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: Richard Smith
Date posted: Tue Mar 18 10:22:38 US/Eastern 2003
Subject: CHR Capacitor Shelf Life/Aging
Message:
Can anybody please refer me to a source of information on Capacitor Aging and Shelf Life (aging mechanisms and reliability of older components). I am particularly interested in CHR capacitors (fixed, metallized, plastic film dielectric). Thanks in advance.

Previous reply

Reply:

Subject: Capacitor Non-op Degradation
Reply Posted by: BWD (bdudley@rac.alionscience.com )
Organization: RAC
Date Posted: Wed Mar 19 10:44:44 US/Eastern 2003
Message:
All components have degradation due to corrosion over time when in an uncontrolled non-op condition. Inaddition, electrolytic capacitors have a degradation mechanism due to loss of electrolyte by means of vapor transmission through the end seal. The rate of loss is a function of the storage temperature. Film capacitors do not have this degradation problem, so all you need to be concerned with is the corrosion. Sealing the parts or units in a bag that is back filled with dry nitrogen is one way of controlling the environment. By the way, electrolytic capacitors can be re-aged every two or three years by slowly applying voltage with a resistor in series.