US Patent 7348691 Magnetic levitation apparatus

A magnetic levitation apparatus supports a magnetic element in a magnetic field. A control system controls a variable magnetic field to maintain the magnetic element at an equilibrium location relative to an unstable axis. In some embodiments the variable magnetic field has a gradient in the direction of the unstable axis but no field component. In some embodiments the magnetic field is provided by an array of four discrete magnets. In some embodiments additional magnets provide increased field intensity at the equilibrium location this increases stability of the levitated magnetic element against overturning. Light and electrical power may be supplied to the levitating magnetic element.