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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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Posted by: Kang Zhang
Date posted: Wed Aug 16 17:01:48 US/Eastern 2000
Subject: Mechanical Relay; failure mode percentages for Mechanical portions
Does someone know the percentage of breakdowns for mechnical failures of relays. i.e. something beyond just open and short? Specifically how often the contacts and reed would fail versus how often the coil itself would fail. Thanks in advance! Kang


Subject: Relay Failure Modes
Reply Posted by: Bruce Dudley ( )
Organization: Reliability Analysis Center
Date Posted: Tue Aug 22 14:32:25 US/Eastern 2000
From the RAC report FMD-97 "Failure Mode/Mechanism Distribution", I found information on contact and coil failure modes. The percentages for each looks like 33% for contacts and 7% for coils. This was an interpretation of the data presented and was developed as follows: Contact Failures - High Resistance - 12% Drift Resistance - 3% Degradation Resistance - 3% Intermittent Contact - 6% Open Condition - 6% Shorted Condition - 3% Total----33% Coil Failures - Open condition - 2% Shorted Condition - 1% Wire Damage - 4% Total-----7%

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