Electric melting furnaces

The paper deals with electric melting furnaces mainly from the view point of the electrical engineer. It describes the seven main types which have become established and standardised. It covers questions which are often raised by electric supply engineers in relation to the kind of load which these furnaces take from the electric mains. Some notes on working conditions have also been included. A special protective system for high frequency furnaces has been described in some detail; also an all-electric regulator for are furnaces with an indication of the historical background in the development of this apparatus. The paper does not dealwith the electrical theory on which the various furnace designs are based, nor with metallurgical matters, refractory linings, thermal efficiencies and such like; these matters have already beenwell covered elsewhere, especially with respect to high frequency (coreless induction) furnaces and arc furnaces.