A model-based prediction of balancing behavior of rotors above the speed range in available balancing systems

Rotor balancing is probably the most discussed topic in the entire literature about rotor dynamics. It would therefore seem that, from the point of view of theory, this is a problem of little interest, however, balancing is very relevant in the industrial practice and sometimes there are very particular cases that cannot be addressed and solved by traditional methods. Moreover, many papers deal with only simulated results or with small-scale tests-rigs, which can hardly reproduce the behavior of real rotors. The case described in this paper is just one of these and presents what could be defined as “predicting the effect of balancing” at rotational speeds that are higher than those possible on balancing machines. Rotordynamics modeling, identification techniques developed by the authors and the available vibration measurements allow the simulation of the behavior, i.e. the vibrations, of the considered turbine rotor on the balancing machine, even at rotational speeds higher than those are possible to be reached, but that correspond to the trip speed in the plant.