| 摘要 |
PROBLEM TO BE SOLVED: To lessen possibilities of abnormal stoppage of a brushless motor due to a bad start-up and make it possible to surely shift to a position detecting operation mode by confirming that the motor has started up stably when starting up the motor using a position detecting operation and a synchronous operation. SOLUTION: A controlling circuit 11 supplies a predetermined voltage to a brushless motor 4 and starts it up, After it starts up the motor, it detects the position of a rotor based on output position detection signals of a position detecting circuit 10. Each time the position of the rotor is detected, the current conduction of armature windings U, V, W of the brushless motor 4 is switched. If the position cannot be detected within predetermined period of time, the current conduction of the armature windings is forcibly switched. When the conduction is switched at a given number of times and then an operation mode is shifted to a position detecting operation mode, the stability of rotation checked, based on the information (whether the position detection has been conducted, intervals of position detections, etc.) so far. When the rotation is judged unstable, the motor is restarted. When the rotation is judged stable, the operation mode is shifted to the position detecting operation mode. |
