Unbalance related rotor precession behavior analysis and modification to the holobalancing method

The precession behavior of an unbalanced rotor–bearing system with anisotropic supporting stiffness is analyzed. The result shows that the probe-orientation-related problem is still unsolved in the holospectrum technique based rotor balancing method. The deficiency of the balancing object of this method now in use, the Initial Phase Vector (IPV), sometimes makes the description or evaluation of rotor balance state unclear. Necessary modification to this method is made in this paper. A compound balancing object comprised of the magnitude of the major axis and the Initial Phase Angle (IPA) of the precession orbit is presented to replace the IPV as the rotor unbalance response. The amount and angular location of the mass unbalance can be determined precisely by the magnitude of the major axis and the IPA, respectively. Since the isotropic assumption is no longer a prerequisite and the evaluation of the mass unbalance amount is independent of the probe orientation, optimal result then can be ensured. The experiment and real application case verify its capability and feasibility.