I test the motor winding resistance, the result of L1-L2 is 0.79 ohms, L2-L3 is 0.73ohms, L3-L1 is 0.68 ohms. My question is, does the winding resistance of the motor passed or failed? . .if failed, what is the reason?. .
Please provide more info: Motor size (HP or kW), voltage, new or used, rewound, sitting idle for long time or just removed from service, hot or cold, etc.
How did you test the resistance? If you just used a digital multimeter, you probably will not get accurate measurements because it cannot push enough current through any oxidation, etc., on the contact points. You should use a low-resistance ohmmeter (such as the Megger DLRO series), or alternatively you can use a DC power supply that can output 3-5 amps, measure the voltage drop with the DMM, and calculate R = V/I. Readings should be within about 1% of each other.
As for reason for failure, could be any of a number of things: turn-to-turn short, poor termination, damaged winding conductor... That can only be determined for sure by tearing it apart.
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Motor Winding Resistance
Re: Motor Winding Resistance
