The tension of the unwinding is controlled by the brake torque of the magnetic powder brake. As the continuous reduction of the winding diameter, the braking torque must be continuously reduced. The torque of the magnetic powder brake is automatically controlled by the tension controller
so that the tension is constant.
The final winding speed is normally higher than the line speed of the material, so the magnetic powder clutch working in a slip state, the tension is controlled by the torque of the powder clutch. In order to keep the tension, The torque of the powder clutch brake must be increased or decreased according to the size of the web.