| 摘要 |
A motor drive assembly includes a stationary housing, a shaft rotatably carried by the housing for driving a load, a gear box rotatably carried by the shaft, and an electric motor in the gear box having a rotor coupled by a gear train to the shaft. A switch in the housing near the gear box is operated when the gear box rotates against a spring bias in response to the rotor's exerting an increased predetermined torque. The motor may have an auxiliary winding in circuit with the switch to reduce power consumed by the motor when the switch is operated. Alternatively, a solenoid may be connected to the switch to hold the rotor stationary when the motor stops. The motor may have a main drive winding which is de-energized by the switch.
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