Results of an analysis of the operation of the DSV-40 furnace during the melting period and various values of average active power and the weight of the burden fill-up. It is shown that the furnace work with nominal loading weight (40-45) t results into increasing use of electric power and lessening the efficiency of the furnace. The increasing of burden fill-up mass to (55-60) t with the nominal power of transformer 16 MV multiplied by (times) A allows improvement of the furnace performance with the average active power of the melting period (12. 5-13. 5) MW. The rational values of power during oxidation (9. 0-10. 0) MW and reoxidation (5. 5-6. 0) MW periods of carbon steels and slightly alloyed steels are given.