Abstract: An arcing fault protection system for a switchgear enclosure includes a switching device for rapidly diverting current from the source bus of an electrical distribution system in response to the detection of arcing faults in the system. The switching device, which may comprise a mechanical switch, a solid-state switch or hybrid device, quickly diverts current carried on the source bus to effectively extinguish arcing fault currents present in the distribution system, preventing the generation of gases at high pressures and/or temperatures so as to protect the switchgear equipment from damage.

Abstract: An arcing fault protection system for a switchgear enclosure includes a grounding device for rapidly grounding the source bus of an electrical distribution system in response to the detection of arcing faults in the system. The grounding device, which may comprise a mechanical switch, a solid-state switch or hybrid device, quickly diverts current carried on the source bus to ground to effectively extinguish arcing fault currents present in the distribution system, preventing the generation of gases at hazardous pressures and/or temperatures so as to protect the switchgear equipment from damage and to prevent injury to operating personnel.

Abstract: A sliding contact comprises a stationary contact member having an opening extending therethrough and a movable contact member, at least a portion of which is disposed within the opening. Conductive bearing means are disposed within the opening between the stationary contact member and the movable contact member for supporting the movable contact member within the opening and for maintaining an electrical connection between the movable contact member and the stationary contact member. Preferably, the conductive bearing means comprises a plurality of conductive ball bearings.

Abstract: A puffer interrupter with arc energy assist employs a cylinder which moves telescopically over a stationary piston. The cylinder carries a movable contact structure and an insulation nozzle and moves within an insulation chamber. The cylinder has an extending flange slidably sealed to the interior of the housing. The flange has a surface which faces the gas volume which is expanded during arc current interruption so that a force is applied to the cylinder which adds to the force of an operating mechanism connected to the cylinder in order to operate the interrupter to its open position.

Abstract: A liquid SF.sub.6 circuit interrupter is disclosed which employs only one moving piston, eliminating the need for tie rods used in conventional liquid dielectric interrupters to connect two pistons in tandem, which tie rods were possible paths for flashovers. The moving contact is mounted at one end of a movable piston device in the other end of which is formed a bore that fits over a stationary piston secured to the housing. The interior of the bore communicates with the remainder of the interior of the housing via holes adjacent the moving contacts. When the movable piston device is moved to open the interrupter, the compression of fluid in the interior of the bore causes it to flow through the holes and through the arc region. The movable piston device also includes a piston member having one face exposed to the liquid dielectric in the housing and having an opposite face exposed to a lower ambient pressure. A net force tending to bias the interrupter into the open position results.

Abstract: A liquid SF.sub.6 interrupter is disclosed comprising a housing containing a pair of pistons operable for movement in tandem. Stationary and movable contact assemblies are disposed between the pistons. At the beginning of the opening stroke of the interrupter, the pistons are caused to begin moving in the same direction as the movable contact. The pistons and housing are so shaped and dimensioned that the movement of the pistons produces a high pressure and a low pressure region located respectively relatively near the stationary and the movable contacts. This causes SF.sub.6 to flow across the area between the contacts. An arc between the contacts heats the liquid adjacent it, increasing the liquid pressure. The pistons are so dimensioned that the pressure rise accelerates them, which in turn further increases the pressure differential and the flow of SF.sub.6 across the arc region. A small clearance is left between the pistons and the housing, so that no sliding seals are required.

Abstract: A quick open and close disconnect switch suitable for use in EHV and UHV systems is disclosed. In addition to a conventional main moving contact and a conventional mechanism for operating it, a preferably much smaller, lighter auxiliary moving contact is provided. The main moving contact is moved away from (or toward) the stationary contacts to open (or close) the switch. While this is happening, the auxiliary moving contact is retained by means of a latch arrangement in its position engaged with (or remote from) the stationary contact. When the main moving contact has traversed a predetermined portion of its path, the auxiliary moving contact is released and is moved suddenly, with great speed, to its open (or close) position. The motive power for the auxiliary moving contact is preferably provided by a power spring which is compressed by the movement of the main contact.

Abstract: A high voltage, high power circuit interrupter uses liquid SF.sub.6 in a puffer type arrangement. The cooperating contacts are surrounded by a nozzle and an upstream and a downstream piston, which are moved by a constant force-operating mechanism, move liquid SF.sub.6 between the cooperating contacts when they separate, in order to interrupt the arc between the contacts. The interrupter requires a relatively low volume of SF.sub.6 and a constant pressure is generated in the liquid during interruption. The interrupter ratings are adjusted by varying the differential pressure across the nozzle, and by changing the base-operating pressure.

Abstract: A moving contact structure for an arc spinner type of interrupter is provided with a flow channel which communicates with the arcing region and permits the flow of arc plasma away from the arcing region during interruption. The flow channel in one embodiment of the invention is defined by openings near the end of a hollow elongated movable contact part. In a second embodiment of the invention, a restricted volume is provided behind the arcing contact and this volume is expanded during the interruption process to produce a negative pressure during the interruption process which will promote the flow of arc plasma away from the arc space and into the region behind the arcing contact.

Abstract: A high speed actuating mechanism for operating the contacts of a circuit interrupter has an operating shaft connected to the contacts and to an operating piston. The operating piston has a short-circuited conductive ring or repulsion disc which is closely coupled to a lenz coil operator in one position of the actuating mechanism. The operating piston also has an enlarged diameter sealing protrusion which seals against an annular seal which is concentric with the lenz coil operator. Both the lenz coil and the sealing ring are spring-mounted to have several degrees of resiliency to enable proper relative location of the repulsion disc and the lenz coil and proper relative location of the annular seal and contact protrusion to control seal penetration and to enable compensation for contact erosion when butt-type contacts are used.

Abstract: A high power a-c circuit breaker having substantially no arcing during interruption consists of two identical switching circuits in series which each include a main high speed switch connected in parallel with a series-connected diode and high speed isolating switch. The diodes of each of the switching circuits oppose one another in polarity. Current flow through the circuit breaker is normally through the closed main high speed switches. A polarity-sensitive operating circuit is provided to open the appropriate high speed switch just before a current zero and to transfer forward current through its related diode. This diode blocks a current reversal, and the associated series-connected isolating switch is opened just after current is commutated into the diode, and at or before the current zero time is reached and while the diode is blocking.