Method and apparatus for electrically balancing three-phase arc discharge furnaces

摘要

A method and apparatus for electrically balancing the phases of a three phase arc furnace, the furnace having a vessel containing a molten bath, three electrodes above the bath, and a transformer arrangement composed of three phases, each phase including a winding, the transformer arrangement being connected to the electrode so that each electrode conducts an arc current proportional to the voltage across the winding of a respective phase, by the steps of: matching the voltages between the electrodes and the bath to one another by adjusting the spacing between at least one electrode and the bath; and establishing symmetry among the arc currents by: varying the voltage across at least one phase winding by a selected increment; measuring the arc current amplitude in the electrode associated with the at least one phase winding after each variation step; and repeating the steps of varying and measuring until the differences between the arc current amplitudes of the three electrodes are less than a given value.