Low voltage reading

[mickeyrench]

Can someone tell me why my 1587 fluke megger when megging at 1000v on a pump motor the voltage never shows up om the meter at the normal 1050v reading, it comes up with a low voltage. The meter only comes up with that reading on this one large motor and it has a very low meg reading, i checked the megger agaisnt a motor of the same hp and it meggs at a 1000v and shows up on the meter.

 

[zog]

Can someone tell me why my 1587 fluke megger when megging at 1000v on a pump motor the voltage never shows up om the meter at the normal 1050v reading, it comes up with a low voltage. The meter only comes up with that reading on this one large motor and it has a very low meg reading, i checked the megger agaisnt a motor of the same hp and it meggs at a 1000v and shows up on the meter.

The high leakage current on your motor with the bad R readings wont allow the little 1587 to charge the windings, yore meter dosent have the "Oomph" to maintain 1000V. A larger megger might be able to maintain 1000V. A highpot would for sure.

But I have to ask, why do you care? Just curious I hope.

 

[mickeyrench]

I am not that knowlegeable on megging and I'm trying to find out the condition of the motor. That meter gets up to its max reading of 2.2g without a problem on a same size motor and i want to be sure that there is a bad motor down there. The chief has been on vacation and the manager of the dept. where this motor is said there isn't anything wrong with the pump/motor and won't pull it up. I want to be sure I am making the right decision. This is why I care. Thanks for your help with this.

 

[zog]

I am not that knowlegeable on megging and I'm trying to find out the condition of the motor. That meter gets up to its max reading of 2.2g without a problem on a same size motor and i want to be sure that there is a bad motor down there. The chief has been on vacation and the manager of the dept. where this motor is said there isn't anything wrong with the pump/motor and won't pull it up. I want to be sure I am making the right decision. This is why I care. Thanks for your help with this.

I didn't mean why do you care about the motor or the readings, just why you cared about the test voltage being low on a bad motor.

This motor is underwater right? Are you able to disconnect the motor from the cables? From what you have described (I assume this comes from the other thread) you have done what you can and your results are below any spec, thats really all you can do. Keep in mind that the manager may only care that the motor is running and in his eyes there is not anything wrong with it becasue it is running. When it fails (it will), you get to do that "I told you so" smile as that same manager freaks out because his production line is down. Have a spare located before hand and you get to be the hero.

 

[mickeyrench]

understood. Thanks again for all your help with this.