Hi-Pot voltage levels for generator rotors

[Yuma]

Dear all;

What do you think are the adequate voltage levels for Hi-Pot testing a generator rotor during an overhaul? I have been checking IEEE, IEC and EPRI but can´t find any document where it states clearly the voltage levels (either AC or DC) for rotors during a maintenance.

Regards

 

[ScottyUK]

I would be very careful with a hi-pot on a generator rotor. I would not exceed the test voltage for a LV cable of similar voltage rating. For most large machines this would not be higher than 2.5kV, many small ones would not exceed 1kV. A true hi-pot is inviting problems.



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If we learn from our mistakes I'm getting a great education!

 

[edison123]

Agree with scotty. A hi-pot is a potentially destructive test and the equipment owner should be informed of this.

IEEE/IEC standards for ac hipot for new/rewound generator rotors 10 times the rotor voltage with a minimum of 1.5 KV and a maximum of 3.5 KV.

For an after-overhaul test, I would take to a maximum of 2 KV AC with the above caveat to the client.

* Women are like the police. They can have all the evidence in the world and yet they still want a confession - Chris Rock *

 

[rovineye]

Agree with the boys above. I would not Hi-Pot unless a new or overhauled machine.

I test isolated rotor at 1kV and the exciter/PMG windings at 500V.

 

[Zogzog]

AC or DC generator, induction or sync? Voltage?

All of thes elead you to a different reference and recommended hipot test voltage.