Electrical – How to check if a 3 phase motor is shorted or has problems


How can I test using an analog multimeter if this 3 phase motor is shorted? It has a hard time starting( turn a little then hums) if there is a load connected, but if you remove the load (removing the belt from the pulley), it will start turning. My multimeter has X10k, x1K, X100, X10, & X1.

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Best Answer

Fist make sure that the three-phase power voltages supplied to the motor are the proper voltage and balanced.

Check the resistance U1 to V1, V1 to W1 and W1 to U1. The resistances should be very close to being equal. Do the same for U2, V2 and W2. You should not find continuity between the groups (U1, V1 and W1) and (U2, V2 and W2).