CIRCUIT BREAKER CONTACT ARM WITH VARIABLE FORCE PIVOT

摘要

The invention relates to a circuit breaker having a movable contact arm pivotally mounted on a contact arm carrier and adapted to be electrodynamically blown open upon the occurrence of a high-level overcurrent. …The contact arm (23) has associated therewith a contact pressure spring (61) having a force arm (67) which acts upon a tail portion of the contact arm to normally hold the latter in a position constraining it to move as one with the contact arm carrier (43), and to provide contact pressure when the contacts (17, 19) are closed. As the contact arm is blown open, the force arm (67) of the spring slides toward and at least to the contact arm pivot (25), whereby the contact-pressure providing spring force on the contact arm is reduced essentially to zero.