Motor insulation testing - Polarization Index and loss-tangent testing 1

[Anok]

Could anyone explain the difference between Polarization Index and loss-tangent testing.

Since, both testings are checking the insulation of windings. Any pros and cons?

Thanks.

 

[7anoter4]

Hi Anok
For Polarization Index see:

http://www.alltestpro.com/documents/AreviewofpolarizationindexandIEEEstandard43-2000_000.pdf

for other see

http://findarticles.com/p/articles/mi_qa3726/is_200508/ai_n14879852

May be useful.
regards

 

[electricpete]

polariation testing uses much more commonly available equipment (megger type tester). It is the same as insulation resistance test, except you apply voltage for 10 minutes and take ratio 10minute/1 minute resistances.

tan delta or power factor uses more expensive equipment. Operation of the equipment can be a little more complex.

For motors, typically it would not be an either/or. You are always going to do IR / PI . If you want extra analysis / assurance, you also do a tan delta.

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[7anoter4]

Thank you, electricpete.It is very interesting, indeed.