| 摘要 |
PURPOSE:To eliminate erroneous function of a fault judging circuit and to achieve stable drive control by providing a voltage fluctuation detecting means, and means for modifying the input signal level of a rotation determining means upon detection of voltage fluctuation higher than a specific level. CONSTITUTION:A Hall element 4 for detecting the polarity inverting position of a field is arranged in a brushless motor 3 and connected with a switching control circuit 130, then the target rotation of the brushless motor 3 is set by means of a rotation setter 1. A voltage fluctuation detecting circuit 150 detects voltage fluctuation of a DC power source 2, and the rotation being set by the rotation setter 1 and fed to a rotation setting circuit 100 is lowered forcibly upon detection of voltage fluctuation higher than a predetermined level. By such arrangement, erroneous function of fault judging circuit 160 can be eliminated resulting in stable drive control. |
