A new magnetic levitation system with AC magnets

A magnetic levitation system using AC magnets is proposed that has iron rails with primary windings on the ground and levitation magnets with secondary windings placed on the levitated object. A constant AC current is supplied to the primary windings and currents are induced in the secondary windings by magnetic coupling between the primary and secondary windings. The attractive force between the rail and the levitation magnet is controlled by changing the value of the resistance of the secondary winding. By detecting the gap between the magnet and rail and the acceleration of the magnet, the object is stably levitated with feed-back controlling the value of the resistance. In this system, the levitated object has no part contacting the ground and needs no on-board battery. Therefore, this system is very promising as a material transportation system in a clean room. Results proving the feasibility of the system theoretically and experimentally are presented.