Winding resistance meters ATRM-20/ATRM-40

The ATRM-20 and ATRM-40 are Amperis’ third generation transformer winding resistance meters. The ATRM line is designed specifically to measure DC resistance values of transformer windings, rotating machine windings, or any dc resistance of an inductive device. The ATRM line features dual resistance-reading input channels that can measure two winding resistances simultaneously (primary and secondary windings of a transformer).

Both the ATRM-20 and ATRM-40 can provide a fast and stable reading of very large transformers by utilizing a 60Vdc power supply. The ATRM-20 is capable of outputting a selectable test current from 1A to 20A while the ATRM-40’s test current is selectable from 1A to 40A.

Specifications

• Computer Interface

The ATRM can be connected to a PC via the unit’s RS-232C, USB, or Bluetooth interface. The included Windows®-based Transformer Winding Resistance Analyzer (TWRA) software can be used to retrieve test records (stored in the ATRM or on a USB Flash drive) or to run tests from the PC. Test records are automatically
exported to PDF, Excel, and XML formats.

• User Interface

The ATRM features a back-lit graphic LCD screen (128 x 64 pixels) that is clearly viewable in both bright sunlight and low-light levels. An alphanumeric keypad is used to enter test information and to operate the unit.

• Safety Features

The ATRM automatically dissipates the energy stored in the transformer at the end of each test The discharge circuit will continue to work even if the ATRM power supply is lost.

• Test Record Storage

The ATRM can store up to 256 static test records (111 readings per record) and 120 dynamic test records internally. For external test record storage, the ATRM features a USB Flash drive interface port. Up to 999 test records can be stored on a connected USB Flash drive.

ATRM-20/40 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 (15.4 kg)
Operating voltage	100 - 240 Vac, 50/60 Hz
Resistance reading range	ATRM-20: 1 micro-ohm - 2000 ohms; ATRM-40: 1 micro-ohm - 500 ohms
Accuracy	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	ATRM-20: 1A ¬ 20A in 1A increments; ATRM-40: 1A ¬ 40A in 1A increments
Test voltage	60Vdc charging, 18V DC max during measurement
Resistance channels	Two static resistance reading channels
Display	Back-lit LCD screen (128 x 64 pixels); viewable in bright sunlight and low light conditions
Printer	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 interface	RS-232C, USB, and Bluetooth
Safety	Designed to meet UL 61010A-1 and CAN/CSA C22.2 No. 1010.1-92 standards
Environment	Operating: -10°C to +50°C (+15°F to +122°F); Storage: -30°C to +70°C (-22°F to +158°F)
Humidity	90% RH @ 40°C (104°F) non-condensing
Altitude	2,000 m (6,562 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
Optional accessories	Transportation case
Warranty	1 year on parts and labor

NOTE: the above specifications are valid at nominal voltage and ambient temperature of +25°C (+77°F). Specifications are subject to change without notice