Automatic substations for industrial plants

C S. Butcher: One of the earliest installations of automatic equipment in industrial plants was in the motor car industry in Detroit, where two 1,500 kw. motor generators are used to augment the power supplied by a steam plant. The steam plant is located at one end of the manufacturing aisle, which is some 600 ft. or so long, and a very heavy bus runs through a tunnel from the power house to the load, which is distributed along the bus quite uniformly. It was found, in making a study of the power plant, that the steam costs were very high, however in the wintertime the exhaust steam is used for heating, and in working out the economics of the problem it was found that if substations were located along the bus, the steam plant, during the summer months could be shut down and considerable saving realized by purchasing power.