Abstract: In view of the disadvantages of steady-state balancing techniques, a novel double-plane balancing method of flexible rotor is proposed, in which the run-up transient amplitudes are utilized. Based on the three-circle balancing method(i.e. single-plane balancing without phase measurements), the modal ratio among measurement points(MRMP coefficient) is introduced, and the MRMP coefficients among the two balancing planes are calculated by using the transient amplitudes during the rotor runs across its first two resonant regions, thus the trial weight group can be decomposed into its first and second modal components. Then, through 3 run-up processes, the three-circle balancing method is used to correct the first and second modal unbalances respectively, by using the corresponding resonant amplitudes and the corresponding trial weight component. Both the simulation and experiment results show that the proposed balancing method not only can reduce the transient residual vibrations effectively, but also avoid the requirement of prior rotor modal knowledge which is necessary for the traditional steady-state modal balancing method.

Key words: Modal balancing, Rotor balancing, Run-up process, Transient response, Rotor