test for after high heat motor 1

[martense]

hi everyone,
i have a motor 3 kv 125 kw, the motor was place in a room and the room accidently was on fire. after the fire, we have checked for the winding insullation resistance and the result was 2500 MegOhm, my question is what next step do i must do next to ensure the motor is still ok to operate maybe other test?, because visualy the motor especially the overhang is not too good and i'm not to sure that winding insullation test result only is enough to conclude that the motor is still ok.

thank you,

best regards,

Marten

 

[edison123]

Looks like the end windings are seared by the heat. You are right. IR is not enough. Suggest that you avail the services of of a good local rewind company to assess the usability.

Left to myself, I would rewind the motor but then I am biased.

Muthu

http://www.edison.co.in

 

[martense]

Dear Mr. Muthu,
i'm planning to do hipot test and surge test,
need your oppinion on this

thank you,

regards,
Marten

 

[edison123]

Hi Marten

Yes, they are good tests to assess the winding condition but are potentially destructive tests too. So, you must be prepared for that fail.

If you have all the 6 leads of the 3 phases brought out, then a hipot on one phase with other two phases grounded, will check both the ground insulation and the phase to phase insulation. If you have only 3 leads brought out (with an internal or even external neutral point), then hipot checks only the ground insulation. My suspicion is that the damage is more in end windings and would likely result in phase to phase failure in that zone if put in operation.

Don't forget to measure the winding PI before the hipot.

Good luck and please call me Muthu. Mr. makes me feel my age.

Muthu

http://www.edison.co.in

 

[martense]

Muthu,
thank you very much for your opinion,
if we do the PI first and the result was not good , can we proceed to hipot test?because in my aware the PI value can be bad because of dirt in insullation?

thank you,

regards,

Marten

 

[edison123]

Marten

Yes, A bad indicates moisture (which in your case is doubtful or contamination, which may be due to the seared insulation.

If the PI is bad, I suggest that you don't do the hipot/surge.

Muthu

http://www.edison.co.in

 

[martense]

Muthu,
thank you very much.

best regards,

Marten