| 摘要 |
PURPOSE: To make a reliable transition from a start mode to a position detecting operation mode of a more in a shortest time by positioning the rotor of the motor at a predetermined position and then calculating the conduction timing of the armature winding sequentially every time the rotor position is detected. CONSTITUTION: A control circuit 10 positions the rotor 2a of a brushless motor 2 such that the rotor 2a and the stator 2b are locked. In the case of a three- phase four pole brushless motor 2, the rotor 2a is locked by switching the conduction twice regardless of the position thereof. Upon finishing the positioning, the control circuit 10 switches conduction of the armature winding to bring about a predetermined field state of the stator 2b. When the motor current is fed from the armature winding W side to the armature winding V side under that state, phase of the stator 2b advances by 60 deg.. |
