Abstract: A corona tube is provided wherein the tube is flexible so that it can fit on any three dimensional container rim. The tube can be a flexible steel tube which is a standard commercial variety of corrugated steel tube which is usually used to contain wires or the like. The tube has a slotted edge along its length, is cut to a length to the periphery of the rim and bent in the shape of the rim. The slot of the flexible tube is placed over the edge of the rim and thereafter the tube can be welded to the rim.

Abstract: A reclosing system for d-c feeder circuit breakers used on transit systems is disclosed. Circuit breaker closure is prevented when the feeder circuit voltage is in a predetermined voltage range and when the feeder circuit impedance is less than a given value, which is less than the impedance which would be presented by a parked train in a deenergized portion of the transit rails. A Wheatstone bridge is inserted into the circuit during the load impedance measurement. The Wheatstone bridge circuit is compensated for positive or negative rail return voltage. The automatic reclosing scheme is locked out after two closures of the circuit breaker followed by automatic tripping within six minutes, or by twelve load impedance measurements, which are performed within three minutes and which all fail to lead to a circuit breaker closure.

Abstract: A cylindrical housing for a high voltage circuit breaker is filled with sulfur hexafluoride and receives three parallel elongated puffer interrupters arranged with their axes on the apices of an equilateral triangle. A single triangular support plate receives one end of each interrupter and supports them in cantilever. The triangular plate is fixed to the housing by thin steel straps affixed to respective apices of the plate. Filter bags in a removable tray are disposed along the horizontal bottom of the housing. Bushings enter the tank through openings in the tank wall. The openings receive slotted flexible tubes which wrap around the slot edges to serve as corona rings. The bushings each have an integral central conductive stud and conductive end plate.

Abstract: A multi-pole circuit breaker has interrupters contained in respective housing sections which have two bushings extending perpendicularly from either end of the housing section. Each housing section is segmented at its center so that the two halves which are defined can rotate relative to one another whereby the bushings extending from the housing halves can have different angular relationships with respect to one another and the bushing-free ends can have different spacings. The circuit breaker can be used as an indoor or outdoor circuit breaker with common parts but the bushing spacing is altered by adjusting the angular relationship of the bushings relative to one another.

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 self-powered ammeter is disclosed. A metering circuit receives an a-c current to be tested and then generates a d-c voltage whose magnitude is proportional thereto. A display circuit receives the d-c metered voltage and provides a visual indication of the magnitude of the measured current. The current to be measured also drives a current transformer which, in turn, has an output burden circuit which produces a regulated power supply for the metering and display circuit components.

Abstract: A gas-insulated high voltage cable for submersion in water has an increased internal gas pressure in the interior of the outer cable housings which are to be at a depth greater than 100 feet. The wall thickness of the housings may be the same as that of housing sections which are at external ambient pressure or at an external pressure given by immersion in water at a depth of less than 100 feet. The increased pressure is applied to the housings through the central conductor which is continuous for the cable.

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 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: An arc spinner interrupter is provided with a chamber above the coil which contains a piston of ferromagnetic material. The chamber communicates, through a channel through the center of the coil, with an arc extinguishing region. The arc extinguishing region contains the movable contact and cooperating arc runner disk of the arc interrupter. During arc interruption, the magnetic field produced by the coil causes the arc between the movable contact and arc runner to circulate in the usual manner in a relatively static gas-filled arc extinguishing volume. The magnetic field of the coil also produces an attractive force on the ferromagnetic puffer piston and causes compression of the gas-filled volume above the coil and causes the movement of cool gas through the channel into the arcing region.

Abstract: A sensing circuit is disclosed for simultaneously and continuously monitoring the impedance of a trip coil of the type used to actuate synchronously operated circuit breakers, and the charge on a capacitor used to power the trip coil. The sensor comprises a circuit including the trip coil, the capacitor, a large resistance and a photo-diode connected together in series. A d.c. voltage is continuously applied across the capacitor, maintaining it charged and causing a constant direct current to flow through the other three components. The magnitude of the current will fall below a predetermined threshold value if either the capacitor voltage, which is proportional to the charge stored on the capacitor, falls below a certain level or the resistance of the trip coil rises above a certain level. The photo-diode produces a light signal representative of the current therethrough.