| 摘要 |
PURPOSE:To provide a drive current having desired accurate waveform in a brushless DC motor by encoding the drive signal waveform information to digital code, storing the digital code on the entire periphery of the rotor, and reading it by a detector to form a drive signal. CONSTITUTION:A magnetic coating layer 17 is formed on the entire side periphery of the outer periphery of a rotor yoke 3 of a brushless DC motor, magnetic tracks are formed to record drive current waveform information through a magnetic head at the layer 17 to store the information thereon. Multi-track heads 18, 19 are arranged at the position where their electric angles are different at 90 deg. each other as an element for reading the waveform information. The signals picked up by the heads 18, 19 are supplied through limiter amplifiers 20, 21, comparators 22, 23 and flip-flops 24, 25 to stator coils 4, 5. Accordingly, accurate waveform signal can be readily obtained to provide constant rotary torque regardless of the rotational angle position of the rotor. |
