| 摘要 |
PURPOSE:To simplify the circut constitution, by controlling a chopper circuit by an oscillator whose driving power source is a voltage to be detected, when the voltage to be detected which is converted into the pulse signal is transmitted by a pulse transformer. CONSTITUTION:A current is supplied to an armature 4 through a thyrister 2. The armature voltage (a) is detected by the insulation type voltage detecting circuit 7. A thyristor 5 is controlled by the signal therefrom and a field system 6 is controlled. Thus a DC shunt motor is driven. The insulation type voltage detector 7 is formed in the following way. The pulse signal is obtained by controlling the chopper circuit 21 by the oscillator 26 whose driving source is a constant voltage of the armature voltage (a). The output (b) is obtained through the pulse transformer and a rectifier 24. Therefore, a separate power source for driving the oscillator 26 is not required, the number of the pulse transformers can be reduced, and the circuit can be simplified. |
