| 摘要 |
In a dual-gas-blast puffer-type circuit-breaker a fixed insulating nozzle body (4) is integrated into a fixed insulating piston (10), forming thus a structural component. Said structural component is mounted on a fixed cylinder (11). Up to the large inner diameter of the latter the nozzle contour may expand freely, allowing thus a more effective removal of the arc plasma from the nozzle region. This feature facilitates interrupting the arc by increasing the cooling rate of the gas flow past the arc. The movable arc contact piece (17) is provided with a conical transition member between the nozzle shaped inlet side and the cylindrical base (16). That conical transition member is working like a movable piston exposed to the downstream gas flow pressure. Thus at least partly a selfcompensation of the increased gas pressure on the compression cylinder takes place in cases where large short circuit-currents are to be interrupted. This feature represents the precondition for a simple and thus reliable drive.
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