motor test - Page 2 - Electrician Talk - Professional Electrical Contractors Forum

Lone Crapshooter · 06-04-2009, 07:48 PM

You are 100% correct. Someone started a rumor about megging each phase to ground IT IS NOT NECESSARY IF THE MOTOR IS MADE UP FOR A SPICIFIC VOLTAGE.
LC

MDShunk · 06-04-2009, 07:56 PM

Quote:

Originally Posted by mutabi

Lets say your first test A-B, B-C, A-C indicates (using a reg DMM), 0.2 Ohms phase to phase. Whats the point in megging each phase to ground? Wouldnt it make more sense to just meg say A to ground. If it is B that is shorted to ground wouldnt it show up while megging A since A and B are connected?

Yes, but if you had not ohmed it out first, you might be dealing with a motor with an open winding or with improperly made up connections. I just play it safe and meg each one to ground. Covers all the possible ways to screw up.

p_logix · 06-05-2009, 03:10 AM

Quote:

Originally Posted by MDShunk

Yes, but if you had not ohmed it out first, you might be dealing with a motor with an open winding or with improperly made up connections. I just play it safe and meg each one to ground. Covers all the possible ways to screw up.

Same here I meg all phases ground it takes 5 seconds longer to check.