¶ Tools needed
Multimeter with ohm reading
set the scale on ohm like in the picture
¶ Check correct operation of multimeter
Cross the probes you should get a reading of 0 Ω (ohm), when probes are not crossed you should get O.L (open loop)
If this is true the volt meter can be used to test motor, if not get a new multimeter
¶ Check Y or Δ
Check if your motor is connected in Y or Δ (delta) and take a note of it.
¶ Check each phase to ground
With one probe on the motor frame, test with the other probe each phase U1, V1, W1, none of them should give a 0 Ω (ohm) reading, all of them should read O.L (open loop), if any of the phases terminals have a Ω (ohm) reading the winding is shorted to ground and needs to be rewind.
¶ Check phase to phase with plates still on
With the motor cables still secured and all the plates in place but without power.
Test with one probe on U1 and one on V1 and take note of reading.
Test with one probe on U1 and one on W1 and take note of reading.
Test with one probe on V1 and one on W1 and take note of reading.
If the Ω (ohm) reading differs for more than +-10% or you read 0 Ω (ohm) the motor windings are compromised
¶ Check phase to phase with plates off
Remove nuts and plates to free the cables, make sure you marked whether it was mounted Y or Δ (delta)
Test with one probe on U1 and one on U2 and take note of reading.
Test with one probe on V1 and one on V2 and take note of reading.
Test with one probe on V1 and one on W1 and take note of reading.
If the Ω (ohm) reading differs for more than +-10% or you read 0 Ω (ohm) the motor windings are compromised