| 摘要 |
PURPOSE:To prevent faulty rotating speed control, by a method wherein a present measured result is outputted as a control information when the result of measurement of the rotating speed of a motor is within a specified range while the result of a past measurement is outputted from a memory as the control information when the result of measurement of the rotating speed of the motor is not within the specified range. CONSTITUTION:When a starting command is outputted, a current control unit 5 supplies a spindle motor 3 with a predetermined driving current. When the spindle motor 3 is rotated, the period of the motor 3 is measured by a period measuring unit 4 and the result of the measurement is outputted to a memory 7, a period inspecting unit 8 and a periodical data selecting unit 9. The memory unit 7 outputs the result of measurement, stored at the latest measurement, to the periodical data selecting unit 9. The period inspecting unit 8 outputs a command to the periodical data selecting unit 9 to output the output of the period measuring unit 4 to a current control unit 5 when the result of measurement of the period measuring unit 4 is within a specified range. The period inspecting unit 8 outputs a command to the periodical data selecting unit 9 to select the output of the memory unit 7 when the result of measurement of the period measuring unit 4 is out of the specified range. |
