Westinghouse Electric Corporation

Eaton Corporation

Stephen A Mrenna

Kurt A Grunert

Glenn R Thomas

Alfred E Maier

Michael Jerome Whipple

Edward Ethber Lias

Michael Joseph Erb

James P Ellsworth

Kathryn M Palmer

Melvin A Carrodus

Charles E Haugh

John Joseph Shea

James Gerard Maloney

John A Wafer

Richard Paul Malingowski

Craig Joseph Puhalla

Henry Anthony Wehrli, Iii

Walter V Bratkowski

Jere L McKee

Kevin Anthony Simms

Jeffrey A Miller

Keith Edward Thomas

Robert J Tedesco

Raymond W MacKenzie

William Kingston Hanna

Lawrence M Hapeman

Zelko J Kruzic

Vijay K Garg

Jonathan Weiss

Joseph R Manuel, Iii

Richard W Weaver

David M Wood

Daniel Edward Schiller

Gale C Vosler

Michael J Erb

The high transient current sustained by arcing during opening of the main contacts of a miniature circuit breaker is commutated out of the bimetal by deflection of the bimetal in response to the overcurrent to close secondary contacts on the free end of the bimetal and on a low resistance by-pass conductor shunting the bimetal. The by-pass conductor can be extended toward the movable contact arm carrying the movable main contact to commutate some of the overcurrent into the by-pass conductor earlier in the opening sequence to reduce the energy input to the bimetal and reduce the force closing the secondary contacts.

Circuit breaker with bypass conductor commutating current out of the bimetal during short circuit interruption and method of commutating current out of bimetal

A bypass conductor is provided for use in a miniature type circuit breaker. In one embodiment, the bypass conductor can include an elongated flat strap positioned in a circuit breaker housing. A first end of the bypass conductor is positioned to be adjacent to a contact arm in an open circuit position of the circuit breaker to receive current flow, especially high transient current flow. A second end of the bypass conductor is electrically coupled and/or mechanically connected to a load terminal of the circuit breaker to provide a path for current between the first and second ends. In this manner, the bypass conductor provides an alternate path for electrical current through the circuit breaker. The bi-metallic components and other sensitive elements within the circuit breaker can therefore resist the loss of useful life and other adverse operational effects caused by a high transient current event.

Circuit breaker with bypass for redirecting high transient current and associated method

A current-limiting device includes a current-limiting material, such as a molded thermoset material, and first and second electrodes structured for carrying current through the current-limiting material. The first electrode electrically engages a first portion of the current-limiting material, and the second electrode electrically engages a second portion of the current-limiting material. A mechanism provides a non-uniform pressure distribution between one or both of the first and second electrodes and the current-limiting material.

Current-limiting device employing a non-uniform pressure distribution between one or more electrodes and a current-limiting material

A circuit interrupter including a housing, separable main contacts disposed in the housing, and an operating mechanism disposed in the housing and interconnected with the contacts. A trip mechanism is disposed in the housing and has an automatic trip assembly that selectively generates a tripping operation to cause the operating mechanism to open the contacts upon a predetermined current threshold. The automatic trip assembly includes a magnetic yoke, an armature, and an electrical terminal. The magnetic yoke has pivot supports on which are positioned pivot arms of a head portion of the armature. A clamp member applies a clamping force to the head portion of the armature in a direction to normally rotationally displace a bottom portion of the armature away from the yoke and the terminal.

Circuit interrupter with a magnetically-induced automatic trip assembly implementing a spring clamp

A circuit interrupter including an operating mechanism and separable main contacts interconnected with load and line terminals has an interface region between the top and bottom portions of the completed housing thereof, which may be of reduced cross section relative to the remainder of the side walls of the circuit interrupter for being moved or pushed outwardly under the pressure of expanding gas during a circuit interruption operation. To more easily clear or separate abutment surfaces by near lateral movement thereof to provide a small opening for pressurized gas to escape the elasticity of the side wall is utilized for this purpose. Provided that the elasticity limit is not exceeded, the wall will return to its original position sealing the internal portions of the circuit interrupter from the exterior once the gas pressure has dropped below a predetermined level.

Molded case circuit breaker with pressure release mechanism

A circuit breaker system with a shunt trip device is taught in which the shunt trip device occupies a miniature circuit breaker case and utilizes features of the miniature circuit breaker case except that it is provided with a coil and two-piece armature which initiates the shunt tripping operation when properly energized to thus open the separable main contacts of side-by-side mounted circuit breakers having the same intermediate axial member. A back plate is provided for the two-piece joined armature member in the central region of the toroid, solenoid or coil to assist the snug fit of the two-piece core within the central opening of the bobbin of the solenoid and to provide a low reluctance bypass for the magnetic flux crossing the gap formed by the end abutments of the two-pieces of the magnetic core.

Miniature circuit breaker with shunt trip device

A circuit breaker has a shock absorber to prevent nuisance tripping which results from shock generated during ON to OFF operation of the circuit breaker. The shock is primarily caused by a snap action which occurs within the operating mechanism of the circuit breaker when the handle is moved from the ON to OFF position. The snap action results from the circuit breaker employing, as part of the operating mechanism, a toggle mechanism within an over center tension spring as a means for imparting motion in the operating mechanism. By strategically positioning the shock absorber for engagement with the operating mechanism when the circuit breaker is in the OFF position, the shock may be effectively absorbed thereby preventing the undesirable nuisance tripping.

Shock absorber for circuit breaker

A support plate for a circuit breaker has a longitudinal slot centrally located in the support plate, a free end with a tab for affixing an elongated bimetal of a trip assembly, a longitudinal edge opposite to the free end and terminating in proximity to a latch ledge of a cradle of an operating mechanism, opposed lobes each having a transverse edge, and an opening in each of the transverse edges. The support plate extends partially along a planar wall of a base of a housing for the circuit breaker. Molded pins in the base of the housing of the circuit breaker enter the openings in the transverse edges of the support plate for securing the support plate to the base. These molded pins extend outwardly to space the support plate away from the cradle of the operating mechanism. Bent over tabs are provided in one of the lobes for abutting a cover of the circuit breaker to maintain the fixed position of the support plate in the housing base.

Support plate for a circuit breaker

In a circuit breaker having a thermal-magnetic trip, the voltage across the bimetal is used to sense load currents. This voltage signal representative of current through the bimetal can be used as an input to an arcing fault detector. The signal is converted to a bandwidth limited di/dt signal. If the magnitude of the di/dt signal exceeds a threshold indicative of the onset of an arc a predetermined number of times within a given interval, the circuit breaker is tripped. The voltage across the bimetal can also be used in other devices requiring a measure of load current such as, for example, a meter or an overcurrent alarm.

Circuit breaker using bimetal of thermal-magnetic trip to sense current

A case for a circuit breaker provides a base and a cover, both having an inner surface ribbing system and an inner surface coring system. The ribbing systems form an inner cavity retaining a circuit breaker mechanism and an outer aperture area for receiving a handle for manual operation of the mechanism. The handle is supported in the arcuate areas of the coring systems near the aperture area. A barrier member is located adjacent to the arcuate area in the base, and a barrier member is located adjacent to the arcuate area in the cover. When the base and the cover are assembled the two barrier members are spaced away from the handle and overlap the handle in the arcuate areas to separate the outer aperture area containing the handle from the inner cavity containing the circuit breaker mechanism and still allow the handle to extend freely down into the inner cavity for its connection to and operation of the circuit breaker mechanism. The width or thickness of the barrier member in the base is about 0.125 inches and that in the cover is about 0.156 inches.

Handle barrier in a molded case for a miniature circuit breaker

A molded case for a miniature circuit breaker provides a base and a cover whose outer mating peripheral walls, which form and enclose a cavity for housing a circuit breaker mechanism, have approximately equal widths, except for the projected handle area. In this handle area, the width of the peripheral wall of the base is increased and contains an aperture for receiving the handle, and the width of the peripheral wall of the cover is decreased to receive the increased aperture area of the base. This arrangement provides for full handle support in the base for ease of assembly; high ribbing for maximum strength for short circuits; and a minimum overall thickness of about 0.500 inches.

Molded case for a miniature circuit breaker

A bolt-on, duplex circuit breaker having an external, integrally formed key member designed with a truncated pyramidal shape. The pyramidal shape is used to discourage tampering aimed at its removal. A panelboard into which bolt-on, duplex circuit breakers are mounted having mounting rails onto which the circuit breakers are disposed. The mounting rails have cooperating, key member accepting notches that act in conjunction with the key member integrally formed upon the circuit breaker for limiting the number of bolt-on, duplex circuit breakers that are insertable within the panelboard.

Bolt-on, duplex circuit breaker rejection assembly

A multipole circuit breaker, for example, a three pole circuit breaker, can detect a condition when less than all of the phases are open circuited to trip the circuit breaker. This reduces the tripping time and hence risk of damage to the electrical load. The circuit breaker includes a thermal trip unit and a phase sensitivity assembly that is interlocked with the bimetals included with the thermal unit. The phase sensitivity assembly includes one or more levers, responsive to the deflection of a bimetal corresponding to the open circuited phase resulting from cooling action of a bimetal relative to the other bimetals. The relative displacement of the cooling bimetal is used to either trip or reduce the tripping time of the circuit breaker.

Phase sensitivity

A mounting tab plate for a panelboard has been designed, so that two such plates can be used in pairs on each pole for gang-mounting of multipole circuit breakers, the plates being fixed on the panelboard on opposite sides by a screw after insertion of the tab in a corresponding groove of the housing of the circuit breaker.

Panelboard circuit breaker mounting assembly

A circuit breaker with a thermal trip has a calibration opening in the electrically insulating housing through which a tool may be inserted and rotated to distort a support plate on which a bimetal is mounted to calibrate the thermal trip after the circuit breaker has been fully assembled and enclosed within the insulating housing. A tamper indicating seal in the form of a destructible film secured over the calibration opening by an adhesive having an adhesive strength exceeding the tensile strength of the destructible film provides a visual indication of any subsequent attempts to tamper with the calibration setting.

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Brighton Township, Beaver County, PA, United States of America

Stephen A Mrenna