Circuit breaker e.g. molded-case circuit breaker, has plates disposed along length of path of circuit to form space that is divided into regions, where spacing is increased to position of point and in opposite to point of one region

摘要

The breaker has narrow gauge arc extinction plates (9) made of isolating material and disposed along length of an opening movement path of a circuit of a movable contact (3) to form a narrow gauge arc extinction space that is divided into a region closer to a point of a fixed contact (2) and another region at an open circuit side. Narrow gauge spacing is adjusted to be narrower in the former region than another narrow gauge spacing in the latter region. Third narrow gauge spacing is increased to a position of a movable contact point (3a) and is opposite to the point (3a) of the latter region.