 In 1891 Westinghouse built a hydroelectric AC power plant, the Ames Hydroelectric Generating Plant.The plant supplied power to the Gold King Mine 3.5 miles away.This was the first successful demonstration of long-distance transmission of industrial-grade alternating current power and used two 100 hp Westinghouse alternators, one working as a generator producing 3000-volt, 133-Hertz, single-phase AC, and the other used as an AC motor.