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[[File:Three phase linear induction motor.gif|thumb|A typical 3 phase linear induction motor. An aluminium plate on top often forms the secondary "rotor".]]
{{main|Linear induction motor}}
In this design, the force is produced by a moving linear [[magnetic field]] acting on conductors in the field. Any conductor, be it a loop, a coil or simply a piece of plate metal, that is placed in this field will have [[eddy current]]s [[electromagnetic induction|induced]] in it thus creating an opposing magnetic field, in accordance with [[Lenz's law]].<ref name=Liasi>{{cite journal|last1=Ghaseminejad Liasi|first1=Sahand|title=What are linear motors?|date=15 May 2015|pages=1–50|doi=10.13140/RG.2.2.16250.18887|url=https://www.researchgate.net/publication/
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They have been considered for use as [[weapon]]s, since current [[armour-piercing]] ammunition tends to consist of small rounds with very high [[kinetic energy]], for which just such motors are suitable. Many amusement park [[launched roller coaster]]s now use linear induction motors to propel the train at a high speed, as an alternative to using a [[lift hill]]. The United States Navy is also using linear induction motors in the [[Electromagnetic Aircraft Launch System]] that will replace traditional [[steam catapult]]s on future aircraft carriers. They have also been suggested for use in [[spacecraft propulsion]]. In this context they are usually called [[mass driver]]s. The simplest way to use mass drivers for spacecraft propulsion would be to build a large mass driver that can accelerate cargo up to [[escape velocity]], though [[reusable launch system|RLV]] launch assist like [[StarTram]] to [[low Earth orbit]] has also been investigated.
High-acceleration linear motors are difficult to design for a number of reasons. They require large amounts of [[energy]] in very short periods of time. One rocket launcher design<ref name="coilgun">{{cite web|url=http://www.coilgun.info/theory/electroguns.htm|title=Magnetic Materials - Electromagnetic Guns|publisher=coilgun.info|access-date=2014-11-22}}</ref> calls for 300 GJ for each launch in the space of less than a second. Normal [[electrical generator]]s are not designed for this kind of load, but short-term electrical energy storage methods can be used. [[Capacitors]] are bulky and expensive but can supply large amounts of energy quickly. [[Homopolar generator]]s can be used to convert the kinetic energy of a [[flywheel]] into electric energy very rapidly. High-acceleration linear motors also require very strong magnetic fields; in fact, the magnetic fields are often too strong to permit the use of [[superconductivity|superconductors]]. However, with careful design, this need not be a major problem.<ref>{{Cite journal|journal = Superconductor Science and Technology|year = 2010|title = A single-sided linear synchronous motor with a high temperature superconducting coil as the excitation system|first1 = F. |last1 = Yen|first2 = J. |last2 = Li|first3 = S. J.|last3 = Zheng|first4 = L.|last4 = Liu|first5 = G. T.|last5 = Ma|first6 = J. S.|last6 = Wang|first7 = S. Y.|last7 = Wang|volume = 23| issue=10 |pages = 105015|doi = 10.1088/0953-2048/23/10/105015|arxiv = 1010.4775|bibcode = 2010SuScT..23j5015Y| s2cid=119243251 }}</ref>
Two different basic designs have been invented for high-acceleration linear motors: [[railgun]]s and [[coilgun]]s.
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Linear motors may also be used as an alternative to conventional chain-run lift hills for roller coasters. The coaster [[Maverick (roller coaster)|Maverick]] at Cedar Point uses one such linear motor in place of a chain lift.
A linear motor has been used for accelerating cars for [[crash test]]s.<ref name="google">{{cite
=== Industrial automation ===
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* [[Research Test Vehicle 31]] – A hovercraft-type vehicle guided by a track
* [[Hyperloop]] – a conceptual high-speed transportation system put forward by entrepreneur Elon Musk
* [[Elevator]] {{cite web|url=http://www.thyssenkrupp-elevator.com/Show-article.104.0.html?&L=1&cHash=08b38cb686f00ec874ad82c44c737427&tx_ttnews=546 |title=ThyssenKrupp Elevator: ThyssenKrupp develops the world's first rope-free elevator system to enable the building industry face the challenges of global urbanization
* [[Elevator|Lift]] {{cite web |url=http://www.elevatorworld.com/magazine/synchronous/ |title=Technology: Linear Synchronous Motor Elevators Become a Reality |access-date=2015-06-02 |archive-url=https://web.archive.org/web/20150330081619/http://www.elevatorworld.com/magazine/synchronous/ |archive-date=2015-03-30 |url-status=dead }}
*[[Magway Ltd|Magway]] - a UK freight delivery system under research and development that aims to deliver goods in pods via 90 cm diameter pipework under and over ground.
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