Impact Excitation Tests to Determine the Influence Coefficients for Balancing Lightly Damped Rotors

Experiments have been conducted to evaluate a supplementary method for balancing lightly damped rotors. The rotor, while running, is excited by an impact generator, and the response is measured at the bearings by transducers for displacement, force, and acceleration. An FFT analyzer is employed to obtain the frequency-dependent transfer functions from which the corresponding influence coefficients can be calculated. The results are compared with the values obtained from the conventional trial weight method, and they are also used in a successful balancing of the rotor.