The Carotron CTCW (Constant Tension Center Wind) Control is designed for use with a torque mode drive to provide constant tension control or taper tension control of a center driven winder. Web tension is regulated by controlling motor torque through varying levels of material roll diameter, line speed and line acceleration rate. These diameter, friction and inertia compensating torque signals are summed with other torque signals to further provide control of core tension, taper tension, stall tension and even Winder motor RPM when in the JOG mode. The CTCW can accept an external diameter signal or can calculate diameter from Line and Winder speed signals by an internal Radius Computer with memory. A +10 VDC reference is available for a direct contact rider roll compensator to measure diameter. The Line Speed signal input is isolated to allow use of existing feedback or process tachometers.