| 摘要 |
PROBLEM TO BE SOLVED: To provide a circuit breaker whose short circuit breakdown performance is improved by rapidly exhausting an arc gas generated at arc-extinguishing action, while the size of the circuit breaker is maintained compact. SOLUTION: The circuit breaker comprises: a case 110; an opening and closing unit 130 that opens and closes the circuit by the connection or separation of the fixed contact 138 with the movable contact 137; an arc grid 142 placed stacking a plurality thereof adjoining to the fixed and movable contacts; a first arc barrier 152 placed adjoining to the arc grid, and provided with a first exhaust hole 151 in the top part of the case for exhausting arc gas; a second arc barrier 160 disposed in an opening formed in the bottom part of the case adjoining to the fixed and movable contacts, and provided with a second exhaust hole 161 for exhausting the arc gas; and a door 170 for preventing entering dust into the case through the second exhaust hole by opening the second exhaust hole only when the arc is generated. COPYRIGHT: (C)2005,JPO&NCIPI
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