Abstract: The vibration of machine set is seldom caused by single fault. The compound effect of ubiquitous asymmetric stiffness and multi-fault makes rotors precess in a complicated form. The estimation of unbalance mass then can be disturbed by these factors and the field balancing operation will be ineffective. An improved holo-balancing method with the initial phase vector of forward precession component as the correction object is presented through the decomposition of synchronous precession orbit. Since the disturbance of backward precession component is eliminated, the balancing is more effective than those traditional methods. Furthermore, studies on the trend of rotor precession parameter during the balancing procedure are carried out and a stoppage criterion of field balancing operation is set to eliminate blindness. Two experiments are carried out and the effectiveness of the analytical result is verified.

Key words: Fault, Field balancing, Holospectrum, Initial phase vector, Precession radius ratio, Rotor