SRC Forum - Message Replies

Forum: Reliability & Maintainability Questions and Answers

Topic: Reliability & Maintainability Questions and Answers

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

Original Message:

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

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Reply:

Subject: Negative temperature
Reply Posted by: Jean-Marie Cloarec (jean-marie.cloarec@ligeron.com )LIGERON S.A.
Date Posted: Wed Oct 30 12:02:30 US/Eastern 2002
Message:
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 à -50°C than at +50°C !!! 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 = -273°C, I have a infinite failure rate.