- John Hopkinson
Infobox Scientist
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birth_date =July 27 1849
birth_place =Manchester
death_date =August 27 1898
death_place =Val d'Herens ,Switzerland
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nationality = British
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field =physics
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known_for =electrical engineering
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footnotes =John Hopkinson, FRS, (
July 27 1849 –August 27 1898 ) was a Britishphysicist , electrical engineer,Fellow of the Royal Society and President of the IEE twice in 1890 and 1896. He invented the three-wire (three-phase ) system for the distribution of electrical power, for which he was granted apatent in 1882. He also worked in many areas ofelectromagnetism andelectrostatics , and in 1890 was appointed professor ofelectrical engineering atKing's College London , where he was also director of theSiemens Laboratory . [Oxford Dictionary of National Biography : "Hopkinson, John" by T. H. Beare]Hopkinson's law , the magnetic counterpart toOhm's law , is named after him.Life and career
John Hopkinson was born in
Manchester , the eldest of 13 children. His father, also called John, was amechanical engineer . He was educated at Queenwood School in Hampshire andOwens College in Manchester. He won a scholarship toTrinity College, Cambridge in 1867. He graduated in 1871 asSenior Wrangler , having placed first in the demandingCambridge Mathematical Tripos examination. During this time he also studied for and passed the examination for a BSc from theUniversity of London .Hopkinson could have followed a purely academic career but instead chose engineering as his vocation.
After working first in his father's engineering works, Hopkinson took a position in 1872 as an engineering manager in the
lighthouse engineering department of Chance Brothers and Company inSmethwick . In 1877 Hopkinson was elected aFellow of the Royal Society in recognition of his application of Maxwell's theory ofelectromagnetism to problems ofelectrostatic capacity and residual charge. In 1878 he moved toLondon to work as a consulting engineer, focusing particularly on developing his ideas about how to improve the design and efficiency ofdynamos . Hopkinson's most important contribution was his three-wire distribution system, patented in 1882. In 1883 Hopkinson showed mathematically that it was possible to connect two alternating current dynamos in parallel — a problem that had long bedeviled electrical engineers. [ [http://www.archive.org/details/originalpaperson00hopkrich Original papers on dynamo machinery and allied subjects (London, Whittaker, 1893)] ]Accidental death
Hopkinson and three of his children were killed in 1898 in a mountaineering accident on Mount Petite Dent de Veisivi,
Val d'Herens ,Switzerland .As a memorial to John Hopkinson and his son, the 1899 extension to the Engineering Laboratory in the
New Museums Site ofUniversity of Cambridge was named after him. A plaque commemorating this is fixed to the wall inFree School Lane . [ [http://www.geocities.com/bioelectrochemistry/hopkinson.html John Hopkinson biography] ]ee also
*
Electric motor
*Three-phase electric power
*Polyphase system
*Bertram Hopkinson References
External links
* [http://www.archive.org/search.php?query=creator%3A%28John%20Hopkinson%29 Works by John Hopkinson] at
Internet Archive . Scanned, illustrated original editions.
* [http://www-g.eng.cam.ac.uk/125/noflash/1875-1900/hopkinson_john.html John Hopkinson]
* [http://www-groups.dcs.st-and.ac.uk/~history/Biographies/Hopkinson.html John Hopkinson Biography]
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