Dynamics of the rigid rotor

Abstract

This chapter on the dynamics of the rigid rotor regards the basic properties of the mechanical plant within the active magnetic bearing loop. It presents methods for its mathematical investigation, and points to characteristics and physical limitations in its behavior. Rotordynamics is a challenging part of machine dynamics. On one hand it refers to classical results of vibration theory and gyro mechanics, and from this point of view it explains terms such as itnatural vibrations, itforward and backward whirl, itcritical speeds, or itnutation and itprecession. On the other hand, in practical rotordynamics there are always questions connected to phenomena which often decisively influence the operation of technical rotors. Such phenomena include process forces in machine tools, for example in milling and grinding machines, electromagnetic forces in electrical drives, interactions of fluid forces with a turbo-rotor, or non-conservative forces in seals and gaps. In these cases AMB can counteract detrimental influences on the rotor dynamics or control them. In addition, AMB with their inherent capability of measuring and influencing rotor states can make a contribution to investigate, explain and identify such phenomena, which are still areas of actual research. © 2009 Springer-Verlag Berlin Heidelberg.