Historical data on motor insulation dissipation factor

[Younsi]

Hi everyone,
I am looking for information and references on the possible correlation between motor life/reliability and Capacitance and Disspation Factor values. I am an EE and know about the meaning of C and DF but have never seen decent data showing clearly the value of this test (IEEE28) over time. Can anyone provide me help on this ? The question is about motors but relates to hydro and turbo generators as well.
With my best regards
Karim

 

[electricpete]

EPRI has done some studies where they artificially aged insulation and subjected it to various tests during aging process and tried to answer the type of question you're asking. One of the reports is TR 100185. There are a few other report numbers I can dig up if you want, but it won't do you any good unless your company is an EPRI member.

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[Younsi]

Electricpete
Many thanks for your help. I happened to have joined Ontario Hydro when that TR 100185 report was being finalized. Great work and very informative data. They tested 4 or 5 motors under different conditions and looked at various test methods and how they correlated.
I wish I could access the other reports you mentioned but my company is not a member of EPRI.
The best for me would be of coure to have an example of maintenance data over the life of a motor that ended up failing in service !
Best regards
Karim