| 摘要 |
A bus-mountable, circuit-interrupting device, including an interrupting unit and a novel line-potential, manually-resettable operating mechanism for the unit, is usable in circuits in which faults may exceed the interrupting capability of the unit. A normally engaged pair of contacts in the unit is separable within an arc-extinguishing medium. The operating mechanism includes a robust, stored-energy operator, for separating the contacts, and a tripping mechanism, which selectively releases the stored operating energy. The tripping mechanism normally prevents release of the stored operating energy, and includes a high mechanical advantage lever-link system which permits a low latching force to counteract the stored operating energy. A ratchet-solenoid combination in the tripping mechanism selectively removes the low latching force. If a circuit fault occurs, the solenoid moves an arm past, and moves, the ratchet in a first direction, which does not remove the low latching force, but rather stores energy capable of moving the arm in a second direction. Arm movement in the second direction, which occurs immediately in the case of a fault within the interrupting capability of the interrupting unit, moves the ratchet so as to remove the low latching force, permitting the stored operating energy to overcome the latch and move the lever-link system, thereby separating the contacts. If the fault exceeds the interrupting capability of the unit, the arm moves in the first direction, but is prevented from moving in the second direction until the circuit is otherwise opened, as by an upstream protective device.
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