Westinghouse Electric Corporation

Eaton Corporation

Richard P Sabol

Robert Tracy Elms

John Joseph Shea

Robert J Clarey

Ronald A Cheski

William E Beatty, Jr

Louis Paich

Kenneth W Sanner

A GFCI/AFCI circuit breaker includes a housing, separable contacts, and an operating mechanism for opening and closing the separable contacts. A first trip mechanism includes a GFCI/AFCI trip circuit having a resistor. The resistor is energized in response to a trip condition. The first trip mechanism cooperates with the operating mechanism to trip open the separable contacts in response to the trip condition. The resistor has a body which burns open in response to a failure of the separable contacts to trip open. A second trip mechanism engages the body of the resistor and cooperates with the operating mechanism to trip open the separable contacts in response to the body of the resistor burning open.

Circuit interrupter employing a mechanism to open a power circuit in response to a resistor body burning open

A multiwire branch circuit including two line conductors and a grounded, common neutral conductor is protected by a two pole circuit breaker connected to independently interrupt overcurrent conditions in the two ungrounded line conductors. Three separate protection circuits provide arc fault protection for each of the ungrounded line conductors and ground fault protection for all three conductors. The arc fault detectors use the bimetal of the thermal-magnetic trip device for the associated line conductor for current detection, and therefore, are individually referenced to the associated line voltage. Hence, the outputs of the arc fault detectors are electrically isolated from each other and from the output of the ground fault detector, but operate a common trip circuit to simultaneously open both poles of the two pole circuit breaker. The arc fault detectors have separate isolated power supplies. The ground fault detector is powered by a supply which is energized if either of the ungrounded line conductors is energized.

Apparatus for detecting arcing faults and ground faults in multiwire

A circuit breaker has a magnetic trip assembly which can be adjusted to trip the breaker for low level overcurrents in the range of five to ten times rated current. The magnet trip includes for each pole of the breaker a helical torsion spring having one torsion arm which biases an armature against an adjusting bar to form a gap between the armature and a stationary magnetic structure in which magnetic flux strong enough to attract the armature and trip the breaker is induced by overcurrent. A second torsion arm of the spring has a first portion which bears against and slides along a pivot member carried by the adjusting bar to adjust the bias force applied to the armature by a given amount per unit travel of the adjusting bar over a low trip current portion of the range of travel of the adjusting bar. A second terminal portion of the second torsion arm of the spring extending at an angle from the first portion engages and slides along the pivot member on the adjusting bar to provide a greater change of bias force per unit travel of the adjusting bar at the higher trip current settings. Movement of the adjusting bar adjusts the spring bias for all poles of a multiphase circuit breaker simultaneously. The gaps between the armatures and the fixed magnetic structures of all the poles can also be adjusted by camming surfaces on the adjusting bar.

Circuit breaker with adjustable low magnetic trip

A circuit breaker is disclosed having a movable magnetic core provided in the magnetic trip assembly thereof adapted to lower the current levels at which the magnetic trip mechanism will operate. The magnetic trip assembly also includes a pivotally connected armature, a current carrying conductor, a fixed magnetic yoke and a latchable operating mechanism. A primary air gap exists between the armature and the fixed yoke. The movable core is designed to move into an extended position which reduces the primary air gap which in turn increases magnetic flux coupling which allows the magnetic force required for the armature to pivotally rotate to unlatch the operating mechanism and thereby trip the circuit breaker to be generated at a lower current level. This reduction in current is the desired effect of the new design.

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Munhall, PA, United States of America

Richard P Sabol