JPS54107860A - Speed controller for upper and lower rolls - Google Patents

Abstract

PURPOSE:To simply, exactly control the roll speed correspondingly to the tension, by taking a certain stand as the reference stand, by providing the stands except the reference stand with the drooping characteristic of the motor, and by utilizing this, for correcting the roll speed of the stands except the reference stand. CONSTITUTION:The third stand S3 in taken as the reference stand; and when the tension on the exit side becomes large, increases the torque of the motor 8 of each of upper and lower work rolls 4, 5, of the fourth stand S4 at the down stream, and the revolving speed goes down. Since the drooping characteristic is given to the motor on the low speed side of the fourth stand S4, the revolution of the motor 8, of the work roll 5 on the low speed side, goes down. This revolving speed is detected by the speed meter 7, and is inputted to the speed controller 6 on the high speed side, and is multiplied by the ratio of circumferential speeds, and is made the set speed for the motor on the high speed side; and then, the circumferential speed of the work roll 4 on the high speed side is reduced following to the work roll 5 on the low speed side, keeping constant the ratio of circumferential speeds, and making zero the drooping characteristic of the motor; hereby, the control is carried out for keeping the ratio of circumferential speeds previously operated and set.