acceptance criteria for syncronous machine slip ring scratches 1

[electricpete]

We have a syncronous machine. Manufacturer requires < 10 mils runout on slip rings.

Does anyone know what level of scratches on slip rings (caused by work near slip rings) is acceptable?

Would 10 mil deep scratch be acceptable? Any thoughts or references?

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[electricpete]

btw, I use the term mil to mean 0.001 inches.

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[DougMSOE]

The slip rings should have a mirror finish to them. One single groove should not be a problem.
However, what does concern me is the run-out.
10 mils better be for a low RPM motor (below 600 RPM)

 

[electricpete]

This is a 600 RPM 5MW generator.

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[jbartos]

Suggestion: It may be relative. The remedy will be left at the owner discretion. Certainly, a cost of downtime may be a big factor.