Abstract: A unified mathematical system is suggested for relating the rotor non-linear vibration equation of a low-speed multipolar A. C. motor with the steady-state three-phase nonsymmetric circut equation. The first order approximate solution is obtained. Curves for the amplitude characteristic, the transient process through the zone of resonance, and the process in the starting vibration of the parameter resonance are computed. Experimental research is carried out and results are shown to be in good agreement with the theoretical results, thus revealing the rules of this vibration.

Key words: three-pliaae aaymmetry, transient process, parametric resonance, magnetic field, energy