Tesla, Nikola

SUBJECT AREA: Electricity

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b. 9 July 1856 Smiljan, Croatia

d. 7 January 1943 New York, USA

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Serbian (naturalized American) engineer and inventor of polyphase electrical power systems.

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While at the technical institute in Graz, Austria, Tesla's attention was drawn to the desirability of constructing a motor without a commutator. He considered the sparking between the commutator and brushes of the Gramme machine when run as a motor a serious defect. In 1881 he went to Budapest to work on the telegraph system and while there conceived the principle of the rotating magnetic field, upon which all polyphase induction motors are based. In 1882 Tesla moved to Paris and joined the Continental Edison Company. After building a prototype of his motor he emigrated to the United States in 1884, becoming an American citizen in 1889. He left Edison and founded an independent concern, the Tesla Electric Company, to develop his inventions.

The importance of Tesla's first patents, granted in 1888 for alternating-current machines, cannot be over-emphasized. They covered a complete polyphase system including an alternator and induction motor. Other patents included the polyphase transformer, synchronous motor and the star connection of three-phase machines. These were to become the basis of the whole of the modern electric power industry. The Westinghouse company purchased the patents and marketed Tesla motors, obtaining in 1893 the contract for the Niagara Falls two-phase alternators driven by 5,000 hp (3,700 kW) water turbines.

After a short period with Westinghouse, Tesla resigned to continue his research into high-frequency and high-voltage phenomena using the Tesla coil, an air-cored transformer. He lectured in America and Europe on his high-frequency devices, enjoying a considerable international reputation. The name "tesla" has been given to the SI unit of magnetic-flux density. The induction motor became one of the greatest advances in the industrial application of electricity. A claim for priority of invention of the induction motor was made by protagonists of Galileo Ferraris (1847–1897), whose discovery of rotating magnetic fields produced by alternating currents was made independently of Tesla's. Ferraris demonstrated the phenomenon but neglected its exploitation to produce a practical motor. Tesla himself failed to reap more than a small return on his work and later became more interested in scientific achievement than commercial success, with his patents being infringed on a wide scale.

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Principal Honours and Distinctions

American Institute of Electrical Engineers Edison Medal 1917. Tesla received doctorates from fourteen universities.

Bibliography

1 May 1888, American patent no. 381,968 (initial patent for the three-phase induction motor).

1956, Nikola Tesla, 1856–1943, Lectures, Patents, Articles, ed. L.I.Anderson, Belgrade (selected works, in English).

1977, My Inventions, repub. Zagreb (autobiography).

Further Reading

M.Cheney, 1981, Tesla: Man Out of Time, New Jersey (a full biography). C.Mackechnie Jarvis, 1969, in IEE Electronics and Power 15:436–40 (a brief treatment).

T.C.Martin, 1894, The Inventions, Researches and Writings of Nikola Tesla, New York (covers his early work on polyphase systems).

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