20A Transformer DC Winding Resistance Tester

The HM5002-20A Three-Phase Transformer DC Resistance Tester integrates the auxiliary magnetization method, simultaneous testing of three-phase windings (Yn, Y, Δ), and an automatic demagnetization function. It is widely applicable for scenarios such as transformer factory testing, installation handover, and preventive testing. With a maximum output current of 40 A and a measurement range as wide as 25 kΩ, it meets a variety of testing needs, from distribution transformers to large-scale power transformers.

Output Current Single-phase mode: 40A, 20A, 10A, 5A, 1A, 0.2A, 10mA, <1mA

Three-phase mode: 20A+20A, 10A+10A, 5A+5A, 1A+1A, 0.2A+0.2A

Measurement Range Single-phase:

• 40A range: 0.1 mΩ to 0.5 Ω

• 20A range: 0.5 mΩ to 1 Ω

• 10A range: 1.0 mΩ to 2 Ω

• 5A range: 10 mΩ to 4 Ω

• 1A range: 0.1 Ω to 20 Ω

• 0.2A range: 1.0Ω to 100Ω

• 10mA range: 50Ω to 2kΩ

• <1mA range: 500Ω to 25kΩ

Three-phase:

• 20A+20A: 0.2mΩ to 0.3Ω

• 10A+10A: 0.5mΩ to 0.6Ω

• 5A + 5A: 10 mΩ to 1.5 Ω

• 1A + 1A: 0.1 Ω to 7.0 Ω

• 0.2A + 0.2A: 1.0 Ω to 30 Ω

Accuracy: ±(reading × 0.2% + 2 digits)

Power Supply: AC 220 V ± 10%, 50/60 Hz

Operating Temperature -10°C to +50°C

Relative Humidity <90%, non-condensing

Dimensions 428 mm × 350 mm × 230 mm

Net Weight Approx. 13.4 kg