Actions for Ambient-temperature passive magnetic bearings [electronic resource] : Theory and design equations

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Ambient-temperature passive magnetic bearings [electronic resource] : Theory and design equations

Published
Washington, D.C. : United States. Dept. of Energy, 1997.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
Physical Description
16 pages : digital, PDF file
Additional Creators
Lawrence Livermore National Laboratory, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information
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Summary
Research has been underway at the Lawrence Livermore National Laboratory to build a theoretical and experimental base for the design of ambient-temperature passive magnetic bearings for a variety of possible applications. in the approach taken the limitations imposed by Earnshaw`s theorem with respect to the stability of passive magnetic bearing systems employing axially symmetric permanent-magnet elements are overcome by employing special combinations of elements, as follows: Levitating and restoring forces are provided by combinations of permanent-magnet-excited elements chosen to provide positive stiffnesses (negative force derivatives) for selected displacements (i.e., those involving translations or angular displacement of the axis of rotation). As dictated by Eamshaw`s theorem, any bearing system thus constructed will be statically unstable for at least one of the remaining possible displacements. Stabilization against this displacement is accomplished by using periodic arrays (`Halbach arrays`) of permanent magnets to induce currents in close-packed inductively loaded circuits, thereby producing negative force derivatives stabilizing the system while in rotation. Disengaging mechanical elements stabilize the system when at rest and when below a low critical speed. The paper discusses theory and equations needed for the design of such systems.
Report Numbers
E 1.99:ucrl-jc--129214
E 1.99: conf-980832--
conf-980832--
ucrl-jc--129214
Subject(s)
Other Subject(s)
Note
Published through SciTech Connect.
12/30/1997.
"ucrl-jc--129214"
" conf-980832--"
"DE98057423"
"YN0100000"
6. international symposium on magnetic bearings, Cambridge, MA (United States), 5-7 Aug 1998.
Post, R.F.; Ryutov, D.D.
Funding Information
W-7405-ENG-48
View MARC record | catkey: 14107498