Why Winding Resistance Test is Important for the Motor?

Why the Winding Resistance Test is Important for the Motor

Winding resistance test measurements detect various faults in motors and transformers: shorted turns, loose connections, broken strands, and malfunctioning tap changer mechanisms.

Studies conducted by IEEE and the Electric Power Research Institute (EPRI) on electric rotating machinery failures show that 48% of motor failures are due to electrical failures.

Winding resistance test measurements detect problems in motors that other tests may not find.

These problems include:

1. Partial or fully shorted coils.

2. Poor crimps or connections.

3. Imbalance between phases (improper turns on phases) and incorrect coil (phasing) connections.

Winding resistance testing method:

Winding resistance tests are a measurement of the applied DC voltage and current to the device under test – DUT. Using Ohm’s law the resistance is calculated in µΩ (micro Ohms) or mΩ (milli Ohms) by the winding analyzer.

Visualization ohm's law
Visualization of ohm’s law

For a 3-phase motor, 3 resistance measurements are normally done between the phases, and the balance or imbalance between the 3 measurements is calculated and displayed along with the measurement values.

For single coils and sometimes for motors, the resistances measured may be compared to a resistance value instead of having a balance calculated. The difference in percent to the target resistance value is then calculated.

A temperature correction factor can automatically be applied to correct the measurement to a standard temperature so results can be more accurately tracked over time with the winding analyzer.

source: electrominst.com

Aarohi Winding Resistance Test Meter

AAROHI  resistance meter measure a wide range of resistance values at a high level of accuracy.

RR2204CZZ  is a high-precision, portable resistance meter capable of measuring resistance with extremely high accuracy with low ambient temp. effect.

Resistance Meter
Aarohi Winding Resistance test meter

This is ideal for the testing and maintenance of

  • Electric motors,
  • Pump sets & other equipment with windings.

This Instrument is based on the Kelvin 4- wire connection method for the measurement of low resistance.

To know more about instrument visit : https://www.aarohies.com/service/resistance-meter

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