| 摘要 |
An elevator rescue system includes a power source of back-up electrical power. A manually-operated, rescue enable switch switchably permits the transmission of electrical power from the power source to a motor brake coil of an elevator car during a rescue operation such that the energized coil releases the motor brake to move the car to a desired landing. A speed detector measures the speed of the elevator car and thereupon generates a speed control signal corresponding to the speed of the car. An overspeed detection circuit has a first input for being actuated when receiving electrical power from the power source, a second input for receiving the speed control signal, and an output for transmitting electrical power to the motor brake coil when the speed control signal is below a predetermined value and for automatically stopping the transmission of electrical power when the speed control signal becomes higher than a predetermined value. A manually-operated brake release switch has an input and an output. The input is coupled to the output of the overspeed detection circuit, and the output is to be coupled to the motor brake coil of the elevator car for transmitting electrical power to release the motor brake when the brake release switch is closed.
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