megging

[puckman]

I meg a 250 hp 480v motor used with a vfd and was wondering if my fluke 1578 is ok for the task. I got 2.2. gigs which is as high as the meter goes. I seem to get a lot of 2.2 readings and wanted to ask if I am megging right.
I disconnect the motor leads from the starter / or motor head and attach one to to the fluke lead and the other lead from the fluke to ground from the motor. The motor leads were 15' from the starter. A lot of the motors are 50, 85 ,100 hp motor / pumps that we meg.
I meg for a minute at a time on each of the three leads.
Thanks

 

[Fulthrotl]

I meg a 250 hp 480v motor used with a vfd and was wondering if my fluke 1578 is ok for the task. I got 2.2. gigs which is as high as the meter goes. I seem to get a lot of 2.2 readings and wanted to ask if I am megging right.
I disconnect the motor leads from the starter / or motor head and attach one to to the fluke lead and the other lead from the fluke to ground from the motor. The motor leads were 15' from the starter. A lot of the motors are 50, 85 ,100 hp motor / pumps that we meg.
I meg for a minute at a time on each of the three leads.
Thanks

seems reasonable, if you are using the 1000v scale, and to get 2.2 gigohms,
you need to set if for 1000v. that pretty common with a healthy motor.

for what it's worth, hooking to any one of the motor leads, to ground, tests
all of them, in a Y motor...