| 摘要 |
PURPOSE:To eliminate a position detector for directly detecting the position of the pole of a rotor by starting a brushless motor based on a synchronous rotation signal from oscillating means, a frequency signal and a phase detection signal from signal generating means, and steadily operating it. CONSTITUTION:A synchronous rotation signal is applied from oscillating means 20 to a commutation signal generator 21 at the time of starting, and a brushless motor is started as a synchronous motor through a driving circuit 22. Thereafter, a frequency signal from signal generating means 15 is applied to the generator 21, and the motor is continuously rotated as a synchronous motor through the circuit 22. Further, the generator 21 is reset each time a phase detection signal is applied to correct so that a commutation phase becomes a predetermined phase. Accordingly, thereafter, even if a load is varied, the motor is not stepped out, but stably rotated. A stable signal having no variation is obtained without influence of magnetic noise. |
