Nikola Tesla: Chicago World’s Fair

Alternating Current Power Plant
at World’s Fair, Chicago, 1893.

Four of the twelve
1000 horse-power two-phase generators

Quite apart from the lighting plant, the Westinghouse Company showed at the World’s Fair a complete polyphase system. A large two-phase induction motor, driven by current from the main generators, acted as the prime mover in driving the exhibit. The exhibit, then, contained a polyphase generator with transformers for raising the voltage for transmission; a short transmission line; transformers for lowering the voltage; the operation of induction motors; a synchronous motor; and a rotary converter which supplied direct current, which in turn operated a railway motor. In connection with the exhibit were meters and other auxiliary devices of various kinds. The apparatus was in units of fair commercial size and gave to the public a view of a universal power system in which, by polyphase current, power could be transmitted great distances, and then be utilized for various purposes, including the supply of direct current. It showed on a working scale a system upon which Westinghouse and his company had been concentrating their efforts; namely, the alternating-current and polyphase system.It has been maintained with some plausibility that the most important outcome of the Centennial Exposition of 1876 was that the people of the United States there discovered bread. So it may be maintained with even more plausibility, that the best result of the Columbian Exposition of 1893 was that it removed the last serious doubt of the usefulness to mankind of the polyphase alternating current. The conclusive demonstration at Niagara was yet to be made, but the Wolrd’s Fair clinched the fact that it would be made, and so it marked an epoch in industrial history. Very few of those who looked at this machinery, who gazed with admiration at the great switchboard, so ingenious and complete, and who saw the beautiful lighting effects could have realized that they were living in an historical moment, that they were looking at the beginning of a revolution.

Adopted from “A Life of George Westinghouse,” by Henry G. Prout, 1921.