How Do I Test an AC Motor? - TigerStop

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Motor should be removed from machine

Items Required:
Multimeter & AC Motor Cable Pinout document

Test One – Cogging:
Rotate motor by hand, it must turn freely with a small amount of cogging. The motor will not produce the required amount of power without cogging. If no cogging, then FAIL.

Test Two – Short:
Tie all 3 drive wires together and rotate the motor by hand. It should be hard to rotate. If not, FAIL.

Test Three – Voltage:
Set multimeter to measure DC voltage connected to M1 & M2, Rotating the motor by hand, should produce a voltage reading on the multimeter. If no voltage, FAIL. Repeat between all phases (M1 & M3, M2 & M3).

Test Four – Open:
Set multimeter to measure resistance Ω. Measure from each phase to motor case. If readings show
anything other than OL or infinate, then FAIL.

Test Five – Resistance:
Set multimeter to measure resistance Ω. Measure between all phases (M1 & M2, M1 & M3, M2 & M3)
Readings should be around 2-4 ohms. If not, then FAIL.