| 摘要 |
The invention relates to a circuit breaker including a trip bar assembly (60) which is movable to a circuit-breaker tripping position by a bimetallic element (38) deflecting in response to an overload current, and by a magnetic armature (66) magnetically attracted (yoke 100) in response to a fault or short-circuit current. …<??>The armature (66) is connected to the trip bar assembly (60) in such a manner (flexible attachment member 68, and rigid, preferably metallic, backing member 67) as to cause the trip bar assembly to move positively as one with the armature during movement thereof due to magnetic attraction, and to enable the trip bar assembly (by virtue of the flexible armature attachment 68) to be moved beyond its normal tripping position when the armature is in its fully attracted position. …<??>Enabling the trip bar assembly to move beyond its tripping position enables it to yield to the bimetallic element (38) in the event of a wide deflection thereof resulting from high thermal loading. Thus, the bimetallic element can deflect essentially unrestrainedly and, hence, without risk of taking a set and falling out of calibration. Accommodating wide bimetallic deflections in this manner permits the use of small-gap magnetic trip means for fast response. |
