Digital linear electrical drive for metal strip coil telescopeness control

The final step of the metal rolling process of thin strips is usually winding. By the influence of different disturbances, some layers of the coil have displacements, one about other. The coil borders then become uneven. This phenomenon is called `telescopeness´ and is not desirable because protruding edges of the wound strip can be bent and crumpled under further coil processing. It is especially important for soft metal strips, e.g. aluminimum. Several methods can be used to remove or limit this telescopeness. The paper discusses these methods, and a new method of telescopeness control is proposed. It is based on the use of controlled linear induction motors (LIM). The principle of operation of such a system is described