| 摘要 |
PURPOSE:To control the speed of a fan motor by detecting the operation of a handle switch by a diode connected in antiparallel, applying the detection signal to an integrator, comparing it with positive and negative reference voltages, and storing it in a memory. CONSTITUTION:The operation of a handle switch 11 is detected by a current direction detector 12, the detection signal is applied to an integrator 13, compared by comparators 14, 16 with positive and negative reference voltages 14, 17, stored in a memory 8, the output is compared with the output of a sawtooth wave generator 19, a pulse is outputted at the coincidence time point, a bidirectional thyristor 23 is controlled, and a fan motor 9 is controlled at the speed. The switches 11, 12 are formed of diodes 28, 29 and handle switches S1, S2 connected in antiparallel, the direction of the current due to the selection of the switches S1, S2 is detected and a signal is applied to the integrator 13. Therefore, only two conductors are provided between the body and the handle switch to control it. |
