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Vanguard TRM-403 – For Any Low Resistance Measuring Application

vanguard_trm_-403-01For a Delta transformer, the Vanguard TRM-403 Transformer Resistance Meter can measure the phase resistance readings and provide the individual Delta winding resistance values. The Vanguard TRM-403 can also provide the individual winding resistance values for a Wye transformer without the neutral terminal.

Since the Vanguard TRM-403 can accurately measure resistance from 1 micro-ohm to 500 Ohms, it can be used as a micro-ohm meter to measure EHV circuit breaker contact resistance, or for any low resistance measuring application.



Vanguard TRM-403 Specifications:


Portable transformer winding resistance meter

Physical Specifications

21”W x 17”H x 9” D (53 cm x 43 cm x 24 cm)

Weight: 35 lbs (15.8 kg)

Operating Voltage

100 ¬ 240 vac, 50/60 hz

Resistance Reading Range

1 micro-ohm ¬ 500 ohms


1 ¬ 19,999 micro-ohms: ±0.5% reading, ±1 count

20 ¬ 999 milli-ohms: ±1% reading, ±1 count

1 ¬ 2000 ohms: ±1.5% reading, ±1 count

Test Current

1A ¬ 40A in 1A increments

Test Voltage

60Vdc charging, 18V DC max during measurement

Input Channels

4 input channels for measuring resistance


Back-lit LCD Screen (240 x 128 pixels)

Viewable in bright sunlight and lowlight levels


Built-in 2.5-inch wide thermal printer

Internal Data Storage

256 static test records (each can contain up to 111 readings) and 120 dynamic test records

External Data Storage

Up to 999 test records on external USB Flash drive

Computer Interfaces

RS-232C, USB, and Bluetooth


Designed to meet UL 61010A-1 and CAN/CSA C22.2 No. 1010.1-92 standards


Operating: -10°C to +50°C (+15°F to +122°F); Storage: -30°C to +70°C (-22°F to +158°F)


90% RH @ 40°C (104°F) non-condensing


2,000 m (6,562 ft) to full safety specifications

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