Transformer Winding Resistance Meter is designed to measure the winding resistance of transformers, Inductors, generators and motor windings, Tap Changers, Bus Bar contacts,Power Cables etc


It is specially designed for Highly Inductive objects like 765kV/400kV/220kV. This is only indigenous TWRM which gives very fast readings for 3Phase Star -Delta any combination Transformers. The built in open circuit Features Voltage of DC Supply ensures that core of the transformer is saturated for fast measurements to be taken.Care is taken to absorb the Back emf of such transformers. For user safety, Indication for discharge is provided on front panel,if the current through winding under measurement is disturbed/discontinued.


Instrument has built in 10A regulated and highly stable specifical current surce with current seletion of 10A,5A,1A,0.1A Power supply 100mA & 10mA Instrument uses ratio -metric circuit where the resistance of specimen is compared with known internal standard and 4 1/2 digit LCD display is provided for resistance measurement in microohm, milliohms and in ohms.


Tap changers time and graph OLTC time and current deviation in% Heat run graph test time Vs resistance.

  • 1. Regulated and highly stable 50V.25Amp, 10A, 5A, 1A, 0.1A & 0.01A current source.

  • 2. 4½ digit LCD display , 19999 counts.

  • 3. Simultaneous measurements of voltage & current.

  • 4. True four terminal measurement.

  • 5. Resolution of 0.1 micro ohm.

  • 6. Protection against inductive kickback and discharge.

  • 7. Resistance Range Auto ranging

  • 8. Visual Indication For discharge.

  • 9. Line voltage interference suppression making instrument most suitable for field application.

  • 10. Automatic Discharge.

  • 11. Thermally Protected Power Supply.

  • 12. Light weight carrying case & with 15 meter leads.

  • 1. POWER SUPPLY : 230V AC ±10%,50Hz ±5%, single phase.

  • 2. TEST CURRENT : 10A,5A,1A,25A,10mA,100mA.

  • 3. RESISTANCE RANGE : 0.1m‎Ω to 1.9999kΩ ( Auto Ranging )

  • 4. INDICATION : 4 LINE LCD ( 19999 counts)

  • 5. RESOLUTION : 0.1μΩ at 1.9999milliohm.

  • 6. ACCURACY : ± 0.5% FSD

  • 7. DC POWER SUPPLY 50VDC, 25Amp

  • 8. KEYPAD : 12 Keys Soft-touch.

  • 9. CABLES : Test cables 20mtr ,Ground Cable, Power Chord & Cable Bag.

  • 10. SAFETY SPECS : Complied IEC61010

  • 11. EMI/EMC SPECS : Complied IEC61326

  • 12. WEIGHT : < 20Kg( Without Leads )

  • 13. OPERATING TEMP : 0°C to +50°C

  • 14. OPERATING HUMIDITY : Max 90% NonCondensing

  • 15. CHANNELS : 2 Channels.

  • 16. PORTS : RS 232 Port

  • 17. DIMENSIONS 520 x 420 x 230 mm

Transformer Winding Resistance Meter Model :25A

Transformer Winding Resistance Meter