The monograph is devoted to the design and research of multi-electrode furnace installations for the production of steel and alloys. Models of magnetohydrodynamic and thermal processes in furnace melts at constant and variable electro-magnetic fields are given. Basic regularities of melt flows in baths of furnace plants, as well as indicators of their technological and economic efficiency are described. Variants of construction of power supply systems of furnace complexes using converting equipment are considered.