| 摘要 |
PURPOSE:To reduce the dispersion of the position of stoppage of a rotor by connecting a sub-switch in parallel with a main switching element in an adjacent phase through a resistor. CONSTITUTION:A phase control circuit 15 controls transistors Q1-Q4 according to a specified excitation system in response to stepping pulses. Resistors 16a, 16b for flowing currents generating bias magnetic flux are connected respectively between the lower end of a first phase winding A and the lower end of a second phase winding B and between the lower end of a third phase winding C and the lower end of a fourth phase winding D. When a rotor 12 is stopped, the rotor is stopped at an angular position slightly biassed to the right side from a center line 17 tying the central axis 12a of the rotor 12 and the center of the pole 8a of the rotor 12. Accordingly, the accurate angular position of stoppage can be obtained. |
