| 摘要 |
Provided is a circuit breaker capable of stable operation without change in tripping time before and after tripping, and without considerable modification to the conventional external shape and structure. A thermal tripping device (50) has a bimetal-upper base (52) secured to the distal end of a bimetal (51), a bimetal upper (54) rotatably provided to the bimetal-upper base and secured to a member (57) for adjusting overcurrent characteristics that faces a trip bar (22) via a predetermined gap, and a bimetal-upper spring (56) held to the bimetal-upper base and used for constantly urging the bimetal upper with a load that is equal to or greater than tripping load of an on-off mechanism (20), wherein the bimetal upper is rotated against the bimetal-upper spring by the curvature of the bimetal during overcurrent in the electric circuit, and the trip bar is driven via the member for adjusting the overcurrent characteristics. |
