| 摘要 |
PROBLEM TO BE SOLVED: To suppress deterioration in insulation after current is cutoff, and improve reliability by providing a resin mold containing ceramic fiber having oxygen in a constitutive element on a part exposed an arc generated between a fixed contact and a movable contact. SOLUTION: When a heavy-current such as a short-circuit current flows, contacts 2,3 are dissociated to generate an arc 15 between them, and surrounding metal and resin are melted and discomposed to spray high temperature and pressure gas generated from them on each part in a direction of an arrow. At this time, glass fiber in a resin mold such as a plate 17 and an end plate 18 arranged in the vicinity of a space for the arc is decomposed by heat of the gas to generate atomic oxygen and SiO2, etc., and the atomic oxygen, carbon monoxide and carbon dioxide are similarly formed by the ceramic fiber in the resin molding. When insulation resistance is decreased, neither metallic particles nor free carbon may be generated, a circuit is cutoff because the insulative particles such as SiO2 are mixed in, and thereby insulation is improved.
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