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Forum: Reliability & Maintainability Questions and Answers

Topic: Reliability & Maintainability Questions and Answers

Topic Posted by: Reliability & Maintainability Forum ( )
Organization: System Reliability Center
Date Posted: Mon Aug 31 12:47:36 US/Eastern 1998

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Original Message:

Posted by: J Turnbull ( )
Date posted: Thu Mar 14 10:53:39 US/Eastern 2002
Subject: Electric Permanent Magnet Motor
Does anyone have any experience with reliability predictions for Permanent Magnet Electric Motors? I am looking for an Overall target for the motor Reliability/failure rate.


Subject: Permanent Magnet Electric Motor
Reply Posted by: B.W.Dudley ( )
Organization: RAC
Date Posted: Thu Mar 14 15:29:07 US/Eastern 2002
As a target failure rate, the composite value in the RAC NPRD-95 for Induction Electric Motors could be used as a beginning. This rate,14.41 failures per million hours, is based on units operating in ground fixed conditions. As I have suggested in a previous forum response, you should perform a detailed mechanical reliability analysis to truly estimate the reliability. Of course, the best information is always actual test or operating information which is difficult to obtain.


Subject: Re
Reply Posted by: J Turnbull
Date Posted: Fri Mar 15 5:46:13 US/Eastern 2002
I have already broken the EM into its component parts and calculated its reliability. It will be used on wing and therefore has to have certain targets that it can meet. My target at the moment is 150,000 Op Hours MTBF. I feel that this is too high (a/c service life is 138,000 flight hours). I am trying to get an idea of what is an achievable target. Any ideas where I might get this info?

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