Megger MWA300 Series User manual

MWA300-UG-EN-V2
November 2016

Instruction Manual
for
Three-Phase Ratio & Winding Resistance
Transformer Test Set
MWA300 series
Catalog Numbers. MWA300, MWA300-47
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
MWA300 series

Copyright© 2016 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

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Table of Contents
1 MWA300 Product Overview..............................................................................................................................1
2 SAFETY ... ............................................................................................................................................................3
3 SPECIFICATIONS.............................................................................................................................................5
Input Power......................................................................................................................................................5
Protective Devices (Fuses) .............................................................................................................................5
Output AC Test Voltage and Current ..........................................................................................................5
Test Frequency.................................................................................................................................................5
Loading of Test Transformer ........................................................................................................................6
Accuracy............................................................................................................................................................6
DC Output Current (User selectable Ranges).............................................................................................7
Open Circuit Test Voltage..............................................................................................................................7
Measurement Voltage......................................................................................................................................7
Max Power........................................................................................................................................................7
Resistance Ranges:...........................................................................................................................................7
4 SOFTWARE INSTALLATION.......................................................................................................................9
Getting Started .............................................................................................................................................. 11
5 THREE PHASE TTR & WINDING RESISTANCE TESTING .......................................................... 15
Select 3ƟTurns Ratio & Winding Resistance form............................................................................ 15
Test Form Controls - General................................................................................................................ 16
Form Settings:........................................................................................................................................... 17
Tap Settings............................................................................................................................................... 18
Resistance/Ratio Settings........................................................................................................................ 19
Transformer Nameplate.......................................................................................................................... 20
Transformer Test Conditions................................................................................................................. 21
Ratio Test Set Up ..................................................................................................................................... 21
Ratio Test .................................................................................................................................................. 22
Winding Resistance Testing.................................................................................................................... 23
Method 1 - Resistance Test Wizard - .................................................................................................. 24
Method 2 – Measuring Tap – All Phases Winding Resistance ......................................................... 25
Method 3 – Measuring Individual Tap Winding ................................................................................. 25
Resistance Test Screen............................................................................................................................. 26
6 TRANSFORMER TESTING APPLICATIONS – RATIO & WINDING......................................... 29
7 TEST & RESULTS FILES - SAVING AND RETRIEVING................................................................. 43
Saving Results/Test Files.................................................................................................................................... 43
Retrieving Results/Test Files ............................................................................................................................. 44
8 SERVICE .47
Calibration................................................................................................................................................. 47
Ratio Portion – Self check ...................................................................................................................... 48
Reason for Possible Inaccuracy in 1:1 Self-test: .................................................................................. 48
Error Messages ......................................................................................................................................... 49
9 ORDERING INFORMATION / SPARE PARTS ................................................................................... 53

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LIST OF FIGURES

Figure 6-1......Setup for Testing Single-Phase Transformer (Vector Diagram 1P0).....................................30
Figure 6-2......Setup for Testing Single-Phase Autotransformer (Vector Diagram 1P0).............................30
Figure 6-3......Setup for Testing Single-Phase, Type A (Straight Design) Step Voltage Regulator ............31
Figure 6-4......Setup for Testing Single-Phase, Type B (Inverted Design) Step Voltage Regulator...........32
Figure 6-5......Showing connections to a Pole Type Transformer with 2 secondary windings ..................32
Figure 6-6 .....Shows a Typical Connection to a 2 Winding YNyn or ZigZa – 8 Terminal Transformer34
Figure 6-7......Shows a Typical Connection to a Delta Delta or Yy (no neutral) 6 terminal transformer.34
Figure 6-8......Setup for Testing Unmounted Current Transformer...............................................................37
Figure 6-9......Setup for Testing Taps on Multiple Tap CT.............................................................................37
Figure 6-10....Setup for Testing BCT Mounted on Single-Phase Two-Winding Transformer ..................38
Figure 6-11....Setup for Testing BCT Mounted on Delta Winding on a 3-Phase Power Transformer ....40
Figure 6-12....Setup for Testing BCT Mounted on Wye Winding of a Three-Phase Transformer...........41
LIST OF TABLES
Table 6-1 .......Test Lead Markings for Single-Phase Transformers ................................................................31
Table 6-2 .......Test Lead Markings for Three-Phase Transformers ................................................................33
Table 8-1 .......Troubleshooting Guide.................................................................................................................50
Table 9-1 .......Replacement Parts List .................................................................................................................53

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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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1
MWA300 Product Overview
The MWA300 test set is an automatic unit which is designed to be controlled via
a computer running PowerDB Lite software. 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 230V /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 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).

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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 120 V 10%, 60 Hz, 2 Hz, 660VA
Cat. No. MWA300-47 230 V 10%, 50 Hz, 2 Hz, 660VA
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 230 V input (MWA300-47), 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: 120 V, ±10%, 60 Hz, ±2 Hz, 660 VA
IEC 1010-1 installation category II
Cat. No. MWA300-47: 230 V, ±10%, 50 Hz, ±2 Hz, 660 VA
IEC 1010-1 installation category II
Protective Devices (Fuses)
Main Input Fuse :
TTR portion:
MWA300:
Qty 2: 6.3 amp, 250V, 5x20mm, SLO-BLO (120V Ceramic)
Qty 2: 4.0 amp, 250V, 5x20mm, SLO-BLO (230V Ceramic)
1.0 amp, 250 V, 5x20mm, SLO-BLO (120V)
MWA300-47: 0.5 amp, 250V, 5x20mm, SLO-BLO (230V)
RATIO SPECIFICATIONS
Output AC Test Voltage and Current
Test Voltages: 80 V rms, 40 V rms, 8 V rms.
Current: up to 500 ma
Test Frequency
Same as line frequency.

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Loading of Test Transformer
Less than 0.2 VA
Measuring Ranges
Turn ratio: 80 V ac: 0.8 to 45,000, 5 digit resolution
40 V 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
80 V ac: ±0.1% (0.8 to 2000)
±0.15% (2001 to 4000)
±0.25% (4001 to 10000)
±0.3% (10001 to 45000)
40 V ac: ±0.1% (0.8 to 2000)
±0.15% (2001 to 4000)
±0.3% (4001 to 10000)
±0.35% (10001 to 25000)
8 V 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)
Measurement Method
In accordance with ANSI/IEEE C57.12.90-2013 & 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)

Specifications
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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
40 V dc
Measurement Voltage
20 V dc
Max Power
200 VA continuous
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

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Display
Via external PC (user supplied)
Memory Storage
Via external PC (user supplied)
Communication Interface
USB 2.0 Serial
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.
Environmental Conditions
Operating temperature range: 23 to 122 F (-5 to 50 C)
Storage temperature range: -22 to 140 F (-30 to 60 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:
Instrument with standard provided accessories:
Instrument with Optional Leads, 30ft (9.0m)
34 lbs. (15.5 kg)
52 lbs. (23.6 kg)

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4
SOFTWARE INSTALLATION
PowerDB Lite Setup & Installation
PowerDB Lite software is included at no extra charge software tool that is
designed specifically to control and/or extract data from the MWA300.
PowerDB Lite will present your test data into a professional looking data form
that can be sent to a printer or .pdf file.
PowerDB Lite allows you to use a sub-set of the standard PowerDB forms that
are appropriate for specific Megger instruments.
Minimum Recommended System
Operating System: Windows XP or later
RAM: 2GB RAM minimum, >4GB RAM recommended
>2G free memory space
Processor: 2.0 GHz Pentium Class processor minimum,
For more information please visit www.powerdb.com or contact your local sales
representative

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Software Installation
To install PowerDB Lite, load the PowerDB Lite CD (or USB) into your
computer drive and follow the on-screen instructions. For latest version, please
go to website www.powerDB.com/download and download latest Lite version
available. The model is contained within the software and not obvious until Lite
software is loaded.
1. Accept the terms of the License agreement.
2. Choose the destination location for the PowerDB Lite files.

Software Installation
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3. Select Default Settings (Language and Units of Measure).
4. Install Shield Wizard will complete the installation of PowerDB Lite. Click
Finish to close the installation program.
General Testing Procedures
Getting Started
1. To determine that the MWA hardware is operational, observe the following:
Once all Safety precautions are taken, and all circuit connections are made, the
user may safely turn the ON/OFF switch to the ON position and operate the
test instrument as described herein.
On power up, fans should begin (winding resistance portion) to be heard
and ONE audible beep should sound (ratio portion). The MWA performs a
self-test check, and all hardware and software variables are initialized.
Proceed to Section below for operation via external PC (supplied by User).
2. Select PowerDB Lite from PC Start Menu or from Shortcut on Main window:

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3. Select MWA from the Instrument Setup screen. It may be located in “Favorites”
or “Transformer/Power Factor Test Sets” and can be relocated as desired.
The MWA300 uses USB connection only. Once MWA is selected, the proper
settings for USB are pre-selected, and no further changes should be required.
PLEASE ALLOW SUFFICIENT TIME FOR DRIVERS TO LOAD WHEN
CONNECTING TO MWA300 FIRST TIME. Each time one connects to
MWA, allow approximately 45-60 seconds for PC to connect to the instrument
once connected.
4. From Device Manager, one should see the following drivers installed with
instrument ON:
Before connection After connection+ MWA300 ON