| 摘要 |
PURPOSE:To attenuate noise, by multiplying partial driving current flowing to a plurality of stator coils with the change-over of the current in order with a specified conduction angle, at the time of the change-over. CONSTITUTION:So far as the rotor 6 of a brushless motor is concerned, on the periphery of a laminated core, four main poles 2 and twelve auxiliary poles 7 as permanent magnets are formed independently, and the auxiliary poles 7 are formed by arranging poled N, S divided into three equally and alternately at positions confronted with the four respective main poles 2. On a stator core 8, stator coils 4r-4t are arranged, and main magnetism-sensitive elements H1-H3 for discriminating the poles N, S of the main poles 2 and generating the output of detection signal for a changeover conduction angle, and an auxiliary magnetism-sensitive element H4 for discriminating the poles N, S of the auxiliary poles 7 and generating the output of detection signal for a multiple conduction angle are arranged. Then, by multiplying the driving current of the stator coils 4r-4t partially according to said detection signal with a drive circuit 10 and by switching the current, the rotor 6 is rotated. |
