A magnetic bearing is usually a bearing which supports a load making use of magnetic levitation. Magnetic bearings support moving machinery without having bodily contact, for instance, they are able to levitate a rotating shaft and allow relative motion with really low friction and no mechanical wear.
They're operating in these industrial applications as electrical power generation, oil refining, machine tool operation and gas pipelines. Also, they are found in the Zippe-type centrifuge utilized for uranium enrichment. Magnetic bearings are employed in turbomolecular pumps where oil-lubricated bearings contain contamination. Magnetic bearings offer the highest speeds of any type of bearing, they've no known maximum relative speed.
It is hard to produce a magnetic bearing using permanent magnets. Therefore, almost all magnetic bearings need constant power input as well as an active control system to keep the load stable. Many bearings are able to use permanent magnets to carry the static load, then exclusively use power once the levitated object varies from the optimum position. Magnetic bearings also traditionally need some type of back-up bearing in the event of power or control system failure and through initial start-up conditions.
Two types of instabilities are quite commonly existing with magnetic bearings. First of all, attractive magnets give an unstable static force which reduces with greater distance and raises at near distances. The second is due to the fact magnetism is often a conventional force, by itself it gives minimum damping, and oscillations could cause loss of successful suspension if any driving forces exist, that they quite typically are.
Magnetic bearing benefits consist of really low and foreseeable friction, capability to operate without lubrication as well as in a vacuum. Magnetic bearings are more and more utilized in industrial machines for example compressors, turbines, pumps, motors and generators. Magnetic bearings are generally utilized in watt-hour meters by electric utilities to calculate home power usage.
Magnetic bearings may also be used in high-precision equipment in order to support equipment in a vacuum, as an example in flywheel energy storage systems. A flywheel in a vacuum has really low windage losses, but traditional bearings usually fail rapidly inside a vacuum resulting from inadequate lubrication. Magnetic bearings also are utilized to support maglev trains to get lower noise and smooth ride by reducing physical contact surfaces.
Disadvantages are including expensive, and comparatively large size.