| 摘要 |
<p>A cord tension control apparatus includes a brushless motor (M) generating counter electromotive force, a rectifier circuit (2) connected to a winding of the brushless motor (M), and a constant current circuit (3) connected to the rectifier circuit (2). A voltage circuit (4) giving forward direction bias voltage is inserted between the constant current circuit (3) and the rectifier circuit (2). Even when the rotation speed of the motor (M) is lowered and the output voltage is lowered, at least the forward direction bias voltage generated by the voltage circuit (4) is applied to the constant current circuit (3). Accordingly, there is no non-operation state of the constant current circuit (3) when the rotation speed of the motor (M) is lowered. A constant current can be assured and the tension of cords can be controlled to be always constant (Fig. 1).</p> |
