GB190807923A - Improvements in or relating to Electric Furnaces - Google Patents

Abstract

7923. Nathusius, H., and Westdeutsche Thomasphosphatwerke Ges. April 9. [Patent of Addition to No. 7188, A.D. 1908.] Electric furnaces.-The circuit connexions of an electrode furnace of the type described in Specification No. 7188, A.D. 1908, are arranged so that the distribution of current through the metal bath may be varied by switching-out separate electrodes or by varying the resistance in series with them. The connexions for a three - phase furnace are shown in Fig. 4. The upper electrodes a, b, c are connected to the three phase-windings I, II, III of the generator, and the lower electrodes d, e,f are connected through switches and variable resistances to the neutral point of the generator. In a furnace operated on the three-wire system, two upper electrodes are connected to the outers and the lower electrodes through switches and resistances to the middle wire. When a simple alternating or continuous current is used, a single upper electrode may be connected to one pole of the generator, and the lower electrode or electrodes through switches and resistances to the other pole, or two upper electrodes a, c, Fig. 1, may be connected to the two poles of the generator x, the lower electrodes d, f being then arranged to be connected together at will through a switch and variable resistance y, as shown. By these means the heat may be concentrated at any desired part of the bath ; and also, in the case of alternating currents, particularly three-phase currents, a circular motion of the charge takes place.