Patent ID: 6154353
Filing Date: 2000-11-28
Classification: F16C

Abstract:
A magnetic suspension system, comprising:a fixed or movable support structure;an electromagnet and a first permanent magnet mounted to said support structure;an object arranged for suspension below said electro-magnet, said object being provided with a second permanent magnet;detector means mounted in a fixed position for detecting a magnet field of said second permanent magnet; and,control means for supplying an electrical current to said electromagnet in accordance with an output signal of said detector means, wherein said control means is normally arranged for supplying current to said electromagnet in a first direction for maintaining said object at a suspended position in which an upwards force on said object, developed by an attractive force between said first permanent magnet and said second permanent magnet, is equal and opposite to the sum of a prevailing downwards force of gravity plus a substantially smaller downwards force, developed by a repulsive force between said electromagnet and said second permanent magnet, said control means being arranged so that when a magnetic field detected by said detector means is above a predetermined limit, a higher current is supplied to said electromagnet in said first direction for developing a greater repulsive force between said electromagnet and said second permanent magnet which creates a net downward force on said object, so as to move said object away from said support structure, said control means further being arranged so that when the magnetic field detected by said detector means is below a predetermined limit, a current is supplied to said electromagnet in a second direction for developing an attractive force between said electromagnet and said second permanent magnet, thereby creating a net upwards force on said object, so as to move said object towards said support structure.