ELECTROMAGNETIC SWITCH INCORPORATING CONTACT DISPLACEMENT LIMITING MEMBERS FOR PREVENTING UNRELIABLE OPERATION CAUSED BY WEAR OF SWITCH CONTACTS

摘要

In an electromagnetic switch, current flow through a coil causes a plunger to be axially displaced by magnetic attraction, against a restoring force of a return spring, thereby axially displacing a movable contact against fixed contacts and so enabling current flow via the contacts. One or more contact displacement limiting members are disposed on the opposite side of the fixed contacts from the movable contact, for limiting the extent to which the movable contact can be axially displaced when the fixed contacts have become worn by repetitive switching operations. A condition in which the movable contact cannot be restored to a “contacts open” position is thereby prevented.