General Electric Company

Erich J Pannenborg

Joseph M Palmieri

Raymond K Seymour

Andre J M'Sadoques

Robert Casagrande

Gary Paul Michaelis

Roger N Castonguay

Javier I Larranaga

Joseph Criniti

Richard E Bernier

Michael C Von Kannewurff

Gerardo Rosario

Franklin P Palaia

A contact arm assembly is provided having an electrical contact for making and breaking an electrical current, a contact arm for supporting the electrical contact, and a bond surface on the contact arm that is conditioned for improving the bond between the electrical contact and contact arm. Also provided is an electrical circuit breaker that utilizes the improved contact arm assembly. The bond surface of the contact arm is provided with pyramid-shaped serrations that serve to more uniformly distribute the electrical current during brazing, provide multiple areas of localized current constriction during brazing, and provide collector pockets for accumulating the molten braze alloy during brazing. The uniform distribution of electrical current during brazing serves to generate a uniform temperature gradient across the braze area for uniform melting of braze alloy. The multiple areas of localized current constriction during brazing serves to temporarily elevate the temperature of the braze joint during brazing by localizing the heat generation proximate the braze alloy, thereby effectively reducing annealing of the contact arm. The collector pockets for accumulating the molten braze alloy during brazing effectively eliminates the overflow of braze alloy onto the edges of the contact and contact arm. A contact arm assembly having uniform melting of braze alloy, reduced annealing of the contact arm, and reduced overflow of braze alloy onto the edges of the contact and contact arm results in an improved bond of contact to contact arm.

Electrical contact arm assembly for a circuit breaker

Multi-pole circuit breakers are joined together to form a common assembly. The individual poles are in the form of compact circuit breakers having a pair of separable contacts controlled by a single externally-accessible operating handle. The individual circuit breakers are riveted together and are keyed such that the contacts open and close in unison. The individual handles are interlocked together by means of a unitary plastic handle tie.

Circuit breaker handle interlock

A residential circuit breaker electromagnetic trip unit facilitates the assembly of the trip unit components by use of a pair of braid connectors for connection between the trip unit magnet and the circuit breaker contact arm. The trip unit bimetal is directly welded to the trip unit magnet and the braid connectors for reduction in material and labor costs. The contact arm and the magnet are shaped to present a parallel path connection between the contact arm and the magnet for close fit tolerance. The front surface of the magnet is configured to prevent magnetic adhesion between the magnet and the trip unit armature under intense short circuit overcurrent conditions.

Residential circuit breaker having an enhanced thermal-magnetic trip unit

A modular plastic trip bar assembly joins separate single pole molded case circuit breakers into a single multipole circuit breaker. The addition of the trip cam to the trip bar assembly allows four and five pole combinations to operate in unison.

Modular trip bar assembly for multipole circuit breaker

A molded case circuit breaker for residential use employs an additional safety feature to ensure a fail-safe condition in the event that the circuit breaker is installed within a circuit that may be subjected to an excessive over-current fault that disables the circuit breaker trip unit. The integral bimetal-fuse within the circuit breaker trip unit responds to interrupt circuit current before any damage can occur to the associated electrical wiring system.

Fail-safe residential circuit breaker

A molded case thermal-magnetic circuit breaker having improved low current magnetic trip response pivotally arranges the magnet within the circuit breaker thermal-magnetic trip system for controllably moving toward the latching armature assembly. The movement of the magnet decreases the magnetic separation distance between the magnet and the latching armature to optimize the magnetic trip forces and thereby enhance low current magnetic trip response.

Thermal-magnetic trip unit with low current response

A circuit breaker latch assembly eliminates the need for polishing the opposing latch surfaces to reduce static surface friction and lower the latching force. The end of the circuit breaker cradle operator is offset relative to the restraining surface of the armature-latch to reduce the static friction that must be overcome to move the armature-latch away from the cradle operator. Subsequent release of the cradle operator then allows the circuit breaker operating mechanism to separate the circuit breaker contacts upon the occurrence of predetermined overload current conditions.

Molded case circuit breaker low friction latch assembly

A molded case circuit interrupter of the type employing a thermal-magnetic trip unit to interrupt circuit current utilizes a flexible electrical braid conductor to connect between the thermal-magnetic trip unit and the movable contact arm. A helical spring arranged around the braid conductor at the welded connection with the movable contact arm provides long-term strain relief. A metal phosphate coating on the surface of the circuit breaker operating cradle and latch assembly eliminates polishing while insuring release of the cradle from the cradle-latch interface surfaces.

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Southington, CT, United States of America

Erich J Pannenborg