In a magnetic bearing there is no contact between the rotor and the stator; in a one-axis bearing, a passive radial centering is ensured by permanent magnets and the axial stability is obtained thanks to an electromagnet controlled by a servoloop. In a two axis bearing, the axial centering is passive while the radial one is active. An ironless motor/generator using permanent magnets creates the command torques. This technology offers better performance than ball bearings (friction and stiction torques smaller and more stable, no lubrication, no wear). Nevertheless, up to now, the higher mass and price have limited the use of magnetic bearings. But the greater realiability allows the avoidance of a redundant unit and this gives an advantage to the magnetic bearings. Such bearings are used in reaction and momentum wheels for satellite attitude control. Three units will fly on SPOT this year. The growth capabilities of the spin rate without life time reduction makes possible the development of kinetic energy storage systems.
Semi-active magnetic bearings for space application
Halbaktive Magnetlager fuer die Raumfahrt
Second European Space Mechanisms and Tribology Symp. European Space Agency (ESA), Meersburg ; SP-231 , Okt ; 115-120
1985
6 Seiten, 2 Bilder, 4 Tabellen, 5 Quellen
Conference paper
English
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