A steel ball bearing is suspended in air by an actively controlled
electromagnet.
Movies of the MagLev in action
The device shown above is an actively controlled magnetic
levitator. Magnetic levitation is a technique widely used to create
noncontact bearings. Such bearings eliminate friction and wear and
also allow for operation at high speeds or in special environments such
as vaccum systems. Maglev trains are perhaps the most visible application
of the technology, their freedom from wheels making them capable of reaching
speeds of over 350 mph.
This site looks at a levitator that is both a classroom-level demonstration
of the principles involved in a maglev system and an experimental implementation
of control mechanism for magnetic levitators. The system is first
examined, then emphasis is placed on the methods by which such a system
can be controlled and the hardware which can be used to implement such control.