How we meager an electrical motor to check Grounding?

Question

How we meager an electrical motor to check Grounding?

Answer 1

You might mean megger testing of electric motors.Tp megger test 440 volt motors, use a 1000vdc megger tester. Megger testers may be hand cranked or battery operated.

To megger test a motor, switch off the motor circuit breaker. Check for ground continuity between a motor grounding wire and the motor frame, preferably at the terminal box bolt hole. Hand crank the megger tester with its terminal probes connected to motor frame and ground wire. The reading should indicate zero ohms. Then, transfer one terminal probe to one motor terminal. Hand crank for one minute. The insulation resistance indicated in the scale should be 2 meg-ohms. However, in many instances, motors are run at 1 meg-ohm without winding heating.

Answer 2

you are beyond your abilities... call an electrician

3-phase motors.... there should be equal or very close resistance readings between all 3 legs... leg to leg

should be open or megohms from each leg to ground, one clip on the motor housing the other on the winding.... do you know how to read a megger? or what voltage to use on the megger? SHUT THE POWER OFF!!!

Answer 3

Either your question is mis worded or you are mistaken what meter to use.

You don't use a megger (high resistance meter) to test grounding. You use a ductor (low resistance).

If you asking how to check insulation resistance of a motor to ground then that's a little different.

To test insulation resistance, set the megger voltage to twice that of the operating voltage (1000v for 480v) and test between one phase and ground. There is no need to test every phase to ground as they will all be connected to each other anyway (wye or delta). The acceptable limit is subjective but my rule of thumb is better than 2MΩ for low voltage stuff.