Gas circuit breaker

Abstract

To enable prevention of the occurrence of a ground fault by suppressing carbonization of insulation material due to thermal gas flow, and consequently to enable deterioration of a cutoff performance to be suppressed.SOLUTION: A gas circuit breaker (1) comprises: an insulation operation rod (59) which is inserted into a hollow portion (601) of an insulation support (6), and in which a distal end portion can be projected into a hollow portion (512) of a movable side support (51); and a movable exhaust pipe (56) which is inserted into the hollow portion of the movable side support, and in which the distal end portion of the insulation operation rod is coupled to a lower end portion, a movable arc contactor (57) is provided in an upper end portion. In the movable exhaust pipe, a thermal gas flow generated in accordance with spray of arc suppression gas to an arc discharge enters into the inside from the upper end portion side, and is exhausted to the hollow portion oof the movable side support from the lower end portion side. A flange-shaped portion (11) is provided in a coupling portion of the insulation operation rod and the movable exhaust pipe. The flange-shaped portion includes a lower taper surface (13) which functions as a pressure rise suppression portion, and suppresses a pressure increase of a lower side space from exhaust power (511) in the hollow portion of the movable side support by an open-circuit operation.SELECTED DRAWING: Figure 7

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