The Influence of Shaft Surface Error on the Precision of Rotor Dynamic Balancing

During the measurement of shaft vibration displacements of a turbogenerator unit by the use of electric eddy-current sensors of non-contact displacement there exists a surface error component in the measured signals, which results from shaft fabrication errors and shaft surface defects. The direct use of these signals for rotor dynamic balancing will lead to a reduction in the balancing precision, and in extreme cases a failure to effect a balance of the rotor. Based on the specific features of rotor vibration the authors have proposed a vector subtractive method to eliminate the shaft surface error. Through experimental tests it has been verified that the use of the proposed method can dramatically increase the precision of the dynamic balancing.