The Two Currents
AC and DC have very different properties. Direct current flows in a single direction with constant
voltage. It cannot be transmitted far without losing energy. AC reverses direction many times per second. Easily transformed to high voltages, it can be transmitted over great distances with minimal power loss.
The Combatants
Thomas Edison
After inventing the light bulb in 1879, Edison developed
the entire DC system. In 1882 using money obtained from investors he
opened the Pearl Street generating station, heating and lighting a small
part of Manhattan. His company beat back the gas lighting companies
with effective propaganda, expanding rapidly.
Nikola Tesla
Tesla, in 1884, discovered the principle of the AC induction motor, the primary reason the War occurred. During a stroll in the park at sunset with a friend the design suddenly appeared to him as he was reciting a passage of Goethe's Faust:
"Mild it retreats, the day that’s left,
It slips away to claim new being.
Ah, that no wing from earth can lift
Me, closer and closer to it, striving!
A lovely dream, although it vanishes.
Ah! Wings of the mind, so weightless
No bodily wings could ever be so."
(Kline)
"As I uttered these inspiring words," Tesla later declared, "the truth was [suddenly] revealed. I drew with a stick on the sand the diagrams shown six years later in my address before the American Institute of Electrical Engineers… Pygmalion seeing his statue come to life could not have been more deeply moved. A thousand secrets of nature which I might have stumbled upon accidentally I would have given for that one which I had wrestled from her against all odds and at the peril of my existence.” (Seifer 22, 24, 27)
Soon Tesla began work on the entire AC system, patenting and lecturing on it.
George Westinghouse
In the mid-1880s, Westinghouse entered the scene. Because
of Edison’s monopoly on DC technology, Westinghouse bought the best
AC patents he could find, improved them, and showed his system's
capabilities to a select group of potential investors. Westinghouse soon
became Edison's biggest competitor because AC could be transmitted over
longer distances and did not require as much expensive copper.