Patent ID: 6054912
Filing Date: 2000-04-25
Classification: H01H

Abstract:
A trip device of a circuit breaker having an operating mechanism for closing and opening switching contacts, and a trip latch working said operating mechanism when released to open said switching contacts, said trip device comprising a stationary core and a movable core which is attracted to said stationary core when current flowing through a circuit exceeds a predetermined threshold to release said trip latch, and said trip device further comprising:an operating member having engagement means for engagement with said movable core and moving via said engagement means when said movable core is attracted;stopper means for interrupting movement of said operating member while said movable core is attracted so as to prevent release of said trip latch;an operating spring charged with force when said movable core is attracted and discharging the force when said movable core returns so as to move said operating member by the discharged force; anda returning spring biasing said operating member which is moved when said operating spring discharges the force in a direction toward its original position, whereinsaid operating spring discharges the force when the current flowing through said circuit decreases and said operating member with its movement interrupted by said stopper means by the discharged force moves to a position which does not allow said movable core attracted again when said current again exceeds said threshold to engage with said engagement means.