Abstract: A combined pressure relief and pressure indicating mechanism includes a diaphragm closing a vent in a housing. The diaphragm is punctured if an excessive overpressure occurs in the housing to relieve same. A movable indicator is held from moving by the diaphragm as long as the housing pressure exceeds a minimum value. If the housing pressure falls below this value the indicator moves, its movement giving a visual indication of an underpressure.

Abstract: A shunt trip mechanism includes a ratchet facility added to a self-contained, line potential stored-energy operating mechanism of a circuit interrupting device. Operation of the ratchet facility releases the stored energy to operate the device. A portion of the ratchet facility may also be operated to reset the device if it has previously been operated by either the shunt trip mechanism or the operating mechanism's current-responsive elements. The main portion of the shunt trip mechanism is at ground potential and is mechanically tied to and operates the ratchet facility by a movable insulated strut. The strut is moved by the shunt trip mechanism upon the occurrence of an event such as transformer overpressure. A ground level handle may be operated to reset the device whether it was operated by the operating mechanism or the shunt trip mechanism.

Abstract: A circuit interrupting device has a stationary contact. A movable contact is carried by a movable double-walled conductive tube which is telescoped and electrically continuous with a stationary tube. The tubes carry all of the current through the device. A piston carried by the stationary tube defines a piston-cylinder with the movable tube. When the movable tube moves to open the contacts, the piston-cylinder forces dielectric gas to and past the gap therebetween. In a two-gap version of the device the stationary tube is also double-walled and carries a second stationary contact. A piston carried by the movable tube defines a piston-cylinder with the stationary tube. When a second movable contact jointly moves with the first movable contact to open the contact pairs, both piston cylinders force dielectric gas to and past both gaps.

Abstract: Disclosed is novel high-voltage fuse which includes therein attached tubular members. A method of attaching one tubular member such as a hollow metallic conducting tube to another tubular member such as a hollow insulator tube of a high voltage fuse comprises the steps of inserting the metallic tube into the insulator tube to a desired location and then expanding the metallic tube radially outwardly at a position where engagement is desired until the metallic tube engages and at least partially fills an annular groove on the interior of the insulator tube. To further provide a moisture tight seal at the point of engagement, an elastomeric compound such as a room-temperature-vulcanizing silicone rubber may be placed in the groove to assure a moisture tight seal when the metallic tube is expanded. The exterior of the insulator tube is slightly deformed due to expansion of the metallic tube, and the quality of the connection between the tubes may be determined by the amount of this slight deformation.

Abstract: Disclosed is a family of polyphase outdoor interrupter switch arrangements suitable for service in power systems rated up to 34.5 kv with but a single interrupting switch unit per phase. Two insulators are mounted on a base member with one insulator supporting a switch blade hinge assembly and the other insulator supporting an electrical jaw contact and interrupting unit. A linkage arrangement mounted to the hinge assembly connects the movable blade to an insulating push rod. The two supporting insulators remain stationary when the switch operates, and only the insulating push rod moves to provide the motive force. The insulating push rod is connected to a lever mounted on a polygon-shaped (preferably hexagonally-shaped) shaft which is mounted for rotation on the base member. A drive lever and connecting linkage is also connected to the shaft.

Abstract: A method of attaching one tubular member such as a hollow metallic conducting tube to another tubular member such as a hollow insulator tube of a high voltage fuse comprises the steps of inserting the metallic tube into the insulator tube to a desired location and then expanding the metallic tube radially outwardly at a position where engagement is desired until the metallic tube engages and at least partially fills an annular groove on the interior of the insulator tube. To further provide a moisture tight seal at the point of engagement, an elastomeric compound such as a room-temperature-vulcanizing silicone rubber may be placed in the groove to assure a moisture tight seal when the metallic tube is expanded. The exterior of the insulator tube is slightly deformed due to expansion of the metallic tube, and the quality of the connection between the tubes may be determined by the amount of this slight deformation. Also disclosed is a novel fuse produced by this method.

Abstract: End ferrules of a current limiting fuse are mounted to the end of a relatively fragile non-metallic insulator housing of the fuse by magnetic pulse forming. The end ferrules are formed so that there is a flat circular end wall and an annular mounting flange. The flat circular end walls are of a first thickness sufficient to withstand mechanical forces that may be experienced due to fuse operation or due to mounting of the fuse. The annular mounting flange is of a second thickness less than the first thickness so that the flange can be compressed around the housing by magnetic pulse forming without causing undue stress to be exerted on the housing that may result in damage to the housing. A unique elastomer ring seal is provided between the housing and the end ferrule to assure a moisture tight seal.

Abstract: A breather assembly for permitting atmospheric venting to the interior of electrical apparatus such as a high voltage fuse while preventing moisture from entering the fuse comprises three separate chambers communicating in such a way that the atmosphere can be vented to the interior of the fuse but moisture is precluded from entering the interior of the fuse regardless of the orientation of the fuse body.