The invention concerns a double-motion circuit breaker comprising primary and secondary movable contacts slidingly mounted within primary and secondary holders, wherein the primary movable contact comprises a tulip and a contact cylinder attached thereto, and the secondary movable contact comprises a pin for engaging the tulip but no counter-contact for engaging the contact cylinder. The circuit breaker also has a non-linear linkage mechanism with a pin and slot mechanism, and a fixed dielectric shield provided on the secondary holder. During disconnection, the linkage mechanism is preferably arranged to move the pin more than the tulip, proportionally to their maximum stroke, so as to quickly bring the pin tip within the fixed dielectric shield, whereafter the tulip moves more than the pin. This circuit breaker is cheaper, lighter and can be disconnected more quickly.

The present disclosure relates to an arc extinguishing assembly, including side members which are spaced apart by a certain distance and disposed to face each other; an exhaust which is installed at an upper part of the side member; a plurality of grids which are installed between the side members and having both ends fixed to each of the side members; and an arc guide whose one side is coupled to the side member and which is installed at a lower part of the plurality of grids, wherein the arc guide is made of a material having heat resistance, and a circuit breaker including the same.

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 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.

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 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.

A nozzle with an electric arc-blast having a median part of a first dielectric material and two end parts. The nozzle includes an insert of a second dielectric material, chosen from among: a composite material including a fluorocarbon polymer matrix and inorganic filler A chosen from among a sulfur, a ceramic and an oxide (SiO2, TiO2, Al2CoO4, ZnO, BaTiO3 and P2O5), in a percentage weight ranging between 0.1% and 10%, and/or at least one inorganic filler B (a graphite, a mica, a glass and a fluoride), in a percentage weight ranging between 5% and 50%, and a ceramic material including compound(s) (a carbide, a boride and an oxide).

According to an embodiment, a gas-blast circuit breaker comprises a heat removal unit in a flow path of arc extinguishing gas. The heat removal unit each includes: plate-shaped heat removal members contacting the arc extinguishing gas flowing in the flow path; and a holding portion holding the plate-shaped heat removal members to stack the heat removal members at intervals in a thickness direction. Each of the heat removal members includes: an upstream side end portion; a downstream side end portion; and a thickest portion with a largest thickness which is provided between the upstream side end portion and the downstream side end portion. Thickness of the heat removal member continuously changes between the upstream side end portion and the downstream side end portion via the thickest portion.

According to an embodiment, a gas-blast circuit breaker comprises a heat removal unit in a flow path of arc extinguishing gas. The heat removal unit each includes: plate-shaped heat removal members contacting the arc extinguishing gas flowing in the flow path; and a holding portion holding the plate-shaped heat removal members to stack the heat removal members at intervals in a thickness direction. Each of the heat removal members includes: an upstream side end portion; a downstream side end portion; and a thickest portion with a largest thickness which is provided between the upstream side end portion and the downstream side end portion. Thickness of the heat removal member continuously changes between the upstream side end portion and the downstream side end portion via the thickest portion.

A nozzle with an electric arc-blast having a median part of a first dielectric material and two end parts. The nozzle includes an insert of a second dielectric material, chosen from among: a composite material including a fluorocarbon polymer matrix and inorganic filler A chosen from among a sulfur, a ceramic and an oxide (SiO2, TiO2, Al2CoO4, ZnO, BaTiO3 and P2O5), in a percentage weight ranging between 0.1% and 10%, and/or at least one inorganic filler B (a graphite, a mica, a glass and a fluoride), in a percentage weight ranging between 5% and 50%, and a ceramic material including compound(s) (a carbide, a boride and an oxide).