Damping ratio estimation of Three-Phase Induction Motor

Three-Phase Induction Motors are both electrical and mechanical structures. In this paper an analysis from mechanical point of view is done. The modal parameters, natural frequencies, modal shapes, damping ratio, modal masses describe in the whole the modal behaviour of a mechanical structure. For a better design in dynamic analysis and a decreasing the vibration and noise levels it is necessary to be known the damping ratio. This internal modal parameter can be found only by experimental data. The present paper describes a possible solution of defining mathematical functions of damping ratio vs. frequencies based on experimental modal analysis.