WRM-10TM TRANSFORMER WINDING RESISTANCE METER USER’S MANUAL Vanguard Instruments Company, Inc. 1520 S. Hellman Ave.
WRM-10 USER’S MANUAL REV 2 SAFETY SUMMARY 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-10, 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-10.
REV 2 WRM-10 USER’S MANUAL TABLE OF CONTENTS CONVENTIONS USED IN THIS DOCUMENT ..................................................................................... 1 1.0 INTRODUCTION .................................................................................................................... 2 1.1 General Description and Features ................................................................................... 2 1.3 Technical Specifications .......................................................
WRM-10 USER’S MANUAL REV 2 CONVENTIONS USED IN THIS DOCUMENT This document uses the following conventions: • The WRM-10’s control knob is referenced as [CONTROL KNOB] • Menu names are referenced as “MENU NAME” • WRM-10 LCD screen output is shown as: MAIN MENU • Warning messages are indicated as: Warning message WARNING • Important notes are indicated as: Note details NOTE 1
REV 2 WRM-10 USER’S MANUAL 1.0 INTRODUCTION 1.1 General Description and Features The WRM-10 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. Four-wire (Kelvin) connections provide high accuracy voltage reading and require no lead compensation.
WRM-10 USER’S MANUAL 1.3 REV 2 Technical Specifications Table 1. WRM-10 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 27 cm); Weight: 27 lbs (12.2 kg) INPUT POWER 100 – 120 Vac or 200-240 Vac (factory pre-set), 50/60 Hz RESISTANCE READING 1 micro-ohm – 2,000 ohms RANGE ACCURACY 1 – 19,999 micro-ohms: ±0.5% reading, ±1 count 20 – 999 milli-ohms: ±1% reading, ±1 count; 1 – 2,000 ohms: ±1.
REV 2 1.4 WRM-10 USER’S MANUAL WRM-10 Controls and Indicators The WRM-10’s controls and indicators are shown in Figure 1 below. A leader line with an index number points to each control and indicator, which is cross-referenced to a functional description in Table 2. The table describes 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-10.
WRM-10 USER’S MANUAL REV 2 Table 2. Functional Descriptions of WRM-10 Controls and Indicators Item Number Panel Markings 1 V1 Voltage sensing input channel #1. Female connector jacks used for connecting voltage-sensing test leads. 2 I Current output. Female connector jacks used for connecting current test leads. 3 None Back-lit LCD screen (16 characters by 2 lines); viewable in bright sunlight and low-light levels. 4 GROUND Safety ground terminal.
REV 2 WRM-10 USER’S MANUAL 2.0 PRE-TEST SETUP 2.1 Operating Voltages The WRM-10’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 3 and illustrated in Figure 2 and Figure 3. The relay must also be changed if the voltage settings are changed. Please see Figure 4 for the location of the relay. Table 3.
WRM-10 USER’S MANUAL REV 2 Figure 4.
REV 2 2.2 WRM-10 USER’S MANUAL LCD Screen Contrast Control To adjust the LCD screen’s contrast: a. Start from the “MAIN MENU”: MAIN MENU Turn the [CONTROL KNOB] till the following screen is displayed: MAIN MENU Press the [CONTROL KNOB]. b. The following screen will be displayed: ADJ CONTRAST “PUSH” = DONE Turn the [CONTROL KNOB] clockwise to increase the contrast (darken the screen). Turn the [CONTROL KNOB] counter-clockwise to decrease the contrast (lighten the screen).
WRM-10 USER’S MANUAL 3.0 OPERATING PROCEDURES 3.1 WRM-10 Cable Connections REV 2 Typical WRM-10 connections diagrams are shown in Figure 5 and Figure 6. A typical dual winding connections diagram is shown in Figure 7. WARNING 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 this warning can result in lethal electric shock to personnel and/or damage to the equipment. Figure 5.
REV 2 WRM-10 USER’S MANUAL Figure 6. Typical WRM-10 Connections Diagram #2 NOTE 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 cable connection is recommended since it will speed up the testing process. Figure 7.
WRM-10 USER’S MANUAL 3.2 REV 2 General Procedures The main steps for using the WRM-10 are outlined below: a. Ground the WRM-10 to the substation ground. WARNING Always connect the WRM-10 to the substation ground before connecting any test lead to any transformer bushing. Failure to follow this procedure may damage the WRM-10. b. Plug the WRM-10 power cable into a power outlet. c. Insert current-cable plugs and voltage-sensing cable plugs into the corresponding control panel jacks. d.
REV 2 3.3 WRM-10 USER’S MANUAL Performing Transformer Tests 3.3.1. Performing a Single Resistance Test a. Start from the “MAIN MENU”: MAIN MENU Press the [CONTROL KNOB]. b. The following screen will be displayed: RUN TEST Turn the [CONTROL KNOB] till the following screen is displayed: RUN TEST Press the [CONTROL KNOB]. c. The following screen will be displayed: FLASH-OVER IF CABLES REMOVED! Press the [CONTROL KNOB]. d.
WRM-10 USER’S MANUAL REV 2 The WRM-10 will continue to apply the test voltage on the transformer’s windings and update the resistance values on the LCD screen. Press the [CONTROL KNOB] to stop the test. f. The WRM-10 will automatically discharge the transformer and display the following screen during the discharging process: DISCHARGE XFMR! PLEASE WAIT... After the transformer is discharged, the test results will be displayed on the screen as shown: R1 = 10.0 mΩ R2 = 10.5 mΩ Press the [CONTROL KNOB].
REV 2 WRM-10 USER’S MANUAL 3.3.2. Performing a Voltage Regulator Test The Voltage Regulator Test verifies that a regulating switch in a primary voltage tap regulator changes contacts through its selection range without a break in the circuit. This test is important because in actual use, any break in the current in a regulating tap switch generates large reactive voltage spikes that are hazardous and may exceed the switch’s voltage ratings, thus causing irreparable damage.
WRM-10 USER’S MANUAL REV 2 e. The following screen will be displayed while the test is being performed: *XFMR CHARGING* After the transformer has been charged, the following screen will be displayed: V REG. TEST RUN TAPS NOW Run the voltage regulator tap switch. f. If no transient is detected as the taps are switching: 1. The screen display will not change 2. Turn or press the [CONTROL KNOB] to end the test. The following screen will be displayed: NO TRANSIENT DETECTED If a switch break is detected: 1.
REV 2 3.4 WRM-10 USER’S MANUAL User Diagnostic Mode The user diagnostic mode can be used to monitor the V1 and V2 voltages and the test current on the WRM-10’s LCD screen. To use the WRM-10 in user diagnostic mode: a. Connect the WRM-10 to the test transformer, and then start from the “MAIN MENU”: MAIN MENU Turn the [CONTROL KNOB] till the following screen is displayed: MAIN MENU Press the [CONTROL KNOB]. b.
1520 S. Hellman Ave • Ontario, CA 91761 • USA Phone: 909-923-9390 • Fax: 909-923-9391 www.vanguard-instruments.com Copyright © 2009 by Vanguard Instruments Company, Inc. WRM-10 User’s Manual • Revision 2.
