Nikola Tesla was an mechanic.
Nikola Tesla ( Никола Тесла 10 July 1856 -- 7 January 1943 ) was a Serbian-American inventor , electrical engineer , mechanical engineer , physicist , and futurist who is best known for his contributions to the design of the modern alternating current ( AC ) electricity supply system . His alternating current ( AC ) induction motor and related polyphase AC patents , licensed by Westinghouse Electric in 1888 , earned him a considerable amount of money and became the cornerstone of the polyphase system which that company would eventually market .