Calculation method of an unwinding machine electric drive's breaking torque alteration on a rebar production line

The paper proves possibility to increase quality of reinforcing wire by means of enhancement of the unwinding machine electric drive control system at the rebar production line. An analytical equation for the required alteration in the unwinding machine electric drive's breaking torque needed to stabilize wire tension at a specified level between the roller-straightening device and profile stand is offered. Tension variations due to breaking torque alteration in the active control system of the unwinding machine electric drive have been compared; calculation with the proposed equation has proved that the wire fill-in radius of the reel within an active control system is decreased during unwinding process accompanied by a considerable decline in wire tension. On the contrary, if offered equation is used to vary breaking torque of the drive in response to the fill-in radius decrease, wire tension is stabilized. A method for calculation of efficient braking torque alteration of the unwinding machine electric drive at varying wire fill-in radius of the reel has been developed.