Estimating Unbalance and Misalignment of a Flexible Rotating Machine from a Single Run-Down

JK Sinha (Bhabha Atomic Research Centre, Mumbai, India), AW Lees (University of Wales Swansea) & MI Friswell (University of Bristol)

Journal of Sound and Vibration, Vol. 272, No. 3-5, May 2004, pp. 967-989


Earlier studies have suggested that the reliable estimation of the state of unbalance (both amplitude and phase) at multiple planes of a flexibly supported rotating machine from measured vibration data is possible using a single machine run-down. This paper proposes a method that can reliably estimate both the rotor unbalance and misalignment from a single machine run-down. This identification assumes that the source of misalignment is at the couplings of the multi-rotor system, and that this will generate constant synchronous forces and moments at the couplings depending upon the extent of the off-set between the two rotors, irrespective of the machine rotating speed. A flexible foundation model is also estimated. The method is demonstrated using experimental data from a machine with two bearings and a flexible coupling to the motor. A sensitivity analysis has also been carried out for the proposed approach with perturbation errors in the rotor and bearing models, to confirm the robustness of the method.

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This material has been published in the Journal of Sound and Vibration, Vol. 272, No. 3-5, May 2004, pp. 967-989, the only definitive repository of the content that has been certified and accepted after peer review. Copyright and all rights therein are retained by the Elsevier.

Link to paper using doi:10.1016/j.jsv.2003.03.006

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