RF Testing 1

[aprilee]

I'm not very familiar with RF testing and it's benefits. Does anybody know how often it should be done? How important is it in identifying motor failures before they occur? Any information on the subject is highly appreciated. Thanks!

 

[aolalde]

For motor predictive maintenance tests see thread237-10535
Could you explain the meanning of "RF testing"?

 

[electricpete]

http://www.national-electric-coil.com/Library/ArticlesPubs/WHM-PD-ACGens.pdf

See page 5

One method, EMI (electromagneticinterference), is a very useful tool in determining generator condition, even when there is serious external “noise.” Instead of PD couplers, data is collected with the in-service installation of a split core radio frequency current probe.

Jim Timperly of AEP published several papers on this although I don't think any are free:

http://www.google.com/search?q=timperley+EMI+diagnostics&hl=en&start=0&sa=N

It is not a very common technique

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[electricpete]

Also when a medium voltage motor is disassembled in the shop, you can use a TVA probe to search for defects in the slot. I guess that might also be called RF testing, but I suspect you are more likely referring to the "EMI diagnostic" technique discussed in the linked above.... it is performed with the motor running (TVA probe requires motor disassembled). And of course several versions of partial discharge testing... but that is universally called partial discharge. On the other hand "EMI Diagnostics" is such a poorly named technique (it's not interfering with other systmes) that many people call it RF testing instead.

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[aprilee]

Thanks guys. Our company uses RF (Radio Frequency) testing as opposed to EMI testing. RF testing - Records signatures at each frequency band in a standard testing format. Results are compared to previous readings to determine if degradation has occurred. From the responces I got, it doesn't seem like this test is pretty common.