Nikola Tesla

The engineer who made alternating current practical.

Nikola Tesla (1856–1943) was a Serbian-American engineer whose work on alternating current systems shaped how electricity is generated and distributed. Born in what is now Croatia, he emigrated to the United States in 1884 and briefly worked for Edison.

The central contribution

Tesla's polyphase AC induction motor solved the problem that had held AC back. DC motors were well understood; a practical AC motor was not. His design used a rotating magnetic field produced by multiple out-of-phase currents, needing no brushes or commutator. That made AC useful for industry, not just lighting, and settled the argument.

The current war

Edison had invested in DC. DC cannot be transformed to high voltage easily, so it suffers heavy transmission losses and needed generating stations roughly every mile. AC can be stepped up for transmission and down for use. Westinghouse licensed Tesla's patents and won the 1893 Chicago World's Fair contract and the Niagara Falls project. The grid is AC because the physics favoured it.

Separating record from myth

Tesla's genuine achievements are substantial: the induction motor, polyphase systems, the Tesla coil, and early radio work that the US Supreme Court partly recognised in 1943. He also promoted schemes — notably worldwide wireless power transmission at Wardenclyffe — that were never demonstrated and are not physically practical as described.

Popular accounts tend to overstate the second category and treat every unrealised claim as suppressed genius. The reliable measure is what was built and worked, and by that measure his contribution is large enough without embellishment.