Wide-range D-C center-wind drive

Continuous-process machines are employed in many different industries. Material processed on these machines must be handled, moved, and stored. One of the most commonly used packages is the reel, or roll, because material from this kind of package can be quickly unwrapped, processed, and then rewound. Several kinds of electric drives have been designed to perform the operation of rewinding material. This paper will deal with one particular class of constant-tension rewind drives. Direct-current motor drives are widely used for constant-tension rewind stands in which the roll being wound is driven by a motor attached to its shaft. When the d-c motor is controlled by varying its field, it exhibits an interesting property which allows for very economical drive design as well as economical machine design. One of the limitations of d-c motor rewind stands had been the limited speed range that is possible with field control of d-c motors. This paper will discuss a means for extending the range of a d-c winder drive.