. (290H x 290 W x 460D mm)
Weight:
MWA300 with standard provided accessories: 34 lbs. (15.5 kg)
MWA330A with standard provided accessories: 39 lbs (18.0 kg)
with Optional Leads, 30 ft (9m) Add 18 lbs (+8 kg)

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