Abstract: A three-phase common tank type gas circuit breaker has a grounded tank filled with an insulating gas and accommodating three interrupter assemblies for three phases of the electric power. Each assembly includes a parallel electrical connection of an interrupter having stationary and movable contacts, a capacitor and a closing resistor. The interrupters for the three phases are disposed in spaced relationship circumferentially of the tank and have axes extending axially of the tank. The closing resistor for each phase is disposed on one side of the associated interrupter adjacent an adjacent interrupter for a different phase, while the capacitor for each phase is disposed on the inner or outer side of the associated interrupter, whereby the radial and axial dimensions of the grounded tank can be reduced.

Abstract: A three-phase combined type circuit breaker is disclosed which comprises a common housing, three-phase interrupting units in said common housing, movable contacts of the interrupting units connected through link mechanisms to operating devices for three phases respectively provided outside of the common housing, the switching operation thus being performed by phase. Rotary shafts are disposed in substantially the same plane in the link mechanisms. Each of the rotary shafts is provided with a connector for the movable contact, a connector for the operating device, and a sealing arrangement positioned between the two connectors for allowing the rotary shaft to rotate while holding the common housing in hermetic condition. This construction makes up a three-phase combined type circuit breaker capable of being operated by phase. The arrangement and construction of the three-phase rotary shafts simplifies maintenance and inspection of the interrupting units and the operating devices.

Abstract: A tank type gas circuit breaker comprises a sealed vessel which is filled with an insulating gas, insulating support means whose one end is fixed to the sealed vessel, a bracket which is fixed to the other end of the insulating support means, a linkage which is disposed in the bracket, and at least two interrupting units which are operated for opening and closure by means of the linkage and which are connected in electrical series with each other. At least two interrupting units which effect switching operations along axes being substantially parallel are disposed on at least one end face side of the bracket in a manner to be staggered in a direction of the axes, and one of the adjacent interrupting units located on the bracket side has its stationary contact member electrically connected with a movable contact member of the other interrupting unit at all times.

Abstract: A gas blast circuit breaker comprises one breaking assembly having a supporter and two breaking units at least movable contacts of which are supported on opposite ends of the supporter, and the other breaking assembly having a supporter and a single breaking unit at least a movable contact of which is supported on one end of the supporter. The two breaking assemblies are so arranged as to have only one breaking unit between the two supporters, whereby flows of blasting gas in the three breaking units of the two breaking assemblies can be prevented from interferring with each other.

Abstract: A puffer type gas circuit breaker comprising at least a pair of main movable and fixed contacts, a puffer device and a pair of preinsertion resistor contacts inserted in parallel with the main movable and fixed contacts, wherein the main movable resistor contact is mounted through a plurality of adjustment plates to a support arm mounted on the puffer device.

Abstract: Gas-insulated switchgear apparatus wherein a device providing a first disconnect gap and a second disconnect gap is located in a sheath filled with an insulating gas and kept at ground potential. The disconnect gaps providing device comprises a first movable contact and a second movable contact which are insulatedly supported by a support device with respect to the sheath. There is provided a device for individually actuating the movable contacts which device comprises a pair of insulated actuating rods disposed adjacent and extending parallel to the insulating support device.

Abstract: In a puffer type gas circuit breaker comprising at least a pair of main movable and fixed contacts, a puffer device and a pair of preinsertion resistor contacts inserted electrically in parallel with the main movable and fixed contacts, the preinsertion resistor contacts are closed prior to the closing of the main movable and fixed contacts, and are separated a short time after the main movable and fixed contacts have been closed.

Abstract: A circuit breaker operating apparatus comprising an operating piston connected to an operating member for operating a breaking section, holding means for mechanically maintaining the operation-complete state of the operating piston at the time of completion of its operation, spring means for giving a restitutive force to the operating member, and means for releasing an operating medium acting on the operating piston at the time of completion of its operation. The holding means includes a first lever connected to the operating piston and a second lever having an end connected to the first lever and the other end adapted to be locked by lock means. The lock means is so simple as to be arranged at an optimum position.