Patent ID: 6579078
Filing Date: 2003-06-17
Classification: F04D,F05D,F16C,H02K

Abstract:
A multi-stage centrifugal compressor with an integral high-speed motor for compressing air comprising:a) a variable speed permanent magnet motor having electronically commutated stator coils surrounding a rotor carrying permanent magnets, wherein there is a gap between the coils and the rotor, said rotor having a magnetic steel rotor shaft rotatably supported at each end by pressurized oil lubricated hydrodynamic bearings, wherein the stator coils are comprised of a plurality of stator wires extending longitudinally along the stator and continuing around the ends of the stator to define end turns; b) a plurality of compressor impellers mounted to turn with the rotor shaft, c) a pump for introducing cooled oil into the bearings for lubricating the bearings and for cooling the bearings, rotor and stator coils, said bearing configured so that oil exiting from the bearings splashes over the supported ends of the shaft and splashes over the end turns of the stator coils, and d) passageway through the stator for introducing pressurized air during start up to maintain a positive pressure within the gap thereby displacing oil from the gap.