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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: Clay Davis
Date posted: Fri Feb 11 19:08:45 US/Eastern 2000
Subject: Reliability of Fans
Does anyone know where I can find reliability data for DC Fan Motors. The fan is used inside a computer and its a 40x40x28mm with ball-bearing construction. I referenced the NPRD data for a Fan, Axial, Tube but the failure rate for 46.8 to 1123.4 for ground benigh. I am esp interested in MTBF vs Temp and Fan Speed. Also, what are the failure modes (lock-up, electrical stress, etc) and % of occurence would be great. Thank you.


Subject: Fan Reliability
Reply Posted by: Bruce Dudley ( )
Organization: Reliability Analysis Center
Date Posted: Thu Feb 17 16:03:06 US/Eastern 2000
I looked in the NPRD-95 handbook (page 2-910)and found failure rates for Fan, Axial, Tube to be far less than the rates that you have indicated. Commercial products show failure rates of 1.123 x 10^6 hours for ground benign and 2.111 failure per 10^6 hours for ground fixed conditions. On the next page (2-92), I found a failure rate for a Fan, Cmputer Peripheral to be 1.9 failures per 10^6 hours. The primary failure problems are open windings and sized bearings. Both of these failure conditions are related to speed, load and temperature.

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