Forum: Reliability & Maintainability Questions and Answers
Topic: Reliability & Maintainability Questions and AnswersTopic Posted by: Reliability & Maintainability Forum (firstname.lastname@example.org )
Organization: System Reliability Center
Date Posted: Mon Aug 31 12:47:36 US/Eastern 1998
Original Message:Posted by:Lawrence Lacuesta (Lawrence.Lacuesta@tas.alcatel.ca )
Date posted: Tue Apr 3 17:00:43 US/Eastern 2001
Subject: Relay Failures
hi! The failed relay is solder-mount on a standard 3U PCB, pluggable, ground mobile environment, operating at least 150,000 cycles/year, current rating is 10% of rated load at 1A (lamp). Relay is rated 100,000 cycles @ rated load. Failure Analysis result: The relay contact shorted to the coils was caused by broken moving contact spring. The normally closed contacts remain open when the voltage was removed from the coils (de-energized) was caused by damage/fractured of the over-travel spring and broken weld joint of the armature hinge pivot, which prevented the armature from assuming the drop out position. Per manufacturer, the weakest point on the relay is the spring that is sitting directly on top of the contact pins inside the relay enclosure. Is the above result caused by shock and vibration and not over cycling? Thanks in advance!