Electric Motor Winding Imbalance testing
Electric Motor Winding Imbalance testing
(OP)
I have a maintenance question to ask of all my learned colleagues out there.
Is it worthwile to perform Predictive Winding Imbalance testing on Low Voltage motors on a set frequency?
No online systems installed. Specific motors: 280kW, 380 V. Monitoring will be by shutting down the motor, isolating it and then measuring the winding resistances, possibly using a ductor.
Cheers
Is it worthwile to perform Predictive Winding Imbalance testing on Low Voltage motors on a set frequency?
No online systems installed. Specific motors: 280kW, 380 V. Monitoring will be by shutting down the motor, isolating it and then measuring the winding resistances, possibly using a ductor.
Cheers





RE: Electric Motor Winding Imbalance testing
Muthu
www.edison.co.in
RE: Electric Motor Winding Imbalance testing
It is a specialized test that requires some expertise to perform and interpret, also potentially destructive (so don't test unless you have a sparet on time).
For the above reason, a typical practice for field test centers around megger testing and various other "easier" tests that include winding resistance balance, and if you buy a box it may have inductive imbalance, capacitance measurements etc. I said typical practice - I didn't say it was smart... open to discussion.
I'm not sure if a ductor is a good device for winding resistance testing because there are some issues with building up the current and interrupting the current in an inductive circuit. Kelvin or similar bridge test is typically used for this purpose and bridge is incorporated into the motor testers like pdma, bjm etc.
=====================================
Eng-tips forums: The best place on the web for engineering discussions.
RE: Electric Motor Winding Imbalance testing
Also running amps and volts can help.
I agree with electricpete, a ductor/welder tripping or disconnecting will cause a large inductive voltage from the di/dt break. It's similar to a surge application.
Also insulation resistance testing likely won't pick up the imbalance. IR will detect polarization/leakage currents of your insulation system.