| 摘要 |
An undervoltage release device for a circuit breaker is disclosed having an operating mechanism, a trip bar, line and load terminals, and a cover. The device includes a housing, a solenoid, upper and lower actuators aligned with a plunger of the solenoid and in selective contact with the trip bar, plunger and actuator reset levers mounted upon the solenoid frame, and pair of terminals in electrical contact with the solenoid coil and line terminals of the breaker, wherein the force of the solenoid corresponds to the line voltage. Also disclosed is a method for tripping a circuit breaker when line voltage drops below a selected value, in a circuit breaker having an operating mechanism and a trip unit with an intermediate latch. The method includes steps of closing the circuit breaker with the operating mechanism, installing the device in a cover of the circuit breaker, the device having a solenoid with a plunger and a plurality of actuators in selective contact with the plunger and the trip unit; and wiring the solenoid in parallel with the load circuit, wherein the magnetic force of the solenoid is proportional to the line voltage and maintains the plunger in contact with the actuators, and wherein the plunger is released by the solenoid when the line voltage drops below the selected value, thereby providing for at least one actuator to contact the trip unit and open the circuit breaker.
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