A gas-insulated low- or medium-voltage load break switch includes: a housing defining a housing volume for holding an insulation gas at an ambient pressure; a first arcing contact and a second arcing contact arranged within the housing volume, the first and second arcing contacts being movable in relation to each other along an axis of the load break switch and defining a quenching region in which an arc is formed during a current breaking operation; a pressurizing system having a pressurizing chamber arranged within the housing volume for pressurizing a quenching gas from an ambient pressure p.sub.0 to a quenching pressure p.sub.quench during the current breaking operation; and a nozzle system arranged within the housing volume for blowing the pressurized quenching gas in a subsonic flow pattern from the pressurization chamber onto the arc formed in the quenching region during the current breaking operation. The nozzle system includes at least one nozzle arranged for blowing the quenching gas from an off-axis position predominantly radially inwardly onto the quenching region.

A movable main contact; a movable arc contact; a puffer cylinder including the movable main contact; a hollow rod that is arranged inside the puffer cylinder, includes the movable arc contact, and has an inner space through which an insulating gas flows; a thermal puffer chamber surrounded by the puffer cylinder and the hollow rod; an insulating cover that is provided to the hollow rod, and covers the movable arc contact; an insulating nozzle provided to the puffer cylinder; and a cylindrical flow guide extending in the axial direction are included. The flow guide is installed in the thermal puffer chamber, positioned on the outer circumference side of the hollow rod, and connected to the insulating nozzle. The space between the flow guide and the hollow rod is connected to the space between the insulating nozzle and the insulating cover, and serves as a flow path of the insulating gas.

There is provided a gas circuit breaker that can suppress the mechanical vibration during movement of the moving electrode, reduce the generation of a triple junction during operation of the gas circuit breaker and the generation of the metal foreign materials, and maintain the electrical insulation performance more reliably. A first arc contactor 21, a cylindrical second arc contactor 31, a bar-shaped trigger electrode 31 arranged to be movable between a first arc contactor 21 and a second arc contactor 41, and moving in the cylindrical second arc contactor 41 during the latter half of the current breaking action to ignite the arc to the second arc contactor 41, and a guide portion 41b having an inner diameter larger than an outer diameter of the trigger electrode 31, and the inner diameter smaller than an inner diameter of a portion of the second arc contactor which is close to the trigger electrode 31, and arranged in a cylinder of the second arc contactor 41 so as to circulate around the trigger electrode 31 when the trigger electrode 31 is in the closed state with the first arc contactor 21, are included.

The present disclosure provides a gas-insulated high or medium voltage circuit breaker including a first arcing contact and a second arcing contact, wherein at least one of the two arcing contacts is axially movable including a first and a second state of motion along a switching axis, wherein during a breaking operation, an arc between the first arcing contact and the second arcing contact is formed in an arcing region; a nozzle including a channel directed to the arcing region, for blowing an arc-extinguishing gas to the arcing region during the breaking operation; a diffuser adjacent to the nozzle, for transporting the gas from the arcing region to a region downstream of the diffuser; a buffer volume directly downstream of the diffuser, and an enclosure substantially surrounding the buffer volume circumferentially.

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.

The present disclosure provides a gas-insulated high or medium voltage circuit breaker including a first arcing contact and a second arcing contact, wherein at least one of the two arcing contacts is axially movable including a first and a second state of motion along a switching axis, wherein during a breaking operation, an arc between the first arcing contact and the second arcing contact is formed in an arcing region; a nozzle including a channel directed to the arcing region, for blowing an arc-extinguishing gas to the arcing region during the breaking operation; a diffuser adjacent to the nozzle, for transporting the gas from the arcing region to a region downstream of the diffuser; a buffer volume directly downstream of the diffuser, and an enclosure substantially surrounding the buffer volume circumferentially.

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 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.

An electrical switching device includes a first switching contact piece and a second switching contact piece. The switching contact pieces can be displaced in relation to each other. The first switching contact piece is surrounded by a fluid flow guiding device. An enveloping contour of a flow duct, disposed between the fluid flow guiding device and the first switching contact piece, is greater at its end facing the second switching contact piece than an enveloping contour of the first switching contact piece at its end facing the second switching contact piece.

An object is to enhance direct-current insulating performance of a gas-blast circuit breaker. The gas-blast circuit breaker includes: a pair of main contacts disposed in a gas tank to face each other and configured to operate for opening and closing a circuit; a pair of arc contacts disposed to face each other and configured to operate for opening and closing the circuit, the arc contacts being disposed coaxially with the main contacts at locations close to the centers of the main contacts, respectively; and an elastic electrically conductive material disposed on an outer surface of an insulating nozzle facing an inner surface of one of the main contacts.