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US 9,197,110 B2Granted
Electrostatic stabilizer for a passive magnetic bearing system
AssigneeLawrence Livermore National Security, LLC
InventorRichard F Post
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Abstract
Electrostatic stabilizers are provided for passive bearing systems composed of annular magnets having a net positive stiffness against radial displacements and that have a negative stiffness for vertical displacements, resulting in a vertical instability. Further embodiments are shown of a radial electrostatic stabilizer geometry (using circuitry similar to that employed in the vertical stabilizer). This version is suitable for stabilizing radial (lateral) displacements of a rotor that is levitated by annular permanent magnets that are stable against vertical displacements but are unstable against radial displacements.
Claims18
An apparatus, comprising:
- a right cylindrical rotor rotatable about a central longitudinal axis, wherein said rotor comprises a first rotor surface comprising metal and a second rotor surface comprising metal, wherein said first rotor surface and said second rotor surface are located at opposite ends of said rotor;
- a first pair of concentric electrodes, comprising a first electrode and a second electrode, wherein said first electrode and said second electrode are spaced from each other and are spaced by a first gap from said first rotor surface;
- a second pair of concentric electrodes, comprising a third electrode and a fourth electrode, wherein said third electrode and said fourth electrode are spaced from each other and are spaced by a second gap from said second rotor surface;
- at least one source of radio frequency (RF) voltage connected across said first electrode and said second electrode to form a first series circuit, wherein said at least one source of RF voltage is connected across said third electrode and said fourth electrode to form a second series circuit;
- at least one inductor in said first series circuit;
- at least one inductor in said second series circuit;
- and
- a passive magnetic bearing system configured to provide radial and tilt stabilization of said rotor with respect to said central longitudinal axis upon rotation of said rotor.
5 more elements
A method comprising:
- providing apparatus, comprising:
- a right cylindrical rotor rotatable about a central longitudinal axis, wherein said rotor comprises a first rotor surface comprising metal and a second rotor surface comprising metal, wherein said first rotor surface and said second rotor surface are located at opposite ends of said rotor;
- a first pair of concentric electrodes, comprising a first electrode and a second electrode, wherein said first electrode and said second electrode are spaced from each other and are spaced by a first gap from said first rotor surface;
- a second pair of concentric electrodes, comprising a third electrode and a fourth electrode, wherein said third electrode and said fourth electrode are spaced from each other and are spaced by a second gap from said second rotor surface;
- at least one source of radio frequency (RF) voltage connected across said first electrode and said second electrode to form a first series circuit, wherein said at least one source of RF voltage is connected across said third electrode and said fourth electrode to form a second series circuit;
- a passive magnetic bearing system configured to provide radial and tilt stabilization of said rotor with respect to said central longitudinal axis upon rotation of said rotor,
- at least one inductor in said first series circuit, wherein said at least one inductor in said first series circuit is configured to produce a first resonant frequency in said first series circuit;
- at least one inductor in said second series circuit, wherein said at least one inductor in said second series circuit is configured to produce a second resonant frequency in said second series circuit;
- rotating said rotor;
- and
- providing said RF voltage at an RF frequency to said first series circuit and said second series circuit, wherein said RF frequency is higher than said first resonant frequency and said second resonant frequency.
8 more elements
Dependencies are inferred from the claim text.