ELECTRODE ELEVATION CONTROL SYSTEM FOR A.C. ARC FURNACE, A.C. ARC FURNACE AND OPERATION METHOD OF A.C. ARC FURNACE

摘要

PROBLEM TO BE SOLVED: To provide an electrode elevation control system for an A.C. arc furnace capable of eliminating a steady-state difference conventionally generated in a current, setting part of a voltage/current control circuit to realize correct control and capable of efficiently dissolving a processed object. SOLUTION: The voltage/current control circuit 30 carries out proportional integration control (PI operation) including an integration element as an element of a calculation formula for calculating a targeted current value. An electrode 50 is vertically movably attached to a furnace housing. This electrode elevation control system for an A.C. arc furnace also has an electrode elevating device 40 for vertically moving the electrode 50 in order to adjust an arc resistance value proportional to the distance between the electrode 50 and a scrap of a processed object. The electrode elevating device 40 vertically moves the electrode 50 according to the targeted current value calculated by the control circuit 30 and thereby adjusts the arc resistance value.