Disclosed is a gas insulated circuit breaker having enhanced insulation properties. A gas insulated circuit breaker comprises: a fixed cylinder unit of which a movable contact point has an internal space; a movable piston unit which is slidably inserted into the inner space of the fixed cylinder unit; a fixing unit provided in a rear of the fixed cylinder unit in the internal space of the fixed cylinder unit; a puffer chamber which is formed by having the movable piston unit, fixed cylinder unit and fixing unit, surrounding the puffer chamber; and a gas inlet unit which forms a path, between the puffer chamber and the outer part of the fixed cylinder unit, through which a gas flows.

A gas exhaust diffuser for a circuit breaker, comprising a first casing extending longitudinally along a principal axis with an open end to allow gas to enter and a closed end, and a second casing coaxial to the first casing, extending along the principal axis, with at least one outlet to allow gas to escape, the closed end of the first casing being arranged in the second casing and the first casing having at least two radial openings near its closed end to provide a fluid communication between the first and second casing. A plurality of incurved elements are positioned radially in the second casing at the at least one radial opening to create a rotation of an entering exhaust flow in a plan perpendicular to the principal axis, thereby generating a substantially helicoidally-shaped exhaust flow path in the second casing.

The present disclosure relates to a wiring circuit breaker and, more specifically, to a wiring circuit breaker having an expanded arc gas discharging port formed through a lower part of an enclosure and thus having enhanced exhaust performance. A wiring circuit breaker according to an embodiment of the present disclosure comprises: an enclosure for the wiring circuit breaker; a base assembly coupled to the inside of the enclosure; an exhaust duct connected to an exhaust part of the base assembly; and a terminal part mount coupled to a terminal part of the enclosure and connected to the exhaust duct, wherein a center part exhaust groove is formed on the exhaust duct, and a center part exhaust hole communicating with the center part exhaust groove is formed through the terminal part mount.

An insulation rod cover is fitted to an end portion of a puffer shaft and the insulation rod cover is fitted to a circuit-breaker side coupling pin coupling between a puffer shaft and an insulation rod, thereby allowing the insulation rod cover to be held at a joint between the puffer shaft and the insulation rod. In a first half of a circuit-breaking operation, the insulation rod cover is positioned in the exhaust cylinder and the exhaust of the hot gas from the puffer shaft is suppressed to increase the pressure of an extinguishing gas to be sprayed onto the arc. In a last half of the circuit-breaking operation, the insulation rod cover is positioned in a guard cylinder to promote the exhaust of the hot gas from the puffer shaft as well as to suppress the flow of the hot gas into the insulation cylinder.

The present invention includes a wear-resistant material including: a base material formed of pure aluminum or an aluminum alloy having a finely asperity structure on a surface thereof; and a coat including a hydrated oxide coat of aluminum, the coat being formed on the surface of the base material. Further, the present invention including a puffer cylinder including: a finely asperity structure on an inner-wall surface thereof; and a coat including a hydrated oxide coat of aluminum, the coat being formed on the inner-wall surface of the puffer cylinder. The present invention also includes a puffer-type gas circuit breaker includes the above puffer cylinder.

The disclosed circuit-breaker for high-voltage applications includes at least one making and breaking unit having a first contact and a second contact for forming an electrically conductive connection, wherein at least one of the contacts is movable along an axially extending switching axis of the circuit-breaker between a closed position and an open position, and a first contact housing having a guiding passage surrounding and forming with the first contact a circumferential gap, which first contact housing has at least one recess surrounding the first contact, which at least one recess is open towards the first contact by means of a recess opening facing the first contact, wherein an extension of the recess opening along the switching axis is shorter than an extension of the at least one recess along the switching axis and/or two or more the recesses are arranged axially adjacent to one another.