Editing Rotating magnetic field (section)

==History==

In 1824, the French physicist [[François Arago]] formulated the existence of rotating magnetic fields using a rotating copper disk and a needle, termed “[[Arago's rotations]].” English experimenters [[Charles Babbage]] and [[John Herschel]] found they could induce rotation in Arago's copper disk by spinning a [[horseshoe magnet]] under it, with English scientist [[Michael Faraday]] later attributing the effect to [[electromagnetic induction]].<ref>{{Cite book|last=Carlson|first=W. Bernard|url=https://books.google.com/books?id=5I5c9j8BEn4C|title=Tesla: Inventor of the Electrical Age|publisher=Princeton University Press|year=2013|isbn=978-1400846559|location=|pages=52–54}}</ref> In 1879, English physicist [[Walter Baily's Motor|Walter Baily]] replaced the horseshoe magnets with four electromagnets and, by manually turning switches on and off, demonstrated a primitive induction motor.<ref>{{Cite book|last=Carlson|first=W. Bernard|url=https://books.google.com/books?id=5I5c9j8BEn4C|title=Tesla: Inventor of the Electrical Age|publisher=Princeton University Press|year=2013|isbn=978-1400846559|location=|page=55}}</ref><ref name="Babbage (1825)">{{cite journal|last=Babbage|first=C.|author2=Herschel, J. F. W.|date=Jan 1825|title=Account of the Repetition of M. Arago's Experiments on the Magnetism Manifested by Various Substances during the Act of Rotation|url=https://archive.org/stream/philtrans03806447/03806447#page/n0/mode/2up|journal=Philosophical Transactions of the Royal Society|volume=115|pages=467–496|bibcode=1825RSPT..115..467B|doi=10.1098/rstl.1825.0023|access-date=2 December 2012|doi-access=free}}</ref><ref name="Thompson (1895)">{{cite book|last=Thompson|first=Silvanus Phillips|url=https://archive.org/stream/polyphaseelectri00thomuoft#page/n5/mode/2up|title=Polyphase Electric Currents and Alternate-Current Motors|publisher=E. & F.N. Spon|year=1895|edition=1st|location=London|pages=261|author-link=Silvanus Phillips Thompson|access-date=2 December 2012}}</ref><ref name="Bailey (1879)">{{Cite journal|last=Baily|first=Walter|date=June 28, 1879|title=A Mode of producing Arago's Rotation|url=https://books.google.com/books?id=85AOAAAAIAAJ&pg=PA286|journal=Philosophical Magazine|publisher=Taylor & Francis|volume=3|issue=1|pages=115–120|bibcode=1879PPSL....3..115B|doi=10.1088/1478-7814/3/1/318}}</ref><ref name="Vuckovic (2006)">{{cite journal|last=Vučković|first=Vladan|date=November 2006|title=Interpretation of a Discovery|url=http://www.doiserbia.nb.rs/img/doi/1451-4869/2006/1451-48690603202V.pdf|journal=The Serbian Journal of Electrical Engineers|volume=3|issue=2|access-date=10 February 2013}}</ref>

The idea of a rotating magnetic field in an [[AC motor]] was explored by the Italian physicist and electrical engineer [[Galileo Ferraris]] and the Serbian-American inventor and electrical engineer [[Nikola Tesla]].<ref>{{Cite book|last=Hughes|first=Thomas Parke|url=https://archive.org/details/networksofpowere0000hugh|title=Networks of power: electrification in Western society, 1880-1930|publisher=Johns Hopkins University Press|year=1983|isbn=9780801828737|location=Baltimore|page=117}}</ref> Ferraris, who did research about the theory and design of alternating-current machinery, built a working model for a classroom demonstration in 1885, but did not describe it publicly until 1888.<ref>{{Cite encyclopedia|last=|first=|url=https://archive.org/details/encyclopediaamer0011unse_f6t5/page/124/mode/2up|title=Ferraris |encyclopedia=Encyclopedia Americana: Falstaff to Francke|publisher=Scholastic Library|year=2004|volume=11|edition=International|location=Danbury, Connecticut|page=124}}</ref> Tesla attempted several (unsuccessful) designs and working models through the early 1880s before building a working prototype in 1887<ref>{{Cite book|last=Carlson|first=W. Bernard|url=https://books.google.com/books?id=5I5c9j8BEn4C|title=Tesla: Inventor of the Electrical Age|publisher=Princeton University Press|year=2013|isbn=978-1400846559|location=|pages=63–68}}</ref><ref>[https://edisontechcenter.org/tesladebunked.html Debunking the Tesla Myth]</ref><ref>{{Cite book|last=O'Neill|first=John|title=Prodigal Genius: The Life of Nikola Tesla|pages=55–58}}</ref> According to Ferraris principle of rotating magnetic field, Friedrich August Haselwander developed the first AC 3 phase generator in 1887.<ref>{{cite book | chapter-url=https://ieeexplore.ieee.org/document/4401482 | doi=10.1109/AFRCON.2007.4401482 | chapter=Synchronous generator: Past, present and future | title=Africon 2007 | year=2007 | last1=Hooshyar | first1=H. | last2=Savaghebi | first2=M. | last3=Vahedi | first3=A. | pages=1–7 | isbn=978-1-4244-0986-0 | s2cid=28833835 }}</ref>  In 1888, Ferraris published his research in a paper to the ''Royal Academy of Sciences'' in [[Turin]] and Tesla obtained a United States patent ({{US patent|0381968}}) for his design. Based on the Haselwander generator, [[Mikhail Dolivo-Dobrovolsky]] developed a three-phase generator and motor for the world's first three-phase power plant built in 1891 in Frankfurt, Germany.<ref>[https://edisontechcenter.org/AC-PowerHistory.html AC Power History and Timeline]</ref>