A movable part of a circuit breaker for a gas-insulated switchgear is proposed. The movable part includes a puffer cylinder, a nozzle, and a main contact. An outer rib at the rear end of the nozzle is hooked to a hook rib at the front end of the hook part of the puffer cylinder. A chamber guide is provided inside the puffer cylinder so that the nozzle is immobilized. The main contact is mounted on the outer surface of the front end of the hook part. Thus, the number of components constituting the movable part of the circuit breaker is reduced, and the number of bolting points is reduced, thereby greatly reducing man-hours in an assembly work and preventing a main contact separation from occurring due to bolt loosening.

A gas circuit breaker of an embodiment includes a sealed container, a first contact part and a second contact part, an operation mechanism, an insulating nozzle, a pressure accumulator, and an electric field shield. The insulating nozzle is displaced in conjunction with the first contact part in a separation process of the first contact part and the second contact part. The insulating nozzle surrounds arc discharge generated between the first contact part and the second contact part. The electric field shield is attached to the insulating nozzle. The electric field shield has a floating potential during a period of at least part of the separation process. The electric field shield is electrically connected to the second contact part such that the electric field shield has the same potential in a completely open electrode state in which separation between the first contact part and the second contact part is terminated.

A movable part of a circuit breaker for a gas-insulated switchgear is proposed. The movable part includes a puffer cylinder, a nozzle, a main contact, etc. An outer rib at the rear end of the nozzle is hooked to a hook rib at the front end of the hook part of the puffer cylinder. A chamber guide is provided inside the puffer cylinder so that the nozzle is immobilized. The main contact is mounted on the outer surface of the front end of the hook part. In the present invention, the number of components constituting the movable part of the circuit breaker is reduced, and the number of bolting points is reduced, thereby greatly reducing man-hours in an assembly work and preventing a main contact separation from occurring due to bolt loosening.

A gas circuit breaker of an embodiment includes a sealed container, a first contact part and a second contact part, an operation mechanism, an insulating nozzle, a pressure accumulator, and an electric field shield. The insulating nozzle is displaced in conjunction with the first contact part in a separation process of the first contact part and the second contact part. The insulating nozzle surrounds arc discharge generated between the first contact part and the second contact part. The electric field shield is attached to the insulating nozzle. The electric field shield has a floating potential during a period of at least part of the separation process. The electric field shield is electrically connected to the second contact part such that the electric field shield has the same potential in a completely open electrode state in which separation between the first contact part and the second contact part is terminated.

A switching arrangement includes an interrupter unit with a first and a second switching contact piece. A switching path can be formed between the two switching contact pieces under a relative movement of the same. At least one of the switching contact pieces is arranged within a hollow body. The switching contact piece is supported by a transversal crosspiece that crosses the hollow body. The transversal crosspiece is braced at opposite sections of the hollow body.

A gas circuit breaker is configured by comprising a tank filled with arc extinguishing gas, a pair of fixed side arc contact and moving side arc contact in the tank, a puffer chamber formed with a puffer cylinder including the moving side arc contact at its end and a fixed piston, and an insulating nozzle, attached to the end of the puffer cylinder, surrounding the moving side arc contact, that forms a flow channel to guide arc extinguishing gas from the puffer chamber to the contacts. A puffer cylinder 104 has a cylindrical member 104a at a breaker side end, an end of the insulating nozzle 101 is provided in the cylindrical member 104a. And the gas circuit breaker is configured by further comprising a hollow moving side main contact 102 at a breaker side end of the cylindrical member 104a, a pressing metal fitting 103 to engage an insulating nozzle 101 in the hollow part of the moving side main contact 102.