| 摘要 |
A molded case current limiting circuit breaker includes separable contacts, an operating mechanism releasable to effect automatic separation of the contacts, and a high speed electromagnetic trip device operable upon overcurrent conditions to release the operating mechanism and separate the contacts. The trip device includes a U-shaped pole piece disposed about a conducting path through the circuit breaker and a movable laminated armature mechanically coupled to the operating mechanism and magnetically coupled to the pole piece. The thickness of the armature is substantially greater than the thickness of the pole piece. During extreme overcurrent conditions electrodynamic force is produced upon the armature by magnetic flux in the pole piece. Upon saturation of the pole piece, force upon the armature continues to increase with increasing current due to electrodynamic force produced between the armature and the conducting path. |
