| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve the structure of a slit arc-extinguishing plate such that excessive internal pressure rise of a breaker case is suppressed by reducing the amount of pyrolysis gas generated from the slit arc-extinguishing plate at current interruption, while ensuring high breaking performance by effectively exerting slit effect throughout the opening movement path of a moving contact. <P>SOLUTION: This circuit breaker is structured such that a pair of the slit arc-extinguishing plates 9 formed of an insulation material are arranged along an opening movement path of a moving contact 3 forming a pair with a fixed contact 2 by interposing the movement path and facing them to both its sides; and a slit arc-extinguishing space is formed between facing wall surfaces thereof. In the slit arc-extinguishing plate 9, cut-out parts 9a are formed such that the tip of the contact projects to the outside of a slit space at the opening position of the moving contact; step parts 9b in the plate thickness direction are formed at intermediate parts of the inside surfaces thereof; the slit distance d1 in the anterior region of the opening movement path and the slit distance d2 (d1>d2) of the posterior region thereof are set smaller and greater across the step parts, respectively. <P>COPYRIGHT: (C)2008,JPO&INPIT |
