| 摘要 |
PROBLEM TO BE SOLVED: To shorten the starting time of a motor and to stabilize the fixed- speed rotation of the motor. SOLUTION: A feedback signal generating section 28 generates a feedback signal by substantially integrating a speed difference signal Sr from a speed difference signal generating section 22 and a phase difference signal Sp from a phase difference signal generating section 24, and a current supply control section 17 controls the drive current supplied to a motor M based on the feedback signal. When the section 28 generates the feedback signal, a serial circuit of a diode 33 and a transistor 34 are provided in parallel with the fourth capacitor 31b of the section 28. When the motor M is being started, the time constant of the section 28 is made smaller through connecting the diode 33 to the capacitor 31b by turning on the transistor 34. When the rotating speed of the motor M detected by means of a rotating speed detecting section 19 reaches a set value, the time constant of the section 28 is made larger by disconnecting the diode 33 from the capacitor 31b by turning off the transistor 34 with an actuation signal LD from an actuation signal generating section 26. |
