The first electrical devices were powered by relatively weak direct-current motors. Alternating current was known since 1835, when Hippolyte Pixii built the first alternator, but the technology was deemed too new, too raw, to have much practical use. Alternating current crossed the threshold of practicality starting in the 1880s, when Sabastian Ferranti, and engineering at Siemens Brothers in London created the first transformer, allowing alternating current to power everything from street lamps to trams. In the United States, the AC revolution would be led by George Westinghouse

On this day, November 30, in 1886, after securing the North American rights to AC power generation for $50,000, George Westinghouse created the first commercial alternating current power plant in the U.S.

Westinghouse was less an engineer than a brilliant businessman. Realizing the great advantage of AC power, Westinghouse built his early system using Siemens alternator and a transformer based on the designs of Lucien Gaulard and John Gibbs. Nicola Tesla, another AC pioneer, would be one of its engineers, initiating the “War of the Currents” between Westinghouse and Thomas Edison.