| 摘要 |
PURPOSE:To prevent mechanical, electrical noises by controlling to obtain an armature current value corresponding to a load by a chopper. CONSTITUTION:Power supply is stopped to phases A, B from DC power sources 2a, 2b only during zones in which the current of an armature 16 is lowered to a predetermined value form when it exceeds a set value by detecting the current of the armature 16, and the current of the armature 16 is conducted via capacitors 3a, 3b connected in parallel with the power source during stoppage. Accordingly, if the voltage applied to a motor exceeds a set value, the current of the armature 16 is held at a predetermined value corresponding to a load irrespective of the applied voltage. Therefore, the peak value of the AC voltage is set to twice or more of the voltage obtained for the set value to set the amplitude of the voltage contributing to the conduction of the current of the armature 16 to approx. 2/3 of the whole amplitude of a half cycle. Thus, the conducting width of the supplied AC side is widened, thereby preventing mechanical/electrical noises. |
