Editing Nikola Tesla (section)

=== {{anchor|The "Tesla Polyphase System"}}Polyphase system and the Columbian Exposition ===
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[[File:TeslaPOLYPHASEColumbianEXPO1893rwLIPACKownerA.pdf|thumbnail|A Westinghouse display of the "Tesla Polyphase System" at Chicago's 1893 Columbian Exposition]]

By the beginning of 1893, Westinghouse engineer [[Charles F. Scott (engineer)|Charles F. Scott]] and then [[Benjamin G. Lamme]] had made progress on an efficient version of Tesla's induction motor. Lamme found a way to make the [[polyphase system]] it would need compatible with older single-phase AC and DC systems by developing a [[rotary converter]].{{sfn|Carlson|2013|p=166}} Westinghouse Electric now had a way to provide electricity to all potential customers and started branding their polyphase AC system as the "Tesla Polyphase System". They believed that Tesla's patents gave them [[Priority right|patent priority]] over other polyphase AC systems.{{sfn|Carlson|2013|p=167}}

Westinghouse Electric asked Tesla to participate in the 1893 [[World's Columbian Exposition]] in Chicago where the company had a large space in the "Electricity Building" devoted to electrical exhibits. Westinghouse Electric won the bid to light the Exposition with alternating current and it was a key event in the history of AC power, as the company demonstrated to the American public the safety, reliability, and efficiency of an alternating current system that was polyphase and could also supply the other AC and DC exhibits at the fair.<ref>{{cite book |first=Richard |last=Moran |title=Executioner's Current: Thomas Edison, George Westinghouse, and the Invention of the Electric Chair |publisher=Knopf Doubleday Publishing Group |date=2007 |page=222}}</ref><ref>{{cite book |url=https://books.google.com/books?id=-ErxIGp3QN0C |title=America at the Fair: Chicago's 1893 World's Columbian Exposition |first=Chaim M. |last=Rosenberg |publisher=Arcadia Publishing |date=20 February 2008 |isbn=978-0-7385-2521-1 |access-date=3 November 2021 |archive-date=23 March 2024 |archive-url=https://web.archive.org/web/20240323123130/https://books.google.com/books?id=-ErxIGp3QN0C |url-status=live }}</ref><ref>{{cite book|url=https://books.google.com/books?id=F6cWRxU9go4C&pg=PR21|title=The World's Columbian Exposition: A Centennial Bibliographic Guide|first1=David J.|last1=Bertuca|first2=Donald K.|last2=Hartman|first3=Susan M.|last3=Neumeister|year=1996|name-list-style=amp|pages=xxi|publisher=Bloomsbury Academic|isbn=978-0-313-26644-7|access-date=10 September 2012|archive-date=23 March 2024|archive-url=https://web.archive.org/web/20240323123640/https://books.google.com/books?id=F6cWRxU9go4C&pg=PR21|url-status=live}}</ref>

A special exhibit space was set up to display various forms and models of Tesla's induction motor. The rotating magnetic field that drove them was explained through a series of demonstrations including an ''[[Tesla's Egg of Columbus|Egg of Columbus]]'' that used the two-phase coil found in an induction motor to spin a copper egg making it stand on end.<ref>Hugo Gernsback, "Tesla's Egg of Columbus, How Tesla Performed the Feat of Columbus Without Cracking the Egg" Electrical Experimenter, 19 March 1919, p. 774 [http://www.teslacollection.com/tesla_articles/1919/electrical_experimenter/h_gernsback/the_tesla_egg_of_columbus] {{Webarchive|url=https://web.archive.org/web/20200327222415/http://www.teslacollection.com/tesla_articles/1919/electrical_experimenter/h_gernsback/the_tesla_egg_of_columbus|date=27 March 2020}}</ref>

Tesla visited the fair for a week during its six-month run to attend the [[International Electrical Congress]] and put on a series of demonstrations at the Westinghouse exhibit.{{sfn|Seifer|2001|p=120}}<ref>Thomas Commerford Martin, The Inventions, Researches and Writings of Nikola Tesla: With Special Reference to His Work in Polyphase Currents and High Potential Lighting, Electrical Engineer – 1894, Chapter XLII, page 485 [https://archive.org/details/inventionsresear00martiala]</ref> A specially darkened room had been set up where Tesla showed his wireless lighting system, using a demonstration he had previously performed throughout America and Europe;{{sfn|Cheney|2001|p=76}} these included using high-voltage, high-frequency alternating current to light wireless [[gas-discharge lamp]]s.{{sfn|Cheney|2001|p=79}}

An observer noted:

{{blockquote|Within the room were suspended two hard-rubber plates covered with tin foil. These were about fifteen feet apart and served as terminals of the wires leading from the transformers. When the current was turned on, the lamps or tubes, which had no wires connected to them, but lay on a table between the suspended plates, or which might be held in the hand in almost any part of the room, were made luminous. These were the same experiments and the same apparatus shown by Tesla in London about two years previous, "where they produced so much wonder and astonishment".<ref>{{cite book |title=Electricity at the Columbian Exposition; Including an Account of the Exhibits in the Electricity Building, the Power Plant in Machinery Hall |publisher=R. R. Donnelley |last=Barrett |first=John Patrick |year=1894 |pages=[https://archive.org/details/electricityatco00barrgoog/page/n288 268]–269 |url=https://archive.org/details/electricityatco00barrgoog |access-date=29 November 2010}}</ref>}}