Abstract: A power transformer is provided with a housing having a plurality of apertures for receipt of a bushing well of a bushing assembly. Each bushing assembly includes a bushing well adapted to be secured in one aperture of the power transformer, and a bushing adapted to be connected to a terminal in the bushing well to permit the conducting of electric current between the bushing assembly and the transformer. The bushing assembly further includes a connector for connecting the bushing conductor to a terminal positioned in the bushing well. The power transformer may include a cap to cap the unused bushing wells. The cap is, preferably, a plate structure that attaches to the lip of the bushing well and uses the dielectric formed by the air enclosed by the cap and the bushing well to prevent sparking over to adjacent sites and corona discharge, to prevent accidental contact with the live terminal therein, and to guard against contamination of the well.

Abstract: A current transformer for a load switch which has an interior construction tightly engaged with a main bushing therein, allows a voltage in a cable to be detected by forming an engaging hole, communicated with a conductive socket of the main bushing, on a portion of an outer circumferential surface thereof, and which has a current transformer coating casing, made of a rubber material, for thereby diminishing a thickness of the current transformer, includes a core in a ring shape, a coil winding the core, a rubber coating member for tightly covering the core and the coil therein, and coil terminals connected to both ends of the coil. The rubber coating member includes a lower coating part for tightly covering a base unit of the main bushing, and an upper coating part for tightly covering a jaw unit of the main bushing, as well as the coil and the core.

Abstract: A vacuum system (20) includes an enclosure (22) having a vacuum-tight wall (26) and an internally threaded aperture (66) through the wall (26). A tip-off fitting (24) has a base (50) with a bore (52) therethrough, a hollow tube (62) fixed to the base (50) with a vacuum-tight seal, such that an interior (64) of the tube (62) is in communication with the bore (52) in the base (50), and an external thread (58) on the exterior of the base (50). The external thread (58) on the exterior of the base (50) is dimensioned to threadably engage the internal thread (68) on the aperture (66). There is a disengageable vacuum sealant (70) such as a layer of indium metal between the external thread (58) of the base (50) and the internal thread (68) of the aperture (66). The vacuum system (20) is evacuated through the tip-off fitting (24) and sealed by closing off the hollow tube (62).

Abstract: The present invention provides a floating shield for a high voltage bushing. Preferably the bushing is conically shaped and has a composite housing for substantially optimizing the electrical performance of the bushing according to the invention. The floating shield is preferably suspended within the bushing housing by a supporting insulator placed in a low electrical stress region of the bushing. In a preferred embodiment, the supporting insulator is disposed between a ground grading shield and the bushing housing. The composite housing preferably provides a protective inner tube made of a fiber reinforced material and an outer silicone rubber housing having weather sheds formed in a helix on the surface of the housing.

Abstract: An explosion-proof porcelain housing for a gas-filled insulating apparatus includes a hollow porcelain housing body having a tapered inner surface, and a resin lined on the inner surface of the porcelain housing body. The thickness of the resin lining decreases along the tapered inner surface.

Abstract: The apparatus comprises a probe-insulator (3) with an internal cavity, a first system (8/1) that circulates a cold fluid within the cavity (4) of the probe-insulator in order to cool the latter to such a temperature that the external humidity condenses on the external surface, a second system (8/2) for measuring the surface conductivity on the probe-insulator, a third system for activating a washing plant of all insulators installed in the same area when the measured value of said surface conductivity reaches a pre-set critical value; the refrigerating device that produces said cold fluid preferably includes a group of Peltier modules.

Abstract: A corrona test set has at least a reactor and power separation filter placed in an oil-filled conductive tank of a conductive material such as sheet steel. The exciter optionally may also be placed in the same tank enclosure which is of much smaller size than the equivalent voltage rating test set in air. High voltage taken from the circuit passes out of the tank through high voltage bushings. A preferred form of bushing is a quick coupling cable receiving device having an insulator extending into the tank and a frustoconical metallic extension extending away from the tank with a tubular internal wall connected to these respective parts at opposite ends to form a further oil-filled compartment separate from the tank.

Abstract: A feedthrough bushing for a high voltage diode provides for using compression sealing for all sealing surfaces. A diode assembly includes a central conductor extending through the bushing and a grading ring assembly circumferentially surrounding and coaxial with the central conductor. A flexible conductive plate extends between and compressively seals against the central conductor and the grading ring assembly, wherein the flexibility of the plate allows inner and outer portions of the plate to axially translate for compression sealing against the central conductor and the grading ring assembly, respectively. The inner portion of the plate is bolted to the central conductor for affecting sealing. A compression beam is also bolted to the central conductor and engages the outer portion of the plate to urge the outer portion toward the grading ring assembly to obtain compression sealing therebetween.

Abstract: A circuit condition monitoring system for an electrical power distribution system includes a system connector component having an integrally molded test point socket within which a circuit module is received to provide fault current or voltage loss monitoring of a system conductor within the connector. The test point socket provides capacitive coupling to the monitored conductor without the use of a metallic test point, and a ground return to the electrically conductive outer sheath of the connector. An electrically conductive end cap may be provided to cover the projecting end of the module when the module is installed in the socket. Adapters installed on the other end of the module enable the module to be installed on prior metallic contact-type test points.

Abstract: A gas insulated current transformer wherein the metal tank having the inductive unit therein is mounted on the hollow insulating bushing and preloaded with spring pressure so that when the insulating gas within the bushing and the container reaches a predetermined and maximum safe limit the excess build up of gas pressure is allowed to escape between the otherwise sealed contact between the container and the bushing.

Abstract: A voltage transformer for a metal encapsulated gas-filled high-voltage switching system which supplies high accuracy test values even under varying operating conditions of the switching system comprises an active capactive voltage divider in which a cylindrical test electrode and an associated counter electrode are attached by insulating elements to a flexurally rigid cylindrical support element in spaced relationship. In addition, each electrode is attached to the same annular face of the associated insulating element which partially abuts the cylindrical support element.

Abstract: The passage in a wall which separates the interior of the housing of a glandless submersible motor pump from the surrounding atmosphere is normally sealed by an annular seat which is placed against the end face of a muff forming a detachable part of the wall, and by a temperature- and pressure-resistant ceramic sleeve which surrounds an elongated metallic conductor and normally bears against the seat owing to the pressure differential between the interior of the housing and the surrounding atmosphere. If the sleeve is destroyed, a normally confined plunger of the conductor bears directly against the seat to prevent escape of fluid from the pump housing. That end portion of the conductor which extends into the housing is surrounded by one or more layers of insulating tape and by a tubular sheath which is shrunk onto the tape and exhibits at least some thermal-shock-absorbing characteristics.

Abstract: A sealable membrane is inserted within the filler plug receptacle of a high voltage bushing for providing access to the gas space above the dielectric oil used within the bushing. Gas sampling is achieved by inserting the needle of a hypodermic syringe through the membrane and withdrawing a quantity of gas to be sampled. The sealable properties of the membrane allow a plurality of samples to be taken without destroying the gas-tight seal.

Abstract: A pothead installation for a high voltage, high pressure oil-filled, electric cable in which the pothead is surrounded by a metal tank at ground potential, the tank being filled with sulfur hexafluoride gas under pressure. Oil and nitrogen within the pothead are conveyed to the exterior of the tank by a tube of insulating material having electrical characteristics and a length adequate to withstand at least the voltage difference between the cable conductor and the tank and having physical characteristics adequate to withstand at least the pressures of the oil and nitrogen. At the end of the tube at the tank wall, the tube is connected to a reservoir which is mounted exteriorly of the tank and which accumulates the oil and nitrogen. The reservoir has a venting valve for venting the nitrogen and oil, has a sight gauge for monitoring the oil level in the reservoir, and may have a float switch connected thereto for operating an alarm when the volume of the nitrogen exceeds a predetermined value.

Abstract: A conventional pothead-tank combination for an oil-filled electric cable is modified to replace the usual manually operable venting valve within the tank and on the pothead by a relief valve installed to close under pressure of the oil and is further modified to add a manually operable gate valve on the tank wall with the valve passageway aligned with the relief valve.

Abstract: A termination applicable to electric power cables for normal, high and very high voltages comprises a housing for accommodating an end length of the cable shield, or a shield section including the shield end and a cable length extending beyond said shield end and comprising the conductor and associated insulation. Provision is made within the housing for a conductive fluid body having completely immersed therein the shield section including the shield end, and an insulating fluid body fully or partially filling up the remaining space within the housing, the latter being suited to receive and contain said fluids with a good sealing effect.

Abstract: A high pressure, high voltage entrance bushing member using taper-sealing between an insulating plastic plug and a metal barrel. Spring loading, as by means of a spring lock washer, is used to urge the taper connections into precompression for proper high pressure fluid-tight seal. Dimensional changes due to temperature variations are accommodated by the taper connections. The high pressure bushing member is used in conjunction with a high temperature, high voltage bushing member, being connected by a conductor extending axially through a high pressure conduit containing a dielectric liquid. The overall entrance bushing assembly is employed in a system for electrically resolving emulsions. In such systems, the dielectric liquid is maintained at the same pressure as the emulsion being treated by means of a dynamic fluid barrier which prevents the intermingling of these liquids.

Abstract: An improved vapor-cooled terminal-bushing is provided for increased current-carrying capacity, such as 6,000 amperes, for example, in an oil-type circuit-breaker, being provided with a "dry" body portion, utilizing resinous materials, such as epoxy-resin formulations, for example.Preferably, the body portion of resinous materials, such as epoxy resin, for example, is composite, or of a two-piece construction, having an inner first epoxy-resin formulation having improved dielectric strength, and an outer-disposed externally-located "petticoat"-type insulating second body portion, having weather-sheds, the second weather-shed annular body portion being preferably cast directly onto the inner high-dielectric-strength first epoxy-body portion, and having some flexibility for adherence purposes.

Abstract: A fluid-filled electrical bushing for connecting an electrical conductor in a fluid-filled transformer to an electrical conductor in another enclosure. The electrical bushing includes a safety device consisting of two coaxial flexible capsules which are joined to a plate disposed therebetween and which respectively communicate with the dielectric fluid in the bushing and with the dielectric fluid in the transformer. The plate, which is movable in opposite axial directions in response to the pressure difference between the dielectric fluid in the bushing and the dielectric fluid in the transformer acting thereon, alternately engages first or second electrical contacts to complete an electrical circuit indicating an over-pressure condition caused by internal arcing, or the abnormal expansion or an insufficient amount of dielectric fluid within the bushing.

Abstract: An insulation housing has a central opening to allow the housing to be mounted on a high voltage conductor. A continuous, circular cylindrical electrode band is embedded within the housing and is capacitively coupled to a conductor which passes through the central opening of the housing. The electrode may be the sole electrical component encapsulated within the housing. The lead from the electrode is then coupled to indicators which are fixed on remotely positioned switchgear cubicles. The indicators include neon glow bulbs and a solid state relay which are operated by the energy derived from the capacitive pickup structure.