ELEVATION CONTROL SYSTEM FOR ARC FURNACE ELECTRODE

摘要

PURPOSE:To prevent the damage of a furnace wall by detecting arc current for elevating an electrode quickly when excess current is detected. CONSTITUTION:A current transformer 9 and a voltage transformer 10 are provided on the secondary side of a furnace transformer 3, and their output signals are converted into DC voltages, which are compared through an adjusting resistor 13. A speed reference signal V1 is taken out from this resistor 13 and compared with a speed return signal V2 for forming a speed control circuit of an electrode 2. Here, in a quick elevation circuit of the electrode, arc current is given to a rectifier 15 through current transformers 9 and 14, and the rectified signal is divided in voltage to be input to an amplifier 17. When an output signal is obtained from the amplifier 17, a field-effect transistor 18 is connected, and a quick elevating signal V3 for the electrode is given to a speed control circuit.