Electric power problems in steel plants

Previously to September 1904, the capacity of electric power plants in American steel mills varied locally from 200 to 3000 kw. The largest units were of approximately 1000 kw. capacity, and only direct current at a pressure of 250 volts was used. Plans in contemplation over a year before 1904 resulted in the construction of the first steel mill power plant of any magnitude at the south works of the Illinois Steel Company. This plant consisted of. a 4000-kw. station composed of two 2000-kw. 25-cycle, three-phase, 2200-volt steam-engine-driven generators. It was put in operation during September 1904, and supplied two converter sub-stations, transformers for local alternating-current motors, and a 22,000-volt transmission line 10 miles long supplying alternating-current motors at a cement plant. Since 1904, many of the comparatively small electric power plants in steel mills have been increased to several times their original capacity.