War of Currents

In the "War of Currents" era (sometimes, "War of the Currents" or "Battle of Currents") in the late 1880s, George Westinghouse and Thomas Edison became adversaries due to Edison's promotion of direct current (DC) for electric power distribution over the alternating current (AC) advocated by Westinghouse and Nikola Tesla.

During the initial years of electricity distribution, Edison's direct current was the standard for the United States and Edison was not disposed to lose all his patent royalties. Direct current worked well with incandescent lamps that were the principal load of the day, and with motors. Direct current systems could be directly used with storage batteries, providing valuable load-levelling and backup power during interruptions of generator operation. From his work with rotary magnetic fields, Tesla devised a system for generation, transmission, and use of AC power. He partnered with George Westinghouse to commercialize this system. Westinghouse had previously bought the rights to Tesla's polyphase system patents and other patents for AC transformers from Lucien Gaulard and John Dixon Gibbs.

Several undercurrents lay beneath this rivalry. Edison was a brute-force experimenter, but was no mathematician. AC cannot really be understood or exploited without a substantial understanding in mathematics and mathematical physics, which Tesla had. Tesla had worked for Edison but was undervalued (for example, when Edison first learned of Tesla's idea of alternating-current power transmission, he dismissed it: "[Tesla's] ideas are splendid, but they are utterly impractical."). Bad feelings were exacerbated because Tesla had been cheated by Edison of promised compensation for his work. Edison would later come to regret that he had not listened to Tesla and used alternating current.

(source: From Wikipedia, the free encyclopedia)