ABSTRACT
Turbo generators run up to multiple stages and are interconnected by couplings.In the present paper, additive coupling stiffness (ACS), which is time varying in nature, is used to model the misalignment that exists between bearing centers of two rotor systems integrated with an active magnetic bearing (AMB). While the static stiffness of coupling is ever present, ACS exists only in the presence of misalignment. Presence of misalignment in/about a direction generates harmonics of additive forces and moments in the corresponding direction. These are identified from a linear least-squares problem using amplitude and phase of harmonics from full spectrum of rotor vibration and AMB current.
