Abstract: A power factor correction circuit for controlling the inrush current for a power factor correcting capacitor bank in an electrical power distribution system. The circuit includes an inrush current limiting device in series with the capacitor bank. The inrush current limiting device, such as a thermistor, varies its resistance in an inverse relationship to its temperature.

Abstract: A ground fault protection system and method for implementing such is provided for protecting an electrical power distribution system having multiple sources and multiple grounds. A set of current transformers are connected to an interface unit which in turn is connected to a ground fault trip function for a circuit breaker. The interface unit has an output with a low impedance, and the outputs of multiple interface units can be connected in series and feed a single ground fault trip function; thereby tripping the circuit breaker on a ground fault detected by any set of current transformers connected to one of the interface units. Another embodiment utilizes multiple, independent ground fault trip functions in a single circuit breaker. Each ground fault trip function is connected to a set of current transformers, and the circuit breaker will trip if any connected set of current transformers detects a ground fault.

Abstract: The present invention relates to a transformer having a conductive element spiraling along the length of an insulated wire of the coil. When formed into plurality of adjacent turns, the conductive element couples one of the plurality of turns with another of the plurality of turns. The conductive element increases the series capacitance of the transformer circuit. A resistive element may also spiral along the length of the insulated wire to couple one of the plurality of turns with another of the plurality of turns. The resistive element not only increases the series capacitance of the transformer, but also increases the series conductance of the transformer circuit. The increase in the series resistance increases the dampening of the switching resonance.

Abstract: An improved ground fault protection system is provided for protecting an electrical power distribution system having multiple sources and multiple grounds. In accordance with a preferred embodiment, an electrical power distribution circuit having a primary electrical circuit for distributing electrical power from a plurality of sources to a plurality of loads is provided with a ground fault protection circuit magnetically coupled to the primary circuit. The primary electrical circuit includes conventional main and tie buses for distributing power to the loads and switches or circuit breakers for interrupting power from flowing in the buses. The ground fault protection circuit includes current sensors, tripping functions or ground fault relays associated with each circuit breaker and a novel use of an auxiliary transformer. When a ground fault occurs, the ground fault protection circuit is capable of sensing and determining the specific bus in which a ground fault condition exists.

Abstract: A racking assembly is provided for racking a circuit breaker into and out of electrical switchgear having a cell adapted to receive the circuit breaker and a cell door for enclosing the circuit breaker within the cell, the racking assembly includes a shaft having a first end adapted to be coupled to the circuit breaker and a motor coupled to a second end of the shaft for applying a rotational torque to the shaft. An anti-rotation assembly is coupled to the motor for preventing the motor from rotating when it is applying the rotational torque to the shaft.

Abstract: An arc chute for a high voltage load interrupter switch has a pair of closely spaced side walls defining an arc chamber. An inner side of each wall has at least one groove between an open outer end of the chamber and an inner area of the chamber where blade contact is first broken resulting in a electrical arc. The longer axes of the grooves are generally perpendicular to the direction of flow of expanding arc gases that form at an inner end of the chamber when the switch is opened under load. The grooves have a semi-teardrop shaped cross section with the deeper portions of the grooves nearer the outer end of the chamber. As the expanding arc gases flow toward the chamber opening, some gas flows into the grooves which function as vortex generators causing the gases to swirl.

Abstract: The following specification describes a plurality of combination lock cylinders, each of the axially movable tumbler pin type and each having a drive plate initially rotatable in a selected one of two directions by the tumbler operating pins of a respective operating key to control a bolt. A lock cylinder extraction key having tumbler pins universal to each lock cylinder rotates the drive plate in the direction opposite the selected direction to align a slot in the drive plate with a boss in the housing for enabling removal of a respective lock cylinder from its housing.Each lock cylinder has one pair of bayonet slots extending in the selected direction and engaged only by bayonet pins on the respective operating key for enabling rotation of the drive plate only in the selected direction and another pair of axially offset bayonet slots extending in the opposite direction and engaged only by bayonet pins on the lock cylinder extraction key to enable rotation of the drive plate only in the opposite direction.

Abstract: A circuit breaker of a medium voltage roll-in type is connected to an external control system by a plug and associated conductor line. The plug has a handle that is screwed into position to retain the plug in place and to compress a cable spring connected to a flexible cable enclosed in a tube. The compression of the cable spring enables a lever spring, acting oppositely to the cable spring, to move a lever attached to the cable. The lever is connected to move a trip latch that connects to a latch mechanism that opens and prevents closing of the circuit breaker.