Modern Methods of Torque Control on Two-Drum Winders

This paper will deal with various methods of torque control for two-drum winders, some that have been more common in the past and others that have come into use in recent years. Before looking into specific methods of torque control, consideration will be given as to just what function the winder (any winder) performs, the type of operation required on two drum winders to accomplish this function, and how torque control can give this desired operation. Other factors influencing the quality of the rewound roll such as sheet quality, back-stand tension control, and rider roll pressure control will be discussed briefly. Areas (including grades and quality of web) where high back-stand tension or rider roll pressure cannot be utilized for roll density and therefore roll quality will be explained to emphasize the need for positive dependable torque control. Various methods of torque control will be considered along with advantages and disadvantages of each. Finally, results of automatic torque control for two specific installations will be discussed indicating the improved roll quality and ease of operation that has been obtained.