| 摘要 |
PURPOSE:To stably operate a motor at switching time by switching the operation in the prescribed phase relation with small phase difference between output signals of rotating magnetic field generating means at normal operation time from the start. CONSTITUTION:A brushless motor 3 having a magnet rotor 5 is rotated by the energization and the interruption of an armature winding 4 by semiconductor switching group 2. After started by starting command means 12, a period signal of the prescribed frequency is input from generating means 8 to rotating magnetic field generating means 9 to form 3-phase synchronizing signals 9-U-W phases displaced at 120 deg., and the group 2 is controlled through the means 11, the means 12. Further, the drive power source 1 of the motor 3 is increased within low voltage to forcibly rotate a magnet rotor 5. Thus, after the prescribed time is elapsed, switching means 11 is switched by a switch command by the means 10, the position detection signal of the rotor 5 is output from comparator group 7 to the means 12 to normally rotate the motor 3. |
