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.

An insulating molded body to be used for an arc extinguishing device of a gas circuit breaker is provided. The insulating molded body includes a fluororesin mixture which contains a fluororesin and an oxygen generator configured to generate oxygen through thermal decomposition at 450° C. or more and 1,150° C. or less with an arc generated when a conduction current is interrupted. The oxygen generator is dispersed in the fluororesin. Also provided is a gas circuit breaker including an insulating nozzle formed of the insulating molded body.

A gas circuit breaker includes a first arc contactor electrically connected to a first lead-out conductor, a cylindrical guide portion provided on a second lead-out conductor side, a trigger electrode arranged to be movable between the first arc contactor and the guide portion, and igniting an arc along with a movement in a first half of a current breaking action, a compression chamber being formed by a cylinder having an outer wall and an inner wall both formed in a cylindrical shape, and a piston sliding between the outer wall and the inner wall, and an insulation nozzle guiding the arc-extinguishing gas to an arc ignited at the first arc contactor. The insulation nozzle is formed integrally with the inner wall of the cylinder.

A gas circuit breaker to reduce deterioration of insulation and current-breaking performance thereof includes a sealed container (8) filled with arc-extinguishing gas. A first fixed contactor portion (2) and a second fixed contactor portion (4) are fixed to the sealed container (8). A movable contactor portion (3) moves between the first fixed contactor portion (2) and the second fixed contactor portion (4) and conducts and breaks current between the first fixed contactor portion (2) and the second fixed contactor portion (4). An arc is generated between a fixed arc contactor (21) provided to the first fixed contactor portion (2) and a movable arc contactor (31) provided to the movable contactor portion (3) when current breaking action is extinguished by an arc-extinguishing gas being sprayed thereto. Unnecessary gas generated from the arc-extinguishing gas sprayed to the arc is accumulated in a gas chamber (5).

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.

There is provided a gas circuit breaker that can reduce deformation of an insulation nozzle and leakage of arc-extinguishing gas compressed to be sprayed to an arc, and can more surely maintain electric insulation performance. A gas circuit breaker 1 includes a trigger electrode 31 which is arranged to be movable between a first arc contactor 21 and a second arc contactor 41, which ignites an arc generated between the first arc contactor 21 and the trigger electrode along with a movement in a first half of a current breaking action, and which ignites the arc on the second arc contactor 41 along with the movement in a latter half of the current breaking action, a compression chamber 36 for pressurizing arc-extinguishing gas, the compression chamber 36 being formed by a cylinder 42 which has an outer wall 51 and an inner wall 52, each being formed in a cylindrical shape, and which is provided to the second arc contactor 41, and a piston 33 that slides between the outer wall 51 and the inner wall 52 in conjunction with the trigger electrode 31, and an insulation nozzle 23 that guides the arc-extinguishing gas pressurized in the compression chamber 36 to an arc ignited between the first arc contactor 21 and the second arc contactor 41. The insulation nozzle 23 is supported by the inner wall 52 of the cylinder 42.

A gas circuit breaker 1 includes an insulation nozzle 23 that guides arc-extinguishing gas to an arc between a first arc contactor 21 and a second arc contactor 41 when a trigger electrode 31 becomes an opened state relative to the first arc contactor 21. The second arc contactor 41 has an opening 41a for spraying the arc-extinguishing gas, and the opening 41a is closed by the trigger electrode 31 in the first half of a current breaking action, and is opened by separation of the trigger electrode in the latter half of the current breaking action. An opening area of a first exhaust port 41b formed between the second arc contactor 41 and the insulation nozzle 23 for exhausting the arc-extinguishing gas is 0.2 times or more and two times or less of an opening area of the opening 41a of the second arc contactor 41.

An electric current switch comprising: a housing; a contact lever including a proximal end and a distal end and is rotatable at a pivot point at the distal end, the contact lever including a lever arcing contact area and a lever arcing contact at the proximal end; a fixed contact assembly configured to receive the contact lever in a closed position of the contact lever, the fixed contact assembly including fixed main contacts and a fixed arcing contact, the fixed contact assembly being fixed relative the housing accommodating the fixed contact; the contact lever is configured to rotate about the pivot point between the closed position and an open position, the electric current switch further including a nozzle fixedly arranged to surround the position of the fixed arcing contact, the nozzle including at least one outlet to provide a flow of cooling gas towards the fixed arcing contact, the flow of cooling gas being in the proximal direction of the contact lever as when the contact lever in the closed position.

The present application concerns a high-voltage circuit breaker filled with insulating gas having a main axis A, including arcing contacts and an insulating nozzle, wherein an insulating gas flowing from a storage chamber and heated by an electric arc between the two arcing contacts is partitioned into a first gas flow and a second gas flow conducted outside of the insulating nozzle from opposite directions toward a main gas chamber, wherein the first gas flow flows through a first intermediary gas chamber and the second gas flow flows through a second intermediary gas chamber and is partitioned in a first portion directed to the main gas chamber and a second portion directed to an exhaust gas chamber, characterized in that the first portion of the second gas flow is smaller than the second portion of the second gas flow.

The invention relates to an electric arc-blast nozzle (5) for a circuit breaker comprising a middle portion (7) forming a throat defining internally an axial passage (13) for interrupting an electric arc, and two end portions (9, 11) extending on either side of the middle portion (7) and being designed to receive respective arcing contacts (1) and (3) that are movable axially relative to each other. The middle portion (7) and the two end portions (9, 11) are made of a same dielectric material obtained from a composition comprising a fluorocarbon polymer matrix, at least one inorganic filler and micro-capsules of liquid heptafluoro-iso-butyronitrile. The invention also relates to a circuit breaker including such a nozzle (5).