| 摘要 |
A control system having a motor protection circuit is provided to protect a DC(Direct Current) motor and a circuit driving the motor from electrical short, over-current, and overheating by a motor protection circuit. A control system equipped with a motor protection circuit includes: a power source unit for supplying voltage-regulated electricity after receiving electricity supplied from a battery through a fuse when a vehicle engine is turned on; a key pad having input switches and lamps to operate an auxiliary step, a door switch for detecting opening and closing of a door; a sensor unit having sensors for detecting extension, withdrawal, and emergency stop of the auxiliary step and sending corresponding signals to a control unit; a speaker for emitting alarming sound during opening and closing of the auxiliary step; a display composed of red lamps and amber lamps for emitting visual warning signals during opening and closing of the auxiliary step; a control unit(90) for controlling the system by making electrical connection of interface circuits connected to the keypad, the door switch, the sensors, the speaker, and the display; a motor drive unit(70) having a decoder and a bridge circuit for driving a motor in a clockwise direction or a counter-clockwise direction upon receiving the control signal emitted from the control unit; and a motor protection circuit(100) for protecting the motor drive unit by an electrical-short protection circuit(110), an over-current protection circuit(120), and an overheating protection circuit(130).
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