| 摘要 |
PURPOSE:To enable a strict control of a tension, in a system employing a motor for controlling the tension of a sheet or other sheet-shaped materials, by separating a mechanical loss current and a tension current from each other, and only the tension current is controlled. CONSTITUTION:An idle operation is carried out in a state to couple a motor 2 directly with a machinery. At that time, contacts B1 and B2 are brought into an open condition, and contacts A1 and A2 are set into a closing state to measure a relation between a mechanical loss current and a speed of a load machinery. The relation is stored in an operation circuit 9 for mechanical loss. When operating through a sheet or a string-shaped object, an optional speed of a d.c. motor 2 is detected in a manner to bring the contacts A1, A2 into opening and the contacts B1, B2 into closing, and a circuit 9 calculates a mechanical loss current 1m. The 1m is inputted to a current operational circuit 10, and produces a tension current It of Ia-Im between the Im and an armature current Ia. The It is compared with a reference tension signal, set by a tension setter 11, via the contact B2 to control a thyristor gate. |
