Tension control and winder applications exist in virtually all industries. Because of our simple, flexible speed adjustment and control characteristics, Dynamatic® Eddy Current technology provides an inexpensive and accurate means of solving tension control challenges.
Constant tension winders are typically divided into two main categories: centerwinds and surface winds. The determining characteristic is the point of power input. On centerwinds, the power is introduced at the core shaft or center of the roll. On surface winders, the power is applied to the surface of the winding roll.
Surface winders normally make use of one or two drums against which or upon which the roll is wound. Torque applied to the drum shaft always reacts with the fixed radius of the drum to provide tension. This radius is constant regardless of wound roll diameter. Therefore, constant torque at the drum will result in constant tension on the web. Surface winders are constant torque drive applications with relatively straightforward speed controls involved.
Centerwinds are significantly more complex. As the web is wound, the diameter (or radius) increases. The circumference also increases. With a constant FPM (foot per minute), the winding roll will be forced to decrease in speed as the roll builds up. Thus, the winder drive is faced with an ever-increasing torque arm and a continually decreasing RPM requirement. To maintain constant tension on a centerwind, a drive must deliver the proper value of torque at the proper RPM at any instant in the roll buildup.
For further information or details on these and other tension and winder adjustable speed applications, please download our applications guide or contact one of our application specialists.