Abstract: An operating mechanism assembly used within molded case circuit breakers employing electronic trip units interconnects the operating mechanism with the circuit breaker movable contact arms by means of a slotted-cam arrangement. The slotted-cam optimizes the manual closing of the movable contact arms by controllably over-centering the circuit breaker operating mechanism springs.

Abstract: A molded case circuit breaker of the type using electrodynamic repulsion to separate the circuit breaker contacts under intense overcurrent conditions also includes an arc chute arrangement for cooling and quenching the arc that occurs during such contact separation. A plastic cover insert added to the interior of the circuit breaker cover multi-functionally retains the arc chute within the circuit breaker case while providing clearance for the circuit breaker operating handle shutter. A resilient pad on the top surface of the cover insert receives the circuit breaker operating handle skirt upon contact separation and dampens the energy imparted to the operating handle and to the circuit breaker cover.

Abstract: A positive trip indication spring is used with circuit breakers that provide colored trip indication through a visual access opening in the circuit breaker cover to ensure that the trip indicia on the circuit breaker operating handle align with the visual access opening upon the occurrence of a trip condition. The trip indication spring cooperates with the powerful circuit breaker operating mechanism springs to provide additional bias to the circuit breaker operating handle to move the operating handle to its fully "TRIPPED" position.