The Vanguard WRM-40 Winding Resistance Ohmmeter 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-40 provides stable resistance readings of very large transformers by utilizing a 36Vdc power supply capable of outputting up to 40 Amperes. The resistance reading of a 500MVA transformer can be achieved in 5 minutes or less. The unit’s power supply is cooled by four heavy-duty fans designed for continuous operation. For greater flexibility in the field, the WRM-40 comes with a built-in 2.5-inch wide thermal printer used for printing test reports.
Vanguard WRM-40 Features
- Auto discharge circuit for operator safety
- Auto current ranging from 10 mA to 40 A
- Digital resistance reading from 1 microohm to 500 ohms
- Stores 63 records (of 48 readings each)
- Built-in 2.5-inch wide thermal printer
Vanguard WRM-40 Specs
- Type: portable transformer winding resistance meter
- Input Power: 100 – 120 Vac or 200 – 240 Vac (factory pre-set), 50/60 Hz
- Resistance Reading Range: 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 – 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 Storage: stores 63 test records of 48 readings each
- Computer Interface: one RS-232C port
- PC Software: Windows®-based software is included with purchase price
- Safety: designed to meet IEC61010 (1995), UL61010A-1, CSA-C22.2 standards
- Cables: three 50-foot test cables, ground cable, power cord and cable bag