A double-drum winder winds finished paper at high speed, and the roll it builds is never the same twice: the radius grows, the inertia climbs, and the center of mass shifts. If tension is left to drift, the web slackens or tears. Our control recomputes the torque demand continuously so the web sees the same tension from the empty core to the finished roll.
In practice this means the unwind roll runs automatic tension control, the rider roll regulates nip pressure against the building roll, and the bottom drums carry a controlled torque difference to set the winding hardness. Reversible control lets the same drive handle both winding and controlled reversal during thread-up and troubleshooting.
Combined with length and diameter counting and a controlled deceleration stop, the line reaches its finished roll diameter and stops cleanly — without the surge or slack that ruins a roll. These are the functions our drive package performs on a 5600 mm, 1500 m/min winder.