| 摘要 |
<p>PURPOSE:To decrease a pulsating torque at starting by a method wherein a discharge circuit is connected to a discharge resistor in parallel, and a current is carried to the discharge circuit only when an AC voltage induced on a field coil at starting is impressed in reverse polarity to a diode of a rectifier. CONSTITUTION:A discharge circuit consisting of a series circuit of a thyristor 8 and a resistance 9 is connected to a discharge resistance 6 in parallel, and a gate circuit 7 to give a firing signal to a gate of the thyrsitor 8 when an AC voltage induced on a filed coil 2 becomes reverse in polarity to the diodes of rectifier 5. Therefore, since a current flows through the rectifier 5 when the AC voltage induced on the filed coil 2 at starting is normal in polarity to the diodes of the rectifier 5 but throughthe discharge circuit when reverse in polarity, a difference in current to flow is minimized, and thus a pulsating torque can be decreased at starting.</p> |
