Westinghouse Electric Corporation

Eaton Corporation

Norman Davies

Francois Jean Marchand

Peter J Theisen

George Alfred Hodkin

Stanislaw A Milianowicz

Walter V Bratkowski

Ronald E Vaill

Nagar J Patel

Walter Oliver Jenkins

Trevor Brian Marshall

Daun Bhasavanich

James D Smith

John Joseph Shea

James Jeffery Benke

James Leo Lagree

Joseph J Matsko

Richard A Johnson

Edward J Klimek

Fred Bould

Paul Bottegal

William R Crooks

John F Perkins

Glenn Arthur Calhoon

John Dennis Petrisko

Robert E Wobrak

Robert J Rinefierd, Jr

Semahat D Sinharoy

Charles K Wallace

Trevor Brian Marshal

Allen G Filson

Morley P Langley

Howard C Peppel, Deceased

Michael C Valenta

Francois J Marchand

Protection is provided for servicing a distribution bus by grounding the line side of a circuit breaker through which the distribution bus is fed and then closing the circuit breaker. The trip unit of the circuit breaker includes logic, in addition to the normal protection logic, which opens the circuit breaker main contacts without delay if current is detected upon closing of the grounded circuit breaker. However, if the grounded circuit breaker has been closed for a selected period of time and then current is detected, the distribution bus is kept at zero potential by not operating the breaker. A breaker auxiliary switch with a mechanical delay provides the indication of the selected time interval after closing the circuit breaker.

Apparatus and method for servicing a distribution bus

A load connector module for connecting a multi-phase load to a circuit interrupter which includes all the multi-phase connectors, a current transformer for each respective phase, and a voltage transformer coupling, in an integral, solid, insulated unit.

Integral load connector module

A compact power circuit breaker has a molded insulative casing providing the structural support and electrical isolation for the pole mechanisms mounted in cavities in the casing and the operating mechanism mounted to the front of the casing. A grounded barrier between the pole mechanisms and the operating mechanism protects the operator actuating push buttons controlling the operating mechanism and accessible through a molded insulative cover. Preferably, the grounded barrier is sandwiched between a rear section of the molded casing containing the pole cavities and a forward section to which the operating mechanism is secured. The grounded barrier is connected to an electrically conductive pan extending under the molded insulative casing which also houses electrically grounded linkages coupling the operating mechanism to the vacuum interrupters of the pole mechanisms. A vented air gap between the rear section of the molded insulative casing and the grounded barrier minimizes erosion of the molded insulative casing in the event of an arc penetrating the casings to the grounded barrier.

Power circuit breaker having molded insulative casing with a dead front

A compact switchgear system employing a number of modular components that plug into their mating interface and are maintained in electrical isolation employing solid insulation in a manner that substantially shields the electrical conducting portions of the assembly from contact with lower voltage portions of the system. The assembly is primarily made up of five modules. A multi-phase load connector having integral current monitoring transformers for each of the respective phases; a voltage monitoring transformer which plugs into the load connector; an in-line actuator and vacuum interrupter module, provided for each phase, which plugs into the load connector; a three position vacuum switch connected between the vacuum interrupter module and the line or ground; and an electronic control module which receives inputs from the current and voltage monitors, circuit relays, vacuum interrupter/in-line actuator module, and temperature sensors, and provides programmed, controlling outputs to the in-line actuators of the respective vacuum interrupter modules.

Modular, miniaturized switchgear

Power circuit breaker with air gap between molded insulative casing and grounded barrier insulating operating mechanism

A modular three position vacuum isolator switch that is operable to connect a stationary contact to either of two moveable contacts or an intermediate position which is out of electrical engagement with either of the moveable contacts. One of the moveable contacts is grounded and the other is connected a power source. The stationary contact is connected to two electrical connectors. One of the two electrical connectors is connected to a breaker and the second is connected to a corresponding input on a second similar isolator switch model, which itself is connected to a second line source. The stationary contact is connected to the circuit interrupter for connecting the circuit interrupter to either of the two line sources, to ground, or to isolate the circuit interrupter by placing the isolator switch module in the intermediate position.

Isolator switch

Electrical switching apparatus for an electric distribution system in which the apparatus has an insulative cover on it and a conductive metal layer on the inside of the cover, which is connected to ground.

Insulative cover for electrical switching apparatus for electric power

Operation of a medium voltage spring powered circuit breaker is analyzed by applying a recording medium in the form of an adhesive backed tape to a selected driven part of the operating mechanism. A marking instrument is held in contact with the recording medium at a fixed point by a fixture in the form of a template secured to the circuit breaker frame. When the charged closing springs of the operating mechanism are released, the marking instrument produces a trace on the recording medium which is then analyzed to provide a quantitative evaluation of switch operation, including overtravel of the selected driven part.

Apparatus and method for testing spring powered switches

Effective arc-quenching is desired for current interrupters as defined to include circuit breakers, contactors, fuses and the like under conditions of operation where an electrical arc is produced that must be quenched to eliminate an undesirable current flow. An improved mode of arc-quenching coatings comprising urethane, melamine and acrylic based resin compositions containing inorganic nitrides such as boron nitride, aluminum nitride and silicon nitride are found to be effective as arc-quenching materials for current interrupters. Other coating compositions comprising urethane, melamine and inorganic nitrides mentioned above and high nitrogen organic compounds such as urea, hydantoin, allantoin, guanidine carbonate, guanine, melamine cyanurate and 1,3-diphenyl guanidine are also found to be effective as arc-quenching materials for current interrupters.

Thermally conductive, insulating, arc-quenching coating compositions for

A circuit breaker, and method of constructing same, in which a levering-in mechanism may be added after the circuit breaker has been assembled. The circuit breaker includes a chassis having first and second side plates which define upwardly open slots, which enable the levering-in mechanism to be 'dropped in' to the correct position of an assembled circuit breaker, with bottom portions of the slots functioning as half bearings. First and second retainer plates with downwardly open slots are respectively attached to the first and second side plates, to complete the half bearings and hold the levering-in assembly. The levering-in mechanism includes a threaded shaft having a traveling nut, with a bushing on the shaft being held radially, but not axially, by a bracket member, with the bushing also functioning as a non-stress stop for the traveling nut. New interlock arrangements are also associated with the levering-in mechanism, including interlocks which: (1) prevent access to the levering-in mechanism, (2) place the circuit breaker in a trip-free condition, and (3) discharge closing spring, in response to predetermined conditions.

Drawout switchgear with improved levering-in mechanism and interlock

A circuit breaker contact operating structure characterized by a circuit breaker operating mechanism having separable contacts of which one is mounted on a contact carrying arm. The arm being mounted on a one leg of a U-shaped flexible conductor. A guide link is pivotally mounted and connected to the arm to maintain the contacts in alignment during their separation. The operating mechanism having a latch for latching the arm in the closed-contact position of the arm and having a trip device for unlatching the latch in response to an overcurrent condition. The mechanism link is so placed on the contact arm structure as to effect a blow-on force on the contact structure during the duration of high overcurrent. At a preset current level, the mechanism link is prevented from applying the balancing force to the contact structure, thus allowing the blow-off forces due to the current in the contact structure to separate the contacts rapidly, and to effect current limitation and subsequent circuit interruption.

Circuit breaker contact operating structure

A circuit breaker characterized by first and second main contacts and first and second arcing contacts. The first main and arcing contacts are mounted on a first contact carrying arm. The second arcing contacts are mounted on a second contact carrying arm. The second main contacts are mounted on a third contact arm. The first contact carrying arm is mounted on a first pivot and the second and third contact carrying arms are mounted on a second pivot. A spring for biasing the second main contact against the first main contact and in the closed position. A second spring for biasing the second arcing contact against the first arcing contact until after the first and second main contact separate.

Circuit breaker with low voltage contact structure

An electrical boot for the bus bar joints of electrical metal-clad switchgear is taught. The boot is formed by taking a piece of heat shrinkable material, disposing it over a joint or similar construction, heating and shrinking the material so that it shrinks to the shape of the joint or construction in question while at the same time, providing on two opened edges thereof a clamped chill bar which does not allow those portions to cohere to each other so that the boot may be removed after the formation process and easily disposed upon a bus bar joint located within the tight confines of a metal-clad switchgear cabinet. The process may be utilized to form metal-clad switchgear having bus bars with a heat-shrunk insulating boot on the joints thereof. Furthermore during the production process, a bolt envelope simulating template or jig may be utilized to fill out the area on the finalized boot which roughly corresponds to the outer dimensions of the bolt and nut arrangement.

Method for insulating conductor joints particularly bus bars and

An enclosure structure for housing switchgear apparatus (such as circuit breakers) is fabricated from a pair of sheet metal panels that are held in precisely-spaced upstanding relationship by a plurality of metal cross-struts of U-shaped cross-section which mechanically interlock with apertured portions of the panels and are held in such position by triangular-shaped metal gussets which overlap and are bolted to adjacent portions of the cross-struts and panels. The cross-struts are provided with longitudinally protruding tangs at each end that are slip-fitted into and interlock with slot apertures in the panels. The width dimension of the finished enclosure structure is precisely controlled by positioning tabs on the ends of the cross-struts that are offset from the associated tangs and are drawn into abutting relationship with the inner surfaces of the respective panels when the structure is bolted together. Construction and assembly of the enclosure structure is accordingly achieved without the expensive tooling, jigs and welding operations heretofore required to manufacture such structures.

Enclosure structure for circuit breaker assemblies and similar apparatus

There is provided by this invention a vacuum monitoring device for use in vacuum circuit interrupters comprising a stacked resistor assembly as a voltage divider coupled to an internal shield of the vacuum bottle and a low voltage detection circuit for monitoring leakage currents under abnormal pressure conditions.

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Irwin, PA, United States of America

Norman Davies