Armature for latching a circuit breaker trip unit

摘要

A latching system for a circuit breaker is arranged to actuate a trip unit and interrupt circuit current upon occurrence of a short circuit or an overcurrent condition. The latching system employs an armature having a recess formed therein and a cradle having a cradle tip arranged to releasably engage the recess. A thermal magnetic trip unit is depicted within the circuit breaker for the purposes of detecting overcurrent conditions through the electric path. During current transport through the circuit breaker, the current is thermally sensed by means of the bimetal and magnetically sensed by means of the magnet. The armature rotates against the return bias of a compression spring to release the cradle tip from the recess and allow counterclockwise rotation of the contact arm. The rotation of the contact arm causes the separation of the movable and fixed contacts under the urgence of a mechanism spring.