Alcoa rectifier installation

IN 1938, 15 mercury arc rectifier units, with a total capacity of 82,500 kw, were placed in service by the Aluminum Company of America to supply d-c power for the electrolytic production of aluminum.¹ In the plant at Alcoa, Tenn., ten of these units were installed to supply two 45,000 ampere, 600 volt, d-c circuits. In the plant at Massena, N. Y., five units were installed to supply one such circuit. These installations are noteworthy as they marked the first application of power rectifiers in this country for the electrolytic production of metal. At that time the Alcoa installation was the largest concentration of rectifiers in the country, with the highest kilowatt capacity, installed in a single station and operating on a common bus. Since 1938, one unit was added to each station in space reserved for it. At Alcoa twelve additional units were installed in a second station; six of these were placed in service in May 1940, and six in January 1941. This paper will describe the Alcoa rectifier installations. The Massena station is practically identical with the first Alcoa installation except for the number of units.