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Title: Dynamically stable magnetic suspension/bearing system

A magnetic bearing system contains magnetic subsystems which act together to support a rotating element in a state of dynamic equilibrium. However, owing to the limitations imposed by Earnshaw's Theorem, the magnetic bearing systems to be described do not possess a stable equilibrium at zero rotational speed. Therefore, mechanical stabilizers are provided, in each case, to hold the suspended system in equilibrium until its speed has exceeded a low critical speed where dynamic effects take over, permitting the achievement of a stable equilibrium for the rotating object. A state of stable equilibrium is achieved above a critical speed by use of a collection of passive elements using permanent magnets to provide their magnetomotive excitation. The magnetic forces exerted by these elements, when taken together, levitate the rotating object in equilibrium against external forces, such as the force of gravity or forces arising from accelerations. At the same time, this equilibrium is made stable against displacements of the rotating object from its equilibrium position by using combinations of elements that possess force derivatives of such magnitudes and signs that they can satisfy the conditions required for a rotating body to be stably supported by a magnetic bearing system over a finitemore » range of those displacements.« less
Inventors:
 [1]
  1. (Walnut Creek, CA)
Issue Date:
OSTI Identifier:
870322
Assignee:
Regents of University of California (Oakland, CA) LLNL
Patent Number(s):
US 5495221
Contract Number:
W-7405-ENG-48
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Country of Publication:
United States
Language:
English
Subject:
dynamically; stable; magnetic; suspension; bearing; contains; subsystems; support; rotating; element; dynamic; equilibrium; limitations; imposed; earnshaw; theorem; systems; described; possess; zero; rotational; speed; mechanical; stabilizers; provided; hold; suspended; exceeded; critical; effects; permitting; achievement; achieved; collection; passive; elements; permanent; magnets; provide; magnetomotive; excitation; forces; exerted; levitate; external; force; gravity; arising; accelerations; time; displacements; position; combinations; derivatives; magnitudes; signs; satisfy; conditions; required; stably; supported; finite; range; magnetic force; magnetic forces; stable equilibrium; magnetic bearing; rotational speed; permanent magnet; permanent magnets; bearing systems; passive elements; rotating element; stable magnetic; forces exerted; forces arising; external forces; conditions required; dynamic effects; dynamic equilibrium; dynamically stable; magnetic subsystems; magnetic suspension; contains magnetic; /335/310/