Checking and Testing of Exciter

[BoyNaruto]

Hi,

May I ask your technical advise as to how can I test if my exciter stator coil and exciter rotor is still in good shape? I took the resistance reading from the exciter stator and the reading is only 2.5ohms. I understand from my previous readings that normally the stator coil is around 10-11ohms??? Can this be the verdict?

By the way, during the troubleshooting, I changed the AVR and changed the rotating diodes , do some field flushing on the stator and the rotor of the exciter, but until now I don't have any output from the generator load side. I did some small test putting a 12V in my F+ and F- while the genset and I did get some readings on the load side. This leads me to the conclusion that my main windings are not burned after all.

This is the reason why I put my concentration on the exciter side. Thanks in advance for your support.

 

[waross]

What size set?
Do you have a megger?

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[BoyNaruto]

Hi Waross,

Yes I have, I measured the resistance of the exciter stator and its only 2.5ohms. I think I need to check it out with my megger, what could be the minimum allowable resistance?

Thanks,
Chris

 

[BoyNaruto]

Hi Warross and other professionals,

I've managed to check the insulation resistance on the exciter stator field and exciter rotor windings and the result is 0.12M on the stator and on the exciter rotor is only 0.02M.

The Main field is about 3-4M and I suspect i don't have problem with this.

As I have read from other generator manuals, such as stamford, the minimum insulation resistance should be at least 1M. Do you agree that my exciter stator and rotor has to be rewinded? By the way this generator is at least 25 years already (Caterpillar)

Any comments and suggestion is very much appreciated. Thanks.

 

[waross]

Is the generator working or has it failed in service? What size is this set?

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[edison123]

Post the nameplate details of the generator.

Muthu

http://www.edison.co.in