Apparatus for monitoring the wear upon carbon brushes in electrical machines

摘要

The wear upon at least one of several carbon brushes in a brush holder is monitored by a lever one arm of which is biased against the rear end face of a selected brush by a spring and another arm of which actuates a microswitch in response to a predetermined amount of wear upon the brush as a result of engagement with a commutator or a slip ring, namely in response to a predetermined angular displacement of the lever from a starting position which is assumed by the lever when its first arm engages a freshly inserted brush.