Influence of electromagnetic Field Damping on the Vibration Stability of soft mounted Induction Motors with Sleeve Bearings, based on a Multibody Model

Abstract

The paper shows an analytical vibration model for stability analysis of soft mounted induction motors with sleeve bearings, especially focusing on the influence of electromagnetic field damping on the limit of  vibration stability. The model is a multibody model, considering the electromagnetic influence – including the electromagnetic field damping effect –, stiffness and internal material damping of the rotor structure, stiffness and damping of the bearing housings and end shields, stiffness and damping of the foundation elements and stiffness and damping of the oil film of the sleeve bearings. The aim of the paper is to unite all these influences in a model and to derive a procedure for calculating the limit of vibration stability, with considering the electromagnetic field damping effect. Additionally, a numerical example is presented, where the influence of electromagnetic field damping on the limit of vibration stability is shown, as well as the influence of the foundation elements and of the internal damping of the rotor. The procedure and  conclusions can also be adopted into finite-element analysis.