Abstract: A circuit breaker having a trip actuator which mechanically trips the breaker in response to an electrical trip pulse. The trip actuator includes first and second parallel magnetic circuits, with the first circuit having a lower reluctance than the second circuit. A magnet provides magnetic flux for both circuits. A pivotally mounted clapper has a first position in which it is releasably held in the first circuit by a magnetic force, and a second position. Bias springs urge the clapper towards the second position, with the bias springs providing a biasing force which is less than the magnetic force holding the clapper. The electrical trip pulse creates a magnetic flux which opposes the magnetic flux in the first circuit, switching the magnetic flux to the second circuit. The clapper member pivots to the second position, and a trip link associated with the clapper actuates a trip mechanism.

Abstract: An alarm assembly for use with a circuit breaker is provided. The assembly is used with the flux shunt trip device of the circuit breaker. The flux shunt trip device has a plunger which moves from a retracted position to an extended position to interrupt current through the circuit breaker upon a predetermined condition. The assembly includes an actuating member mounted in engageable relationship with the plunger so that when the plunger moves to its extended position, the actuating member moves to an actuated position. In the actuated position, the actuating member contacts a switch mechanism to actuate a switch which may be connected to an alarm or light indicator to identify that the circuit breaker has tripped. The actuating member remains in its actuated position until it is manually reset. A mechanism is provided for reset of the device.

Abstract: A circuit breaker having a chassis, an electrical contact structure, and a shock absorber mechanism. The contact structure includes a movable first electrical contact and a second electrical contact. The first contact has a first movement range. The shock absorbing mechanism, which absorbs energy from the movement of the first contact, includes a metallic bar pivotally mounted on the chassis, and first and second limit members fixed to the chassis. The first and second limit members define a second movement range which overlaps the first movement range. A spring weakly biases the metallic bar towards the second limit member. The first contact, during movement thereof to an open position, strikes the metallic bar. Kinetic energy is removed from the first electrical contact by the metallic bar without bounce of the electrical contact, and the metallic bar pivots against the first limit member, transferring the shock of stopping the first contact to the chassis.

Abstract: 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.

Abstract: In an electrical transition a nonconductive base has at least one side rail and at least one interior rail spaced apart from a side rail and a wire connector fitted therebetween. The side rail and interior rail prevent the connector from moving across the base. A bus bar is placed on the base and has a tab extending into the opening of the connector.

Abstract: A power circuit breaker having movable and relatively stationary contact assemblies operable between open and closed positions. The contact assemblies respectively include pivotally mounted first and second conductive members. The first and second conductive members are disposed in spaced relation in the closed position of the circuit breaker, to provide a first current loop having first and second legs defined by said first and second conductive members. A pivotable mounting arrangement for the second conductive member provides a second current loop defined by the second leg portion of the first loop and a third leg portion. The magnetic forces in the first current loop, which tend to pivot the second leg portion towards the third leg portion, are opposed by magnetic forces in the second current loop. Compression spacers provide parallel current paths which reduce the magnitude of current flowing through a pivotable joint of the relatively stationary contact assembly.

Abstract: The handle of a circuit breaker is blocked from movement to the off positiion, when the contacts are welded closed, thereby preventing rotation of the common cross-bar on which contact arms carrying the movable contacts are mounted, by an interlock which includes radial extensions on the arms of a pivoted handle yoke which radially engage projections on the cross-bar.

Abstract: In an improved panel interior assembly of the type in which elongated bus bars are snap-fit into an insulating support structure a plurality of integrally molded pins are attached to the insulating support structure positioned to extend through holes in a pan to which the insulating support structure is to be attached. These pins are ultrasonically staked to securely hold the insulating support structure and bus bars attached thereto on the pan.

Abstract: Control circuitry is disclosed for electrical starters, contactors and the like having a starting winding and a serially coupled holding winding wherein the holding winding is shorted until the separable main contacts have closed which includes circuitry which obviates the need for relatively precise sensing of the position of the separable main contacts to control the holding winding. In one embodiment of the invention, the unshorting of the holding winding is delayed a predetermined number of cycles after the separable main contacts have closed to avoid the necessity of relatively accurate mechanical sensing of the position of the separable main contacts. In this embodiment a relatively less expensive field effect transistor or the like is used to short out the holding winding until the separable main contacts have closed. This allows the use of a relatively less expensive limit switch with a substantially smaller DC capability.

Abstract: A circuit breaker includes an interlock which prevents movement of the handle to the off position when the contacts are welded closed. The interlock includes a pair of floating links which jam between slots in arms of the yoke of a spring powered operating mechanism which carries the handle, and recesses in the rotatable cross-bar carrying the movable contact arms. The recesses are offset from the rotational axis of cross-bar so that an attempt to move the switch to the off position generates a moment which will break open lightly welded contacts.

Abstract: A limiter circuit utilizes an RC circuit to provide negative feedback of the average value of the output signal of an amplifier, which may be an op-amp or a comparator, to the inverting input of the amplifier. The midpoint of the amplifier supply voltage is applied to the non-inverting input so that the amplifier operates in the linear range. This, combined with the elimination of the effects of offset produced by the negative feedback, results in a limiter circuit with increased sensitivity to small input signals and therefore extended dynamic range. Where a following circuit would be adversely affected by noise, hysteresis provided by positive feedback applied to the non-inverting input of the amplifier causes the limiter circuit to oscillate, at a frequency determined by the magnitude of the positive feedback and the time constant of the RC circuit providing the negative feedback, for input signals having an amplitude below a threshold set by the magnitude of the positive feedback.

Abstract: An interlock, for a pair of electromagnetic switches, includes operating members which are pivoted by movement of armatures of the switches between off and on positions. Ring segment cams are carried by the respective operating members along arcuate paths which intersect such that movement of one switch out of the off position mechanically blocks movement of the armature of the other switch out of the off position. For side by side electromagnetic switches, the operating members are directly confronting. For other arrangements of the switches, such as one above the other, the operating member of one switch includes a first pivot member pivoted by the associated armature, and a second pivot member on which the ring segment cam is carried, confronting the second operating member, and connected to and pivoted with the first pivot member by a connecting member.

Abstract: A side plate for use in a knockdown, electric wiring box to form a side wall of the wiring box. The side plate includes a retaining member at a first extremity of the side plate for engagement by interpenetration with a mating component on the electric wiring box to form a releasable interlock retaining the first extremity to the electric wiring box. A screw stop, projecting from the side plate in a direction opposite the electric wiring box is provided at a second extremity of the side plate to form a positive and firm abutment for a locking screw threadedly engaged in the electric wiring box, overlapping the side plate to achieve an interference relationship therewith and lock the second extremity of the side plate to the electric wiring box. The invention is also directed toward an electric wiring box incorporating the novel side plate.

Abstract: A vertical bus bar arrangement has three phases, each consisting of two U-shaped members disposed to form an H-configuration and a flat, rectangular bar spaced away from and on each side of the H-configuration. Insulator members are arranged between the bus bar arrangement and the brace members. The insulator members have extended portions raised away from the surface of the bus bars for receiving part of the two interconnected barrier members. The insulator members and a substantial portion of the barrier members form a labyrinth between phases. The barrier members have knockout portions for the electrical connections of the bus bars, and also portions for covering the raw edges of the bus bars in the areas through which the runbacks extend. The crossbars are connected to the bus bars by at least two connectors, one of which extends in the gap formed by the connectors of the bus bars, and one of which extends alongside the flat bar and parallel to the first connector.

Abstract: An operating mechanism for the operation of a circuit breaker by movement of a toggle handle in a vertical plane and a switch handle movable in a horizontal plane, and comprising a housing, a shaft, a toggle handle and a gear plate mounted on the shaft, and a pivot plate. The pivot plate has slots arranged in an arcuate path, a butterfly cut-out section which receives and engages the switch handle of the circuit breaker, and an arcuate opening and pin arrangement for guiding the pivot plate in its pivotal movement. The gear plate has a flat portion and an arcuate portion with gear teeth. These gear teeth on the gear plate enter the slots in the pivot plate to rotate the pivot plate for operation of the switch handle. Rotation of the pivot plate is generated by movement of the toggle handle in a vertical plane.

Abstract: A non-metallic enclosure for electrical apparatus has a housing and cover with a door pivotably mounted on the cover. A hood is attached to the housing such that when the door is attached to the cover and the cover is attached to the housing at least one pivotable connector will be behind the hood so that the door can only be nondestructively removed by removing the cover from the housing. Electrically conductive connectors and resilient snap-in members are preferably molded into the housing to secure bus bars and neutral bars to the housing.

Abstract: A 12-pulse converter of lower rating and minimal current harmonics is obtained with an auto-connected regular hexagon transformer including a delta winding in its center.

Abstract: A molded case circuit breaker is provided with a pivotally mounted contact arm assembly, formed as a clinch joint. The contact arm assembly is a bifurcated assembly formed from two coextensive members fastened together at one end defining a surface for carrying a movable main contact. The other end of the members is bent outwardly defining spaced apart arm portions for receiving a pivot bracket. The pivot bracket is provided with an aperture and aligned with apertures in the spaced apart portions for receiving a pivot pin and defining a pivot axis. The pivot bracket is rigidly connected to a load conductor. The current that flows through the contact arm is transferred to bosses integrally formed adjacent the apertures in the pivot bracket. Screw adjustable spring members are provided for adjusting the friction and the electrical resistance between the contact surfaces of the contact arm assembly and the bosses.

Abstract: A molded case circuit breaker includes an interlock which prevents the operating handle from being placed in the off position after the main contacts have been welded together. By preventing the operating handle from being placed in an off position during such a condition, the operating handle will indicate the correct status of the main contacts and the operator will be made aware that the main contacts are welded together.

Abstract: The handle of a circuit breaker is controlled manually by sliding a linkage member right, or left, upon a flat surface of the housing of the circuit breaker. The linkage member is at one end pivotally attached through a knurled pin to the handle and, at the other end, a handhold portion is provided with a recess admitting a finger, or thumb, to push or pull the linkage member and actuate the circuit breaker through its handle.