LONG ARC OPERATION

摘要

For many years AC-arc furnaces usually have been operated with shorter electric arcs, using a maximum secondary voltage of up to 650 V. This was based on the limitation of the heat radiation relating to refractory wear and panel life time. With the development of the foaming slag practice, surrounding the electric arc, and of the water-cooled panels, this situation generally has changed. There is a clear trend to a furnace operation with longer electric arcs, with secondary voltages of up to 1.500 V. Meanwhile this has also been considered by the international standard ― IEC 60519-4 ―, where the upper limit of 1.000 V for the operation of electric arc furnaces has been revoked since December 1999.