New solution of tangent rewinder drive in the board factory

The paper presents the reconstruction and modernization of the tangent rewinder performed in the board factory „Umka”, near Belgrade, Serbia. The reconstruction included partial reconstruction of the mechanical part, integration of the new system for slitting paper web in longitudinal direction, and complete replacement of the electrical drive and control system. With the proper connection of frequency converters of the winder and unwinder drives, efficient energy exchange between the drives trough common DC link is achieved (Load Sharing) during the operation mode. While stopping, the drives are breaking and trough integrated energy recuperator, energy is returned into supply network. In this way, energy consumption of the rewinder is reduced to an extent required to cover losses in motors, frequency converters and motion resistances. Control system is realized with PLC, while communication between controllers, frequency converters, presductors, absolute encoder and control panels uses profibus protocol. This system, with integrated application software, enables realization of all requirements to accomplish desirable quality and structure of rewound rolls. The requirements are: web tension at the unwinder side, pressure of rider roll as a function of shipping roll diameter and rewinding hardness - on the base of winder drive torque difference as a function of shipping roll diameter. While rewinding, the control system measures the length of shipping roll and calculates its weight. With the integration of new drives, the rewinder capacity is extended, based on increased rewinding speed and better time utilization, owed to the user friendly user interface. Faculty of Electrical Engineering in Belgrade has completed the project and application software, supervision and commissioning.