Relay Armature Rebound Analysis

In numerous types of mechanisms it is desirable to arrest the motion of a member at a particular point and to maintain it in this position. One of the simplest means of accomplishing this is to allow the moving member to impinge on a fixed member (stop) and to provide forces to tension it against this stop. Because the member to be arrested possesses kinetic energy and because the stop cannot generally absorb all of this energy, the moving member will rebound from the stop. The rebound motion generally deteriorates the performance of the mechanism and should be minimized. Investigation of this phenomenon has been stimulated by the armature rebound problem in relay operation, where rebound from the front stop* tends to reclose contacts and must therefore be compensated for by additional (waste) travel, resulting in deleterious effects on speed and * Among relay designers the f r o n t stop has been generally referred to as " b a c k s t o p " . In this paper t h e terms f r o n t s t o p and heel s t o p h a v e been used t h r o u g h out for easier identification. 172