| 摘要 |
PROBLEM TO BE SOLVED: To charge a capacitor by providing a capacitor to accumulate charges enough to maintain the ON condition of a power switching element for the predetermined period between a switching element to give a DC power and a power switching element to output a voltage waveform to a stator winding. SOLUTION: In a power supply circuit 10 for a signal, a photo-coupler 11 shifts voltage level of DC 12 V and DC 140 V between a signal generating circuit 8 and an inverter circuit, and connects the collector terminal of the transistor of a photo-coupler 14 to the DC power supply of DC 12 V via a diode 12 and a resistor 13. A capacitor 15 is connected between the collector terminal of the transistor of a photo-coupler 11 and the source terminal S of FET 2 to connect in parallel a resistor 16 to the capacitor 15. The resistor 16 discharges gradually the capacitor 15 when the motor 1 stops. As a result, the capacitor can be charged not depending on the stop condition of the rotor at the time of starting rotation. |
