ENHANCING THE CONTROL SYSTEM OF PAYOFF MACHINE ELECTRIC DRIVE IN THE STEEL-REINFORCEMENT-PRODUCING ROLLING MILL
One of the reserves of steel reinforcement knurling improvement is enhancement of control system of electric drives in the machines of the reinforcement-producing rolling mills. Experimental and theoretical research carried out on the functioning mill ISF 5 OAO “MMK-METIZ” (OJSC) have showed that existing control system of payoff machine electric drive does not provide the required quality of the reinforcement knurling and needs to be enhanced. Unsatisfactory operation of the existing control system of ISF 5 payoff machine electric drive is associated with its disability to stabilize the wire tension between the payoff machine and leveling bridle machine when the radius of wire reeling is reduced. For the process conditions of the reinforcement production on ISF 5 mill we obtained analytical expression for calculation of the wire tension between the payoff machine and leveling bridle machine. We also found empirical and analytical expressions for studies of the payoff machine electric drive torque components and tension-forming forces as influenced by the wire reeling radius. We designed procedure of calculating the appropriate change in the payoff machine electric drive torque at change in the coil filling radius to keep the predetermined wire tension between the payoff machine and leveling bridle machine. We developed functional diagram of the control system of payoff machine electric drive and algorithm of electric drive torque task calculation which should be introduced to meet new technological requirements for the payoff machine electric drive. The design control system of the payoff machine electric drive will provide stability of predetermined wire tension between the payoff machine and leveling bridle machine at change in the coil filling radius, wire diameter and other process conditions of the reinforcement production, and will therefore provide the required knurling depth of the reinforcing wire.