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: Shanta
Date posted: Tue May 20 9:54:10 US/Eastern 2003
Subject: Resistor RACRates Model - PRISM
Message:
This question is in reference to the Resistor RACRates Model in PRISM software. It requires a combination of thermal stress (in the form of calculated element temperature) and rated power parameters. Depending on the Element Temperature Calculation option chosen, the user is required to enter different pieces of data. If you select Option 5, you need to enter delta-temperature stress, rated power dissipation and actual power dissipation. What is delta temperature stress (Delta-T)? How is it different from the other 4 options which use ambient temperature, temperature rise, ThetaJC (or ThetaJA)*P?

Reply:

Subject: Resistor RACRates Model - PRISM
Reply Posted by: David Dylis (ddylis@alionscience.com )
Organization: Reliability Analysis Center (RAC)
Date Posted: Tue May 20 10:23:36 US/Eastern 2003
Message:
Thank you for your inquiry regarding the RAC PRISM prediction methodology.

Delta-T is equivalent to the temperature difference between the resistor element and the resistor ambient temperature. It is similar to other calculation options which use ambient temperature, temperature rise, ThetaJA*P except that the temperature difference is input by the user and not calculated by PRISM.

If you have any additional questions, feel free to contact me.

For more information on PRISM go to the RAC PRISM Web Site (http://rac.alionscience.com/prism).