| 摘要 |
PURPOSE:To prevent mechanical abrasion and noise from being generated, b providing a rotational control means for providing a constant rotation to compensate for the load fluctuation of a motor. CONSTITUTION:A fixing motor shaft 21 fixing a stator 26 is combined with a main pulley unit 22 containing a rotor 27 to constitute a motor 28. On a rotational control means 40, the input current value of the motor 48 is kept to be always detected, and in this manner, the rotational frequency fluctuation of the motor 48, namely, the load fluctuation is detected by current feedback to a constant low-speed-rotational control circuit 50 through a current transformer 46, and the gate of a transistor 45 is controlled by changing frequency per unit time, and the characteristic of a constant rotation is obtained by controlling the rotational speed due to the change of the frequency of voltage applied to a motor terminal. In this manner, the motor is not provided with reduction gears or the like, thereby mechanical abrasion and noise can be prevented from being generated. |
