| 摘要 |
PROBLEM TO BE SOLVED: To provide a DC brushless motor which enables reduction of power consumption and a turbo molecular pump, using the DC brushless motor. SOLUTION: In a turbo molecular pump, the rotation position of a rotor 4 is detected by a rotation sensor 11, and the rotation period of the rotor 4 is calculated by a detection circuit 12, according to the signals of the sensor 11. Excitation patterns generated by an excitation pattern generating circuit 13 consist of three drive signal patterns for drive stator coils U, V and W, the phase differences between the respective drive signal patterns are set precisely at 120 deg., and the periods of the signal patterns are identical to the rotation period of the rotor 4. As a result, the stator coils U, V and W are driven with the ideal excitation patterns. Furthmore, if the phases of the excitation patterns are shifted from the rotation reference position of the rotor 4, so as to drive the rotor with the phase which can minimize the power consumption of the motor, the power consumption can be further reduced. |
