THE EVALUATION OF ROTOR IMBALANCE IN FLEXIBLY MOUNTED MACHINES

A method is presented to determine the state of imbalance of 2 rotatin g machine by using the measured pedestal vibration. The only requireme nts of the procedure are a good numerical model for the rotor and an a pproximate model for the bearing behaviour. No assumptions are made co ncerning the operational mode shape of the rotor and the influence of the supporting structure is included in a consistent manner. For simpl icity the analysis is presented in a single plane orthogonal to the ro tor axis, but no difficulty is foreseen in extending the method to two planes. Examples are given for a two-bearing system. (C) 1997 Academi c Press Limited.