Improving the Load Balancing System of the Rolling Mill Stand Drives

Abstract

Matching load modes of the drives of the top and bottom rolls of rolling mill stands is an important scientific and practical problem. Solving it is relevant for the drives of reversing stands of modern plate mills. The solution complexity is caused by the need for matching load balancing mode with the mode of forming a bend of the head end of the strip plate at the stand outlet. The oscillograms of the speeds and torques of the top and bottom roll drives have been analyzed for the existing drive control algorithm. The double or more difference in the drive torques in roughing passes has been confirmed. Thereat, the bottom roll drive torque reaches the limiting level, and the top roll drive switches to the generator mode. A technique for matching the modes of the upward bending and the drive load distribution systems has been proposed. A control technique has been developed, ensuring a forced matching of speeds. The diagram of an adaptive load-distributing controller is given. The oscillograms of the drive torques have been analyzed for the technique developed. Conclusions have been made on improving the accuracy and reducing the time for matching the torques. Information is given on the technical effect of implementing the developed technique on a 5000 plate mill.