Editing Wireless power transfer (section)

=== Magnetodynamic coupling ===
<!-- "Magnetodynamic coupling" doesn't appear to be fundamentally discernible from resonant inductive coupling. Section is poorly sourced. -->

In this method, power is transmitted between two rotating [[armature (electrical engineering)|armatures]], one in the transmitter and one in the receiver, which rotate synchronously, coupled together by a [[magnetic field]] generated by [[permanent magnet]]s on the armatures.<ref name="Ashley" /> The transmitter armature is turned either by or as the rotor of an [[electric motor]], and its magnetic field exerts [[torque]] on the receiver armature, turning it.  The magnetic field acts like a mechanical coupling between the armatures.<ref name="Ashley" /> The receiver armature produces power to drive the load, either by turning a separate [[electric generator]] or by using the receiver armature itself as the rotor in a generator.

This device has been proposed as an alternative to inductive power transfer for noncontact charging of [[electric vehicle]]s.<ref name="Ashley" /> A rotating armature embedded in a garage floor or curb would turn a receiver armature in the underside of the vehicle to charge its batteries.<ref name="Ashley" /> It is claimed that this technique can transfer power over distances of 10 to 15&nbsp;cm (4 to 6 inches) with high efficiency, over 90%.<ref name="Ashley" /><ref name=Shahan>{{cite web |last1=Shahan |first1=Zach |title=ELIX Wireless Rolls Out A 10kW Wireless EV Charger With 92% Efficiency |url=http://evobsession.com/elix-wireless-rolls-out-a-10kw-wireless-ev-charger-with-92-efficiency/ |website=EVObsession.com |access-date=20 July 2015}}</ref> Also, the low frequency stray magnetic fields produced by the rotating magnets produce less [[electromagnetic interference]] to nearby electronic devices than the high frequency magnetic fields produced by inductive coupling systems.  A prototype system charging electric vehicles has been in operation at [[University of British Columbia]] since 2012.  Other researchers, however, claim that the two energy conversions (electrical to mechanical to electrical again) make the system less efficient than electrical systems like inductive coupling.<ref name="Ashley" />