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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: Jean-Marie CLOAREC ( )
Organization:LIGERON S.A.
Date posted: Fri Oct 25 10:11:26 US/Eastern 2002
Subject: Negative temperature
How calculate failure rate when ambiant temperature is negative. MIL HDBK 217 + RDF + ... are based on temperature from 0C to ... but when temperature is for example -25C ?

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Subject: Negative temperature
Reply Posted by: Jean-Marie Cloarec ( )LIGERON S.A.
Date Posted: Wed Oct 30 12:02:30 US/Eastern 2002
I agree it's possible to use negative tempeprature in Pi-T formula, but in this case, the Pi-T decrease and the failure rate increase. This mean that an electric component will be more reliable -50C than at +50C !!! If I use absolute temperature, this problem is corrected. But I'm not sure that models were elaborate for both temperature : positive and negative ? In the worst case, is temperature = -273C, I have a infinite failure rate.

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