GB191067A - Improved method of and means for feeding electric furnaces with current - Google Patents

Abstract

191,067. Quattrino, L. Dec. 29, 1921, [Convention date]. Furnace details.-An electric furnace 1 is fed bv a transformer T, the primary P of which is inserted in a circuit controlled by a regulating transformer t, the primary of the regulating transformer being connected to the supply mains L in parallel with the primary of the furnace transformer, and the secondary s being divided into sections which may be inserted into the circuit of the primary P in varying numbers and opposite directions. In this way the power absorbed by the furnace is kept constant. The sections of the secondary s are connected to contacts 2 of a switch provided with movable brushes 3, 4 operated by a reversible motor 6 controlled by an electromagnetic switch 7, the coil 10 of which is energized by the secondary 9 of a second adjustable transformer acted upon by the current flowing through the primary P. The brushes of the switch to which the sections of the secondary s are connected are preferably arranged so that they insert a resistance or impedance between the contacts 2 during their passage from one contact to the next. In the case of polyphase furnaces, each phase is adjusted independently by a device of the type described.