Hopkinson, John

Hopkinson, John
b. 27 July 1849 Manchester, England
d. 27 August 1898 Petite Dent de Veisivi, Switzerland
English mathematician and electrical engineer who laid the foundations of electrical machine design.
After attending Owens College, Manchester, Hopkinson was admitted to Trinity College, Cambridge, in 1867 to read for the Mathematical Tripos. An appointment in 1872 with the lighthouse department of the Chance Optical Works in Birmingham directed his attention to electrical engineering. His most noteworthy contribution to lighthouse engineering was an optical system to produce flashing lights that distinguished between individual beacons. His extensive researches on the dielectric properties of glass were recognized when he was elected to a Fellowship of the Royal Society at the age of 29. Moving to London in 1877 he became established as a consulting engineer at a time when electricity supply was about to begin on a commercial scale. During the remainder of his life, Hopkinson's researches resulted in fundamental contributions to electrical engineering practice, dynamo design and alternating current machine theory. In making a critical study of the Edison dynamo he developed the principle of the magnetic circuit, a concept also arrived at by Gisbert Kapp around the same time. Hopkinson's improvement of the Edison dynamo by reducing the length of the field magnets almost doubled its output. In 1890, in addition to-his consulting practice, Hopkinson accepted a post as the first Professor of Electrical Engineering and Head of the Siemens laboratory recently established at King's College, London. Although he was not involved in lecturing, the position gave him the necessary facilities and staff and student assistance to continue his researches. Hopkinson was consulted on many proposals for electric traction and electricity supply, including schemes in London, Manchester, Liverpool and Leeds. He also advised Mather and Platt when they were acting as contractors for the locomotives and generating plant for the City and South London tube railway. As early as 1882 he considered that an ideal method of charging for the supply of electricity should be based on a two-part tariff, with a charge related to maximum demand together with a charge for energy supplied. Hopkinson was one the foremost expert witnesses of his day in patent actions and was himself the patentee of over forty inventions, of which the three-wire system of distribution and the series-parallel connection of traction motors were his most successful. Jointly with his brother Edward, John Hopkinson communicated the outcome of his investigations to the Royal Society in a paper entitled "Dynamo Electric Machinery" in 1886. In this he also described the later widely used "back to back" test for determining the characteristics of two identical machines. His interest in electrical machines led him to more fundamental research on magnetic materials, including the phenomenon of recalescence and the disappearance of magnetism at a well-defined temperature. For his work on the magnetic properties of iron, in 1890 he was awarded the Royal Society Royal Medal. He was a member of the Alpine Club and a pioneer of rock climbing in Britain; he died, together with three of his children, in a climbing accident.
Principal Honours and Distinctions
FRS 1878. Royal Society Royal Medal 1890. President, Institution of Electrical Engineers 1890 and 1896.
7 July 1881, British patent no. 2,989 (series-parallel control of traction motors). 27 July 1882, British patent no. 3,576 (three-wire distribution).
1901, Original Papers by the Late J.Hopkinson, with a Memoir, ed. B.Hopkinson, 2 vols, Cambridge.
Further Reading
J.Greig, 1970, John Hopkinson Electrical Engineer, London: Science Museum and HMSO (an authoritative account).
—1950, "John Hopkinson 1849–1898", Engineering 169:34–7, 62–4.

Biographical history of technology. - Taylor & Francis e-Librar. . 2005.

Игры ⚽ Нужно решить контрольную?

Look at other dictionaries:

  • Hopkinson, John — ▪ British physicist born July 27, 1849, Manchester, Eng. died Aug. 27, 1898, Mount Petite Dent de Veisivi, Switz.       British engineer and physicist who invented the three wire system for electricity distribution and improved the design and… …   Universalium

  • John Hopkinson — Nacimiento 27 de julio de 1849 Manchester Fallecimiento 27 de agosto de 1898 Val d Herens, Suiza Nacionalidad Británico …   Wikipedia Español

  • John Hopkinson — (* 28. Juli 1849 in Manchester; † 27. August 1898 in der Schweiz) war ein britischer Physiker und Elektroingenieur. Das magnetische Äquivalent zum ohmschen Gesetz ist nach ihm benannt (hopkinsonsches Gesetz). John Hopkinson starb am 27. Augus …   Deutsch Wikipedia

  • Hopkinson — Hopkinson, John, Ingenieur, geb. 27 Juli 1849 in Manchester, gest. 27. Aug. 1898 bei einer Bergbesteigung in der Schweiz, studierte in Cambridge, promovierte 1870 in London, arbeitete 1872 bis 1878 bei der Leuchtturm Ausrüstungsfirma Chance and… …   Meyers Großes Konversations-Lexikon

  • John Hopkinson — Infobox Scientist name = PAGENAME box width = image width =150px caption = PAGENAME birth date = July 27 1849 birth place = Manchester death date = August 27 1898 death place = Val d Herens, Switzerland residence = citizenship = nationality =… …   Wikipedia

  • John Hopkinson — (28 juillet 1849 27 août 1898) était un physicien anglais. Hopkinson est devenu célèbre grâce à ses travaux sur les applications de l électricité et du magnétisme sur des sujets tels que les dynamos et les électroaimants. Il est également le… …   Wikipédia en Français

  • Hopkinson — is a surname, and may refer to:* Austin Hopkinson, British politician * Carl Hopkinson, English cricketer * Bertram Hopkinson, British engineer * Charles Hopkinson, American artist * Francis Hopkinson, American writer and signer of the… …   Wikipedia

  • John Field — um 1835 John Field (* 26. Juli 1782 in Dublin; † 23. Januar 1837 in Moskau) war ein irischer Komponist und Pianist. Er gilt als der Erfinder des Nocturnes …   Deutsch Wikipedia

  • Hopkinson — ist der Familienname von Eddie Hopkinson (1935–2004), englischer Fußballspieler Francis Hopkinson (1737 1791), einer der Gründerväter der USA John Hopkinson (1849 1898), britischer Physiker und Elektroingenieur Nalo Hopkinson (* 1960), kanadische …   Deutsch Wikipedia

  • Hopkinson Smith — (born 1946) is an American lutenist.Born in New York, he graduated from Harvard with Honors in Music. He came to Europe in 1973 to study with Emilio Pujol, a great pedagogue in the highest Catalan artistic tradition, and also Eugen Dombois, whose …   Wikipedia

  • Hopkinson's law — is the magnetic counterpart to the electrical Ohm s law. The law is named after the British electrical engineer, John Hopkinson.It states that the magnetomotive force is equal to the product of the magnetic flux and the reluctance of the circuit …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”