| 摘要 |
Without great modification of the conventional outer shape and structure, a circuit breaker is provided which can realize stable operation without change in tripping time between before and after breaking. A thermal tripping device 50 includes: a bimetal upper base 52 fixed on a head end of a bimetal 51; a bimetal upper 54 rotatably provided on the bimetal upper base and fixed to an overcurrent characteristic adjustment member 57 opposing to a trip bar 22 via a predetermined gap; and a bimetal upper spring 56 held by the bimetal upper base and constantly energizing the bimetal upper by load equal to or greater than tripping load of an open/close mechanism portion 20. When overcurrent flows on an electric path, the bimetal upper is rotated against the bimetal upper spring by bending of the bimetal, and thereby the trip bar is driven via the overcurrent characteristic adjustment member. |
