Patent ID: 7110206

Claim:
A motor comprising: a rotor, plural-phase windings, a DC voltage source, a plurality of first power transistors and a plurality of second power transistors forming current paths from said DC voltage source to said plural-phase windings, position detecting means producing a position signal in response to a rotation of said rotor, and activation operation means controlling activation of said first power transistors and said second power transistors, said activation operation means includes: starting operation means for starting activation of said plurality of first power transistors and said plurality of second power transistors in response to a start signal; and rotation control means for controlling activation of said plurality of first power transistors and said plurality of second power transistors in response to said position signal after the operation of said starting operation means, said starting operation means comprises: phase changing means for changing sequentially the activation phase of the drive signals to said plural-phase windings by said plurality of first power transistors and said plurality of second power transistors in the positive direction in response to time; phase correcting means for correcting the activation phase of the drive signals to said plural-phase windings in response to either or both of the rising and falling edges of said position signal; and mode select means for selecting said rotation control means in response to occurrences of said position signal, and said rotation control means comprises: time measuring means for measuring a time interval T 0 which responds with an interval of said position signal; and phase adjusting means for changing the activation phase of the drive signals to said plural-phase windings in time in response to the measured value of said measuring means.