| 摘要 |
The lock up detection circuit is organized with a bridge rectifier(B) rectifying AC voltage, the switching transistor(IU,ID) (transistor(TRU1-TRU3) and transistor(TRD1-TRD3)), and a brushless DC motor(M). When the power is supplied to the input terminal(AC), each transistor(TRU, TRD) starts to drive sequentially according to the drive signal. Then the rectified voltage is applied to the motor to initiate washing. While washing, the hole sensor(4) on the motor senses the rotation drive pulse of the motor. It is sent to the base terminal of the transistor(Q1-Q3) of the switching unit(5) to output a waveform to the microcomputer(2) that compares the waveform of the input drive pulse with a setting to show whether the motor runs properly or not on the display(3) in order to prevent the motor from being damaged by lock up or overload.
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