Improvement of Strip Thickness Accuracy by using ac Motor Drive Systems in Hot Strip mills

Abstract

This paper presents that, in hot strip finishing mills, AC motor drive systems improve the strip tension control performance which results in better strip thickness accuracy than DC motor drive systems. Recently the AC motors are more widely used in many industrial fields including steel making process because of their higher response of speed control, higher reliability, and easier maintenance than DC motors. Here we consider the effect of using AC motors as rolling main motors from a point of view of strip thickness accuracy. We analyse the relation between speed control response of the strip tension control system and strip thickness accuracy with use of the Bode diagram and non-linear simulation. As a result we show that the higher response of AC motor speed control system can achieve the smaller strip tension deviation, furthermore makes it possible to get higher response of gage control system which turns more accurate strip thickness. © 1995, The Institute of Electrical Engineers of Japan. All rights reserved.