Patent ID: 6097115
Filing Date: 2000-08-01
Classification: H02K

Abstract:
A method of tuning a rotor to reduce unwanted noise and vibration from a motor, said method comprising the steps of:(a) selecting a first motor comprising a first shaft, a first set of at least one bearing supporting said first shaft, a first plurality of laminations stacked axially along a first length of said first shaft, and a first stator, wherein said first shaft, first set of at least one bearing, and first plurality of laminations comprise a first shaft system having a first natural frequency, and said first plurality of laminations engage said first shaft over a first length, not necessarily continuous, of said first shaft;(b) measuring said first natural frequency;(c) selecting an increment to said first natural frequency;(d) constructing a second motor comprising a second shaft, a second set of at least one bearing supporting said second shaft, a second plurality of laminations stacked axially along a second length of said second shaft, and a second stator, wherein said second motor and said first motor have like dimensions and numbers of bearings, except that said second plurality of laminations engage said second shaft over a selected second length, not necessarily continuous, of said second shaft, and wherein said selected second length is shorter than said first length if said increment is negative, and is longer if said increment is positive.