| 摘要 |
<p>PURPOSE:To decrease the abrasion of a belt and idlers by making the revolving speed of a motor as low as roughly equal to a ''low speed'' by a control means at the time when a tape is going to be run at a high speed. CONSTITUTION:A motor 1 is supplied with a driving power source from a power source 3 through a known control means 2. The means 2 detects the counterelectromotive force of the motor 1, and controls this so as to assume a reference value, thereby making the rotating speed of the motor 1 constant. This reference value is changed by whether an electric route 4 is closed or opened, and when it is closed, the motor 1 runs at a low speed. The switch 5 inserted in series to the route 4 is for changing over of the ''high speed'' and ''low speed'' of the constant running speed of the tape, and is operated to on when the tape speed is the ''high speed'' and to off when the ''low speed''. A switch 6 is turned on by the constant speed running operation of the tape, such as playback, and is operated to off at the tape high speed running such as fast forwarding mode other than this, and when the tape stops.</p> |
