The TRM-20 is Vanguard Instruments’ third generation transformer winding resistance meter. The TRM-20 is designed specifically to measure DC resistance values of transformer windings, rotating machine windings, or any dc resistance of an inductive device.

The TRM-20 features dual resistance-reading input channels that can measure two winding resistances simultaneously (primary and secondary windings of a transformer). It can provide a fast and stable reading of very large transformers by utilizing a 60Vdc power supply. The TRM-20 is capable of outputting a selectable test current from 1A to 25A.

Since the TRM-20 can accurately measure resistance values from 1 micro-ohm to 2,000 Ohms, it can be used as micro-ohm meters to measure EHV circuit breaker contact resistance, or for any low resistance measuring application. The TRM-20 can automatically demagnetize the inductive device under test, eliminating the manual task of demagnetizing the transformer core after a resistance test.

• Auto-discharge circuit for operator safety
• Demagnetizes transformer after test
• Selectable test current from 1A to 25A
• RS-232C, USB, and Bluetooth computer interfaces
• Built-in thermal printer

TRM-20	Cables
Cable Part Number [8000-0005] USB Cable [ 6' (1.83m) ] 8000-0005 [8000-0006] RS-232C Cable [ 6' (1.83m) ] 8000-0006 [8000-0015] LTC Control Cable [ 15' (4.57m) ] 8000-0015 [8000-0016] Power + Ground Combination Cable 8000-0016 [8000-0071] Current and Sense Cable (Positive) [ 50' (15.24m) ] 8000-0071 [8000-0083] V2 Sense Cable [ 50' (15.24m) ] 8000-0083 [8000-0087] V1 Sense Cable [ 50' (15.24m) ] 8000-0087 [8000-0148] Current and Sense Cable (Negative) [ 50' (15.24m) ] 8000-0148

TRM-20	Technical Specifications
TYPE Portable transformer winding resistance meter PHYSICAL SPECIFICATIONS 21” W x 17” H x 9” D (53 cm x 43 cm x 24 cm); Weight: 33 lbs (15.4Kg) OPERATING VOLTAGE 100 – 240 Vac, 50/60 Hz RESISTANCE READING RANGE 1 micro-ohm to 500 Ohms ACCURACY 1 – 19,999 micro-ohms: ±0.5% reading, ±1 count 20 – 999 milliohms: ±1% reading, ±1 count 1 -2000 Ohms: ±1.5% reading, ±1 count TEST CURRENT 1-25A in 1A increments TEST VOLTAGE 60 Vdc charging, 18V DC max during measurement RESISTANCE CHANNELS Two static resistance reading channels DISPLAY Back-lit LCD (64 x 128 dot graphic), viewable in direct sunlight and low light levels PRINTER Built-in 2.5" 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, Bluetooth SAFETY Designed to meet UL 61010A-1 and Can/CSA C22.2 No 1010.1092 standards ENVIRONMENT Operating: -10oC to 50oC (15oF to +122oF) Storage: (-30oC to 70oC (-22oF to +158oF) HUMIDITY (MAX) 90% RH @ 40? C (104? F) non-condensing ALTITUDE (MAX) 2000m (6562 ft) to full safety specifications CABLES One 50-foot current cable set, two 50-foot resistance sense cable set, One LTC control cable, One ground cable, one power cord, One RS-232C cable, one USB cable OPTIONS Transportation Case WARRANTY One year on parts and labor Specifications are valid at nominal voltage and ambient temperature of +25?C (+77?F).