METHOD FOR CONTROLLING DRIVING OF PINCH ROLL OF CONTINUOUS CASTING MACHINE

摘要

PURPOSE:To enable always stable control of driving by connecting a load for compensating a blind zone in parallel with a DC motor, conducting electricity to the load for compensating blind zone when the load of the motor is light and eliminating substantially the blind zone in controlling the conduction of a rectifier circuit. CONSTITUTION:A load 5 for compensating a blind zone and DC motors 3- are connected in parallel between both output terminals of a rectifier circuit 4 of an AC power source 10 and the circuit 4 is controlled by a control circuit 7 for the phase of electricity condution. When the current value detected by a current transformer 64 is smaller than the current value set by a setter 62, a comparator 61 applies a command signal for forward or backward run to a gate control circuit 6a or 6b then a switching element 52a or 52b is made conducting and the current from the circuit 4 is shunted via a variable resistor 51a or 51b of a bypass circuit. The load is then exerted on the circuit 4 and the blind zone in the phase control of the electricity conduction is substantially eliminated. The always stable control for the driving of pinch rolls is thus made possible.