Analysis of parametric excited vibrations of drive shafts caused by induction machines

A description of transient phenomena in an induc-tion machine in connection with oscillation excitation in low–damped drive systems requires the solution of a sys-tem of nonlinear differential equations. The coupling of variables from the electrical and mechanical system in the differential equations complicates physical interpretability of the observed phenomena. The paper shows how nonsta-tionary oscillations in the drive shafts, produced by tran-sients in the induction machine, are explained in terms of parametric excitation. The knowledge of the excitation mechanism enables a simple excitation diagram to be con-structed, indicating critical speed ranges for the excitation of oscillations.