Vanguard WRM-40 User Manual

WRM-10P and WRM-40

TRANSFORMER WINDING RESISTANCE METERS

USER’S MANUAL

Vanguard Instruments Company, Inc.

1520 S. Hellman Ave.

Ontario, California 91761, USA

TEL: [phone]	November 2009
FAX: [phone]	Revision 3

WRM-10P AND WRM-40 USER’S MANUAL REV 3

SAFETY SUMMARY

NOTICE

This manual applies to both the WRM-10P and WRM-40 transformer winding resistance meters. The operating procedures are virtually the same for both models, and any differences are clearly described where applicable.

FOLLOW EXACT OPERATING PROCEDURES

Any deviation from the procedures described in this User’s Manual may create one or more safety hazards, may damage the WRM-10P/40, damage the test transformer, or cause errors in the test results. Vanguard Instruments Company, Inc. assumes no liability for unsafe or improper use of the WRM-10P/40.

All safety precautions provided in this manual must be observed during all phases of testing including test preparation, test lead connection, actual testing, and test lead disconnection.

SAFETY WARNING AND CAUTIONS

The WRM-10P/40 shall be used only by trained operators. All transformers under test shall be off-line and fully isolated.

DO NOT MODIFY TEST EQUIPMENT

To avoid the risk of introducing additional or unknown hazards, do not install substitute parts or perform any unauthorized modification to any WRM-10P/40 test unit. To ensure that all designed safety features are maintained, it is highly recommended that repairs be performed only by Vanguard Instruments Company factory personnel or by an authorized repair service provider. Unauthorized modifications can cause safety hazards and will void the manufacturer’s warranty.

WARNING

Do not remove test leads during a test. Failure to heed this warning can result in lethal electrical shock to personnel and damage to the equipment.

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TABLE OF CONTENTS

CONVENTIONS USED IN THIS DOCUMENT .....................................................................................			1
1.0	INTRODUCTION....................................................................................................................		2
1.1	General Description and Features ...................................................................................		2
1.2	Technical Specifications ...................................................................................................		4
1.2.1.		WRM-10P Technical Specifications ..........................................................................	4
1.2.2.		WRM-40 Technical Specifications ............................................................................	5
1.3	WRM Controls and Indicators..........................................................................................		6
2.0	PRE-TEST SETUP .................................................................................................................		10
2.1	Operating Voltages ........................................................................................................		10
2.2	LCD Screen Contrast Control..........................................................................................		12
2.3	Printer Paper Control.....................................................................................................		12
2.4	Printer Paper..................................................................................................................		12
2.5	Replacing the Thermal Printer Paper.............................................................................		13
3.0	OPERATING PROCEDURES .................................................................................................		14
3.1	WRM Cable Connections ...............................................................................................		14
3.2	General Procedures .......................................................................................................		16
3.3	Entering Test Record Header Information.....................................................................		17
3.4	Performing a Resistance Test.........................................................................................		20
3.5	Performing a Load Tap Changer / Voltage Regulator Resistance Test ..........................		29
3.6	Performing a Special Resistance Test ............................................................................		36
3.7	Performing a Transient Test ..........................................................................................		41
3.8	Performing a Diagnostic Test.........................................................................................		44
3.9	Working with Test Records............................................................................................		45
3.9.1. Restoring a Test Record for Review or Printing .....................................................			45
3.9.2. Reviewing or Printing a Restored Test Record.......................................................			48
3.9.3. Printing a Test Record Directory ............................................................................			49
3.9.4.		Erasing Test Records...............................................................................................	51
3.10 Enabling the Computer Interface ..................................................................................			53
3.11 Setting the Date and Time .............................................................................................			54
4.0	WRM-10P/40 SPECIAL FEATURES ......................................................................................		55
4.1	Bypassing Resistance Reading Delay .............................................................................		55
4.2	Converting Resistance Measurements ..........................................................................		56
5.0	Troubleshooting Guide ......................................................................................................		57

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	LIST OF FIGURES
Figure 1. WRM-10P Controls and Indicators ..................................................................................		6
Figure 2. WRM-40 Controls and Indicators ....................................................................................		8
Figure 3. 100 – 120 Vac Jumper Settings ......................................................................................		10
Figure 4. 200 – 240 Vac Jumper Settings ......................................................................................		10
Figure 5. WRM-10P Relay Location...............................................................................................		11
Figure 6. WRM-40 Relay Location.................................................................................................		11
Figure 7. Typical WRM Connections Diagram #1..........................................................................		14
Figure 8. Typical WRM Connections Diagram #2..........................................................................		14
Figure 9. Typical WRM Connections Diagram #3..........................................................................		15
Figure 10. Typical WRM Connections Diagram #4........................................................................		15
Figure 11. Typical V1 Test Report Printout ...................................................................................		26
Figure 12. Typical V1 and V2 Test Report Printout.......................................................................		27
Figure 13. Typical V1 and V2 Test Report Printout with Multiple Readings ................................		28
Figure 14.	Typical LTC/Voltage Regulator Test Report Printout...................................................	35
Figure 15.	Typical Five Minute Special Test Report Printout........................................................	40
Figure 16.	Typical Transient Test Report ......................................................................................	43
Figure 17.	Typical Test Record Directory Printout........................................................................	50

	LIST OF TABLES
Table 1. WRM-10P Technical Specifications...................................................................................		4
Table 2.	WRM-40 Technical Specifications .....................................................................................	5
Table 3.	Functional Descriptions of WRM-10P Controls and Indicators ........................................	7
Table 4.	Functional Descriptions of WRM-40 Controls and Indicators ..........................................	9
Table 5.	Voltage Selection Jumper Settings..................................................................................	10

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CONVENTIONS USED IN THIS DOCUMENT

This document uses the following conventions:

•Both the WRM-10P and WRM-40 are simply referred to as “WRM” in this manual. The exact model number is used only in cases where differences between the units are discussed.

•A key, switch, or knob on the WRM is indicated as [KEY], [SWITCH], [KNOB].

•Menu names are referenced as “MENU NAME”

•WRM LCD screen output is shown as:

1.OPTION 1

2.OPTION 2

3.OPTION 3

4.OPTION 4

•Warning messages are indicated as:

Warning message

WARNING

•Important notes are indicated as:

Note details

NOTE

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1.0INTRODUCTION

1.1General Description and Features

The WRM-10P is designed to accurately measure the winding resistance of highly inductive power transformers. The unit’s dual resistance-reading input channels can measure two winding resistances simultaneously, and four-wire (Kelvin) connections provide high accuracy and require no lead compensation. The WRM-10P provides stable resistance readings of very large transformers by utilizing a 36 Vdc power supply capable of outputting up to 10 Amperes. The resistance reading of a 100MVA transformer can be achieved in 5 minutes or less. The unit’s power supply is cooled by heavy-duty fans designed for continuous operation. For greater flexibility in the field, the WRM-10P comes with a built-in 2.5-inch wide thermal printer used for printing test reports.

Since the WRM-10P can accurately measure resistances ranging from 1 micro-ohm to 2,000 ohms, it can also be used to measure EHV circuit-breaker contact resistance, motor winding resistance, or any low resistance. If the transformer winding temperature is entered, the WRM10P can calculate the equivalent resistance value of the winding material (aluminum or copper) at any standard reference temperature. Also, a special test mode can run a test for up to 45 minutes while saving resistance readings at one-minute intervals. In addition to measuring the resistance value, the WRM-10P also checks the “make-before-break” tap-switching sequences of voltage regulators and load tap changers.

The WRM-10P can store test results in Flash EEPROM. Test results can be printed on the built-in 2.5-inch wide thermal printer or can be transferred to a PC via the RS-232C interface port.

The WRM-40 has all the features of the WRM-10P, but is capable of outputting up to 40 Amperes. The WRM-10P has a resistance reading range of 1 micro-ohm to 2,000 ohms while the WRM-40 has a resistance reading range of 1 micro-ohm to 500 ohms.

The WRM-10P and WRM-40 come furnished with three 50-foot test cables. Each test cable lead is terminated with a quick-disconnect test clip.

Built-in Safety Features

At the end of each test, the WRM automatically dissipates the stored energy in the transformer. This discharge circuit will continue to work even if the supply voltage is lost. For added safety, the unit’s power supply is thermally protected from over-load damage.

User Interface

The WRM features a back-lit LCD screen (20 characters by 4 lines) that is viewable in both bright sunlight and low-light levels. A rugged, alpha-numeric, membrane keypad is used to control the unit.

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Internal Test Record Storage

The WRM can store 63 test records (up to 48 readings per test record) in Flash EEPROM. Test records can be retrieved and printed on the built-in thermal printer or can be transferred to a PC via the RS-232C interface port. A Windows® XP/Vista-based software application is provided with each WRM. This software can be used to retrieve test records from the WRM and can also be used to export records in Microsoft® Excel format.

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1.2Technical Specifications

1.2.1. WRM-10P Technical Specifications

Table 1. WRM-10P Technical Specifications

TYPE	Portable transformer winding resistance meter
PHYSICAL SPECIFICATIONS	16.8”W x 12.6”H x 10.6”D (42.6 cm x 32.0 cm x 26.9 cm); Weight: 27 lbs
	(12.2 kg)
INPUT POWER	100 – 120 Vac or 200 – 240 Vac (factory pre-set), 50/60 Hz
	(Please see the voltage setting notes in section 2.1)
RESISTANCE READING	1 micro-ohm – 2,000 ohms
RANGE
ACCURACY	1 – 19,999 micro-ohms: ±0.5% reading, ±1 count;
	20 – 999 milliohms: ±1% reading, ±1 count;
	1 – 2,000 ohms: ±1.5% reading, ±1 count
TEST VOLTAGE	36 Vdc max
TEST CURRENT RANGE	Auto range, 10 Amperes max
DISPLAY	Back-lit LCD Screen (20 characters by 4 lines); viewable in bright sunlight
	and low-light levels
PRINTER	2.5-inch wide built-in thermal printer
KEYPAD	Rugged membrane keypad (10 alpha-numeric keys, 6 function keys)
INTERNAL TEST RECORD	Stores 63 test records of 48 readings each
STORAGE
COMPUTER INTERFACE	One RS-232C (19,200 Baud) port
PC SOFTWARE	Windows® XP/Vista-based software is included with purchase price
SAFETY	Designed to meet IEC61010 (1995), UL61010A-1, CSA-C22.2 standards
ENVIRONMENT	Operating: -10˚C to 50˚ C (15˚F to +122˚ F); Storage: -30˚ C to 70˚ C (-
	22˚F to +158˚ F)
CABLES	Three 50-foot test cables, ground cable, power cord and cable bag
OPTIONS	Transportation case
WARRANTY	One year on parts and labor

The above specifications are valid at nominal operating voltage and at a temperature of 25°C (77°F). Specifications may change without prior notice.

NOTE

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1.2.2. WRM-40 Technical Specifications

Table 2. WRM-40 Technical Specifications

TYPE	Portable transformer winding resistance meter
PHYSICAL SPECIFICATIONS	25”W x 8.5”H x 20”D (63.5 cm x 21.6 cm x 50 cm); Weight: 44 lbs (20 kg)
INPUT POWER	100 – 120 Vac or 200 – 240 Vac (factory pre-set), 50/60 Hz
	(Please see the voltage setting notes in section 2.1)
RESISTANCE READING	1 micro-ohm – 500 ohms
RANGE
ACCURACY	1 – 19,999 micro-ohms: ±0.5% reading, ±1 count;
	20 – 999 milliohms: ±1% reading, ±1 count;
	1 – 500 ohms: ±1.5% reading, ±1 count
TEST VOLTAGE	36 Vdc max
TEST CURRENT RANGE	Auto range, 40 Amperes max
DISPLAY	Back-lit LCD Screen (20 characters by 4 lines); viewable in bright sunlight
	and low-light levels
PRINTER	2.5-inch wide built-in thermal printer
KEYPAD	Rugged membrane keypad (10 alpha-numeric keys, 6 function keys)
INTERNAL TEST RECORD	Stores 63 test records of 48 readings each
STORAGE
COMPUTER INTERFACE	One RS-232C (19,200 Baud) port
PC SOFTWARE	Windows® XP/Vista-based software is included with purchase price
SAFETY	Designed to meet IEC61010 (1995), UL61010A-1, CSA-C22.2 standards
ENVIRONMENT	Operating: -10˚C to 50˚ C (15˚F to +122˚ F); Storage: -30˚ C to 70˚ C (-
	22˚F to +158˚ F)
CABLES	Three 50-foot test cables, ground cable, power cord and cable bag
OPTIONS	Transportation case
WARRANTY	One year on parts and labor

The above specifications are valid at nominal operating voltage and at a temperature of 25°C (77°F). Specifications may change without prior notice.

NOTE

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1.3WRM Controls and Indicators

The WRM-10P and WRM-40’s controls and indicators are shown in Figure 1 and Figure 2, respectively. A leader line with an index number points to each control and indicator, which is cross-referenced to a functional description in Table 3 for the WRM-10P and Table 4 for the WRM-40. The tables describe the function of each item on the control panel. The purpose of the controls and indicators may seem obvious, but users should become familiar with them before using the WRM. Accidental misuse of the controls will usually cause no serious harm. Users should also be familiar with the safety summary found on the front page of this User’s Manual.

Figure 1. WRM-10P Controls and Indicators

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Table 3. Functional Descriptions of WRM-10P Controls and Indicators

Item	Panel Markings	Functional Description
Number

1V1

2V2

3CURRENT

4

Voltage sensing channel #1. Female test connector jacks for connecting voltage-sensing test leads.

Voltage sensing channel #2. Female test connector jacks for connecting voltage-sensing test leads.

Current Output. Female test connector jacks for connecting current test leads.

Back-lit LCD screen (4 lines by 20 characters). Visible in bright light and lowlight conditions.

9-pin RS-232C interface port; female DB type. Data rate is set to 19,200 baud, 1 start bit, 2 stop bits, 8 data bits and no parity bit.

				Pin	Signal
5		RS-232C		2	RX
				3	TX
				5	Signal Ground

240 Vac 2A,

650-60 Hz Fuse: 250 Vac, 3A Slow Blow

7GROUND

8

9 DISCHARGE

Input power connector with third-wire safety ground. On/Off rocker toggle switch with built-in fuse protection.

Safety ground. This must be connected to station ground before connected the WRM test leads to the transformer.

Built-in 2.5-inch wide thermal printer.

Red LED warning indicator light. This LED is illuminated when the WRM is discharging the stored energy from the transformer. Do NOT disconnect test leads when this light is on. Failure to heed this warning can result in shock to personnel.

10					Rugged membrane keypad.
	11		HIGH VOLTAGE		Red LED warning indicator light. This LED is illuminated when there is a
			PRESENT		possibility that voltage exists across the test leads.

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Figure 2. WRM-40 Controls and Indicators

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Table 4. Functional Descriptions of WRM-40 Controls and Indicators

Item	Panel Markings	Functional Description
Number

1V1

2V2

3CURRENT

4

240 Vac 2A,

5 50-60 Hz

Fuse: 250 Vac,

3A Slow Blow

Voltage sensing channel #1. Female test connector jacks for connecting voltage-sensing test leads.

Voltage sensing channel #2. Female test connector jacks for connecting voltage-sensing test leads.

Current Output. Female test connector jacks for connecting current test leads.

Air intake cooling fans. The air intake cooling fans maintain the internal temperature. There is an output air fan on the side of the case.

Input power connector with third-wire safety ground. On/Off rocker toggle switch with built-in fuse protection.

6GROUND

7

8RS-232C

9DISCHARGE

Safety ground. This must be connected to station ground before connected the WRM test leads to the transformer.

Built-in 2.5-inch wide thermal printer.

9-pin RS-232C interface port; female DB type. Data rate is set to 19,200 baud, 1 start bit, 2 stop bits, 8 data bits and no parity bit.

Pin	Signal
2	RX
3	TX
5	Signal Ground

Red LED warning indicator light. This LED is illuminated when the WRM is discharging the stored energy from the transformer. Do NOT disconnect test leads when this light is on. Failure to heed this warning can result in shock to personnel.

10					Rugged membrane keypad.
	11		HIGH VOLTAGE		Red LED warning indicator light. This LED is illuminated when there is a
			PRESENT		possibility that voltage exists across the test leads.

					Back-lit LCD screen (4 lines by 20 characters). Visible in bright light and low-
	12
					light conditions.

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2.0PRE-TEST SETUP

2.1Operating Voltages

The WRM’s operating voltage is preset at the factory and is selectable between 100-120 Vac, 50/60 Hz or 200-240 Vac, 50/60 Hz. The voltage is set by placing jumper(s) on the power terminal block as listed in Table 5 and illustrated in Figure 3 and Figure 4. The relay must also be changed if the voltage settings are changed. Please see Figure 5 and Figure 6 for the location of the relays.

Table 5. Voltage Selection Jumper Settings

	Voltage		Terminal Block Jumpers		Relay
	Selection				Part Number
	100 – 120 Vac		Brown to Blue and Yellow to Green		HE2aN-Q-AC120V
	200 – 240 Vac		Blue to Yellow		HE2aN-Q-AC-240V

Figure 3. 100 – 120 Vac Jumper Settings

Figure 4. 200 – 240 Vac Jumper Settings

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Figure 5. WRM-10P Relay Location

Figure 6. WRM-40 Relay Location

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WRM-10P AND WRM-40 USER’S MANUAL REV 3

2.2LCD Screen Contrast Control

To increase the LCD screen contrast, press and hold the [PAPER Contrast] key for two seconds.

To decrease the LCD screen contrast, press and hold the [PAPER Contrast] key for two seconds.

2.3Printer Paper Control

To advance the WRM printer paper, press and release the [PAPER Contrast] key. To retract the WRM printer paper, press and release the [PAPER Contrast] key.

2.4Printer Paper

The WRM’s built-in thermal printer uses 2.5-inch wide thermal paper for printing test results. To maintain the highest print quality and to avoid paper jams, the use of thermal paper supplied by Vanguard Instruments Company is highly recommended. Additional paper can be ordered from the following sources:

Vanguard Instruments Co, Inc.

1520 S. Hellman Avenue Ontario, CA 91761

Tel: [phone]

Fax: [phone]

Part Number: VIC TP-3 paper

BG Instrument Co.

13607 E. Trent Avenue Spokane, WA 99216 Tel: [phone] Fax: [phone]

Part Number: VIC TP-3 paper

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2.5Replacing the Thermal Printer Paper

The roll of thermal paper is housed inside a dispenser underneath the printer cover. To replace the paper, follow the steps below:

•Unscrew the two large printer cover screws and remove the printer cover.

•Remove the leftover thermal paper roll from the paper holder.

•Unroll the new thermal paper roll.

•Feed the thermal paper into the slot between the paper pocket and the rubber roller. The printer will automatically pull the paper under the thermal head.

•Place the paper roll into the paper holder.

•Lift the thermal head and align the thermal paper if necessary.

•Re-install the printer cover.

Thermal paper has a chemical coating on one side of the paper. This side should be facing the thermal print head. Incorrect paper loading may result in blank output on

the thermal paper.

NOTE

The thermal paper will show a red stripe to indicate that the roll is about to run out of paper.

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WRM-10P AND WRM-40 USER’S MANUAL REV 3

3.0OPERATING PROCEDURES

3.1WRM Cable Connections

Typical WRM connection diagrams are shown in Figure 7, Figure 8, Figure 9, and Figure 10.

•Do not touch or disconnect any test lead that is connected to a transformer terminal while high current is being conducted during a test. Failure to heed

WARNINGS	this warning can result in lethal electric shock to personnel and/or damage
	to the equipment.

•Disconnect the test clips from the transformer bushing only after the WRM has completely discharged the transformer. Always disconnect the test clips slowly from the transformer bushing to prevent an accidental flash-over.

Figure 7. Typical WRM Connections Diagram #1

Figure 8. Typical WRM Connections Diagram #2

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Figure 9. Typical WRM Connections Diagram #3

The above figure illustrates the simultaneous testing of both the high and low windings on a single-phase transformer. When measuring two channels, the above

NOTE cable connection is recommended since it will speed up the testing process.

Figure 10. Typical WRM Connections Diagram #4

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