| 摘要 |
An improved puffer-type gas-blast circuit-interrupter is provided having a movable operating cylinder assembly movable over a relatively-fixed piston structure. A high compression ratio is obtained during the opening operation by minimizing the "dead" volume of arc-quenching gas within the movable operating cylinder, and an efficient gas-flow path through the movable cylinder assembly smoothly converges through the movable nozzle throat-area into the drawn arc. A high electrical withstand capability is accomplished by using a generous radius on the lower ends of external stationary main contact fingers, and by shrouding, or shielding the stationary contact probe within the surrounding shield of the stationary contact fingers. The circuit-interrupter of the present invention is adapted for various current ratings, such as 2,000 amperes, 3,000 amperes, or 4,000 amperes, for example, by varying the number of stationary main contact fingers used surrounding the movable operating gas-cylinder. High-interrupting performance is obtained with a reduced residual gas volume at the end of the opening stroke, and, consequently, a higher gas-compression ratio is obtained. The gas-flow downstream of the nozzle throat area is confined within the cluster of stationary main contact fingers, and this cools the ejected gas to prevent voltage breakdown to electrical members at another potential. Open venting ports are provided at the upper end of the stationary contact finger cluster to prevent stagnation of the hot arced gas flowing into the stationary contact finger cluster, which thereby permits the hot arcing gases to be blown out of the way to insure good interrupting performance and a high breakdown value.
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