Square D Company

Ferdinand E Chabot

Tak M Wong

James P McGinnis

A low resistance electrical connecting assembly, each assembly including a plurality of operably arranged conductive elements, each element comprising a pair of relatively narrow, thin, outwardly convex, conducting contact surfaces supported on opposite sides of a latitudinal plane between them. The outwardly convex contact surfaces of each element are conductively associated to provide parallel current paths between source-side and load-side conductors in contact respectivley with opposite ones of said conductive surfaces of each element. Such elements may be embodied in the form of a helical coil of conductive wire, each ring of the coil constituting one element. Another embodiment may be individual disks of conductive metal arranged in stacking relationship. Any number of other embodiments are possible which provide a plurality of elements as described, thin, outwardly convex conductive surfaces on opposite sides of a latitudinal plane, in closely adjacent side by side arrangement.

Low resistance electrical connecting assembly

A pair of toggle links in a high amperage molded case circuit breaker are driven over center in response to the discharge of a closing spring for pivoting a plurality of blades and closing the breaker contacts. A latch link pivotally connected to the upper toggle link also is engaged by a pivotable latch along an arcuate surface on the latch so that shock forces are transmitted along a radial line of the latch for minimizing inadvertent rotational forces on the latch. The latch release force is rendered dependent on the spring force exerted through the links from the blade overtravel springs and the coefficient of friction of the latch arcuate surface. The force exerted through the links is controlled by an adjustable stop having an inclined surface engaging the pivot connection between the toggle links. Large movements of the stop provide small changes in the inclined surface position relative the pivot connection to provide small changes in the overcenter position. An adjustment assembly controls the distance the latch pivots for disengaging the latch link and a spring associated with the adjustment assembly provides additional shock isolation. Helical coil springs of cadmium copper alloy between the blades and a journal serve to eliminate pigtail connections for the blades.

Contact control arrangement for high amperage molded case circuit breaker

A high amperage molded case circuit breaker utilizing a ratchet adapted to be operated manually or electrically and carrying a spring biased clutch connecting the ratchet to a crank for rotating the crank to tense a helical closing spring. The ratchet is disconnected from the crank when the closing spring has a predetermined tension by a crank operated trip assembly while the closing spring axis passes close to the crank axis to exert a relatively low torque on the crank. The crank rotates a handle positioner to prevent manual operation of the ratchet after the spring is tensed, while electrical operation of the ratchet continues until a switch located in any one of a large variety of positions terminates electrical operation. Shock absorber action for the blades and carriers is provided by a plurality of large area elastomeric plates separated by metal plates and carried by the cover, while rebound and contact closure is prevented by hook members pivoted by the carrier crossbar to engage respective pins carried by one of the blade carriers.

Motor and blade control for high amperage molded case circuit breakers

A circuit breaker having an electronic fault sensing and trip initiating unit which provides increased versatility and ability to coordinate the circuit breaker with other interrupting and protective devices in a wide variety of electrical distribution systems. Electronic circuits and components are provided to vary the ampere rating of the breaker, to adjust current carrying capacity, to provide a long time delay trip, a short time delay trip and an instantaneous trip depending on the amplitude of high fault currents, to provide a ground fault trip, to shorten or lengthen the trip time for short time delay faults and for ground faults, and to provide shunt trip capability. The tripping mechanism is magnetic and mechanical, and includes a plunger movable between a trip and non-trip position controlled by an electronic switch in the electronic circuitry, and a toggle mechanism which is unlatched by the plunger when it moves to the trip position. A bimetal trip mechanism is provided as back-up protection if the ambient temperature not sensed by the electronic circuitry exceeds a pre-determined level.

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Cedar Rapids, IA, United States of America

Ferdinand E Chabot