The Main Stages of Development of an Electric Drive of a Cold Rolling Mill

Abstract

This article discusses selection of variables of electrical power equipment and variables of adjusting feedbacks of a control system of heavy-duty equipment using sequential partial optimization. The stages of the proposed procedure as well as its evaluation are exemplified by electric drive of cold rolling mill. It has been demonstrated that the best effect is achieved at the second stage due to application of elongated motor; herewith, it is possible to decrease inertia by about two times and the total transient time by about 25–30%. Practical design methods of electrical-power equipment of high precision drives can be supplemented by certain stages. This is very important for equipment operating in wide range of loads on the working shaft (more than four to five rated values) and/or that contains elements with mechanical compliance in control channel. By means of appropriate selection of the reduction ratio, it is possible to decrease significantly the influence of resonant maximums, which is necessary if the mechanical part is to meet requirements for quality of adjustment of a sequential correcting device of a conventional subordinate process-control circuit of a metallurgical electric device. The proposed procedure can be successfully applied also in systems with conventional variables for mechanisms operating with frequent starts/brakes. For instance, getting rid of ratios of rotor length to its diameter that are conventional for an asynchronous motor in some cases permits losses to be approximately halved.