Abstract: A plane change connector assembly is provided which connects electrical busbars which are in different planes. The assembly includes a connector which has at least one coupling flange cantilevered from one side of a planar joining member. A second coupling flange is cantilevered from the other side of the planar joining member in a different plane from the first coupling flange and preferably, in a plane at a right angle to the plane of the first coupling flange. The connector can be used as part of an assembly for connecting multiphase systems having multiple co-planar busbars for each phase. In this preferred form, the connector is provided with multiple coupling flanges, and a connector is associated with each phase of the system. The co-planar busbars for each phase are connected with plates which in turn engage the first coupling flanges of the connector.

Abstract: 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.

Abstract: A snap action operating mechanism for electrical switches and the like includes a hollow cylindrical housing closed at the ends. A rod extends through one end and is slidable within the housing, while the opposite end of the housing is connected to the switch to be operated. A trip bar projects radially outward in diametrically opposed directions from the rod through longitudinal slots in the housing. A pair of compression springs are disposed within the housing, one on each side of the trip bar. Latch units, each comprising a pair of pivoted latch members, alternately engage opposite ends of the housing to restrain movement of the housing in that direction. Thus, initial longitudinal movement of the rod in the direction of the engaged latch unit results in compression of one of the springs until the trip bar engages a camming surfaces on the engaged latch members, and rotates them clear of the housing. The housing is then accelerated rapidly by the energy stored in the compressed spring.

Abstract: A bi-directional communication and control system includes a common network line over which messages are transmitted in a specific message format and a plurality of hardware based digital IC's which are coupled to the common network line and are arranged to receive messages from and transmit messages to the network line in the specific format is taught. Specifically, a multipurpose two-way communication device is taught which is connected to one of the digital ICs, the device being operable in a master mode in which the device interfaces an external controller to the network line through the connected digital IC so that the external controller can act as the master controller for the plurality of digital ICs coupled to the common network line.

Abstract: A high voltage circuit interrupter, having telescopic tubular insulating and conducting casings, contains an expulsion end sealing construction which hermetically seals and controls the expulsion rate of the interrupter. The expulsion end includes a sleeve, a thin, rupturable diaphragm affixed against the sleeve by cyanoacrylate cement, and an end cap. Epoxy cement is applied into the cap so that the space between the diaphragm and the end cap are filled forming a sealant layer therebetween. A main ferrule secures the strain element, and an auxiliary ferrule secures both the main ferrule and the end cap onto the end of the tubular insulating casing.

Abstract: A molded case circuit breaker is provided with a quick change current transformer assembly. The current transformer is used to sense overcurrent conditions and apply a signal to an electronic trip unit to trip the circuit breaker. The quick change assembly includes an insulated removable plate located adjacent an open cavity in the housing in which the current transformer is located. The current transformer is donut-type disposed about a load-side conductor located in a cavity in the housing rigidly fastened to the circuit breaker frame. In order to replace a current transformer, the insulated backplate is removed. Next the load-side conductor is unfastened and removed from the circuit breaker housing. The current transformer is then removed from the circuit breaker housing. In order to install a new current transformer, the steps are reversed. A force transmitting spacer is disposed adjacent a bight portion of a shunt, connected between a pivotally mounted contact arm and a load-side conductor.

Abstract: A power drive mechanism for a circuit breaker handle which includes a reversible electrical motor, a carriage assembly and a cooperating slide plate assembly mechanically coupled to the motor shaft. The carriage assembly includes a pivotally mounted L-shaped lever, interlocked with the circuit breaker operating handle for driving the operating handle to an on position or alternatively to an off position on command. Microswitches are located at both the on position and the off position for controlling operation of the motor. The microswitches are actuated by the slide plate assembly which, in turn, is driven by the carriage assembly. The slide plate assembly is slidably mounted with respect to the carriage assembly with one or more wave washers. The slide plate assembly provides mechanical damping for the carriage assembly to minimize damage to the microswitches.

Abstract: An adjustable starter baseplate assembly is disclosed for use in mounting a contactor unit and an overload relay unit. The baseplate assembly comprises a support plate and an adjustable extension plate. The support plate has a first mounting surface which has a plurality of threaded openings thereon at least two of which will match the mounting footprint of a contactor unit to be mounted thereon. The extension plate has slots therein which are aligned with threaded mounting holes on a second mounting surface of the support plate. An electrical component, preferably an overload relay, is mounted onto the extension plate and the same screw fasteners are used to mount the overload relay to the baseplate assembly and to secure the extension plate in the appropriate position onto the support plate. The assembly is adjustable such that it may be used with a variety of sizes of housing enclosures.

Abstract: 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.

Abstract: A motor controller or contactor is disclosed which utilizes a non-saturating current transformer for sensing the amount of current flowing in the electrical conductor connected to the contactor. The current sensor is made of homogeneous sintered powdered metal having evenly distributed microscopic air gaps therein which increase the reluctance of the magnetic circuit but resist the influence of stray magnetic flux. This increased reluctance prevents magnetic saturation over a wide range of input current and allows the secondary of the transducer to produce a voltage which is proportional to the derivative of the primary current, that is the current being sensed by the transducer. The aforementioned voltage is linearly proportional to the derivative of the current over a wide range of primary current values. This voltage is integrated to produce an output signal which is directly proportional to the aforementioned primary current over the wide range of current values.

Abstract: In place calibration of the permanent on-line force measurement system of a rolling mill is performed by replacing the working rolls with dedicated calibration rolls, which can be scrap working rolls. Discontinuities formed in the cylindrical surfaces of dedicated calibration rolls, such as flat surfaces or preferrably flat bottomed longitudinal grooves, are engaged by interface members which also engage confronting flat surfaces or grooves in calibration load cells inserted between the dedicated calibration rolls. The interface members, which are made of a softer material than both the calibration rolls and the load cells, cold flows to evenly distribute the load and eliminate the need for precision machining of the interfaces. The dedicated calibration rolls can also be fixed, such as by welding, to dedicated calibration roll chalks which mount the calibration rolls in the mill housing to further prevent roll rotation and ejection of the calibration load cells.

Abstract: In a communication and control system, an improved interface between a digital IC and its associated microcomputer is provided wherein a serial shift register in the digital IC is used to store the message bits of a received message and control of the shift register is transferred to the associated microcomputer as soon as the interface is set up so that data stored in the register is not overwritten by another received message. A busy signal is also supplied over one line of the interface only during periods when the digital IC is actually receiving or transmitting a message.

Abstract: Briefly, the present invention relates to a molded case circuit breaker. The molded case circuit breaker includes at least one pair of separable main contacts, mounted on upper and lower contact arms. One end of the lower contact arm is formed as a U-shaped portion defining depending leg portions and a bight portion forming a reverse current loop. Disposed adjacent the lower main contact on the lower contact arm is an arc runner assembly which directs the arc resulting from a separation from the upper and lower main contacts into an arc chute to quench the arc. The arc runner assembly includes an arc runner and a support block. The arc runner may be formed from steel and is carried by the support block, disposed between depending leg portions of the lower contact arm. The support block is formed from an electrically insulating material, such as a glass polyester.

Abstract: A molded case circuit breaker is provided with a two piece cradle assembly having a cradle portion and a heat-treated portion. The heat-treated portion forms the latch and reset surfaces. The cradle portion is integrally formed from a pair of spaced apart cradle-shaped arms joined together by a connecting portion. The heat treated portion is securely fastened to the connecting portion to form the two piece cradle assembly. A hold down slidably carries a handle barrier with respect to the cover and closes a centrally located aperture in the cover for all handle positions. The handle barrier prevents arc products resulting from a separation of the main contacts from escaping through the centrally located aperture in the cover. Stops are provided in one or both directions to prevent misalignment of the handle barrier with respect to the operating handle. A cover interlock is also provided to prevent the cover from being removed when the circuit breaker is in an "on" position.

Abstract: A molded case circuit breaker is provided with a magnetic trip device which allow for a relatively wide range of adjustment. The magnetic trip device allows the magnetic air gap to be varied as well as the spring force on the plunger. Additionally, the magnetic trip device allows the force required to rotate the trip bar to be varied. By providing a means for adjust the force required to rotate the trip bar, the adjustment range of the magnetic trip device can be substantially enhanced. The molded case circuit breaker includes at least one pair of separable main contacts. The separable main contacts are mounted on upper and lower contact arms. The lower contact arm may be rigidly mounted to a line side conductor, while the upper contact arm is pivotally mounted to a load side conductor. The upper contact arm is mechanically coupled to an operating mechanism. A pivotally mounted trip bar is operatively coupled to the operating mechanism.

Abstract: 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.

Abstract: A trip interlock assembly trips a circuit breaker any time the circuit breaker is removed from its panel mounting. The trip assembly is adapted to be disposed about a load side terminal and cooperate with the circuit breaker tripping device. In one embodiment, the trip assembly includes a housing and a spring-loaded actuation arm, disposed generally perpendicular to the circuit panel surface. The actuation arm is formed with a cam surface which cooperates with a trip pin adapted to actuate said circuit breaker tripping device. The trip pin acts as a cam follower and rides along the cam surface formed in the actuation arm. When the actuation arm is in an inward position the trip pin is in a normal position. However, when the circuit breaker is removed from the panel, the actuation arm under the influence of a biasing spring moves outwardly. This causes the cam surface on the actuation arm to actuate the trip pin to trip the circuit breaker.

Abstract: A multiphase circuit breaker has a magnetic trip assembly which includes an adjusting bar slidable longitudinally to simultaneously adjust the bias applied by individual torsion springs to the rotatable armature of the magnetic trip assembly for each pole over a range of trip currents from a high setting to a low setting. Adjusting screws carried by the adjusting bar provide for adjustment of the gap between the armature and stationary magnetic structure independently at the high and low settings separately for each pole. An additional set of adjusting screws can be inserted in the adjusting bar to provide a single adjustment of the gap over the full range of spring bias settings.

Abstract: A microprocessor based circuit breaker has a removable rating plug which provides a reference for the current rating of the breaker. The removable rating plug also has an EEPROM to which the microcomputer of the circuit breaker writes for storage, the number of operations of the circuit breaker operating mechanism and a trip history of the breaker in the form of a count of the number of trips weighted by the magnitude of the trip current. The rating plug is periodically removed and plugged into a portable programmer which selectively displays the number of operations and operating history of the circuit breaker. The programmer clears this operating data when recorded and can write into the EEPROM the style and serial number of the circuit breaker with which the rating plug is to be used.

Abstract: A high voltage circuit interrupter, having telescopic tubular insulating and conducting casings, contains an expulsion end sealing construction which hermetically seals and controls the expulsion rate of the interrupter. The expulsion end includes a sleeve, a thin, rupturable diaphragm affixed against the sleeve by cyanoacrylate cement, and an end cap. Epoxy cement is applied into the cap so that the space between the diaphragm and the end cap are filled forming a sealant layer therebetween. A main ferrule secures the strain element, and an auxiliary ferrule secures both the main ferrule and the end cap onto the end of the tubular insulating casing.