Mathematical Mechanical Vibration Modeling Stator Winding Inter-Turn Short-Circuit of Mechanical Oscillations of Induction Motor

The article considers the problem of improving the quality of diagnostics of induction motor (IM) in the presence of a stator winding inter-turn short-circuit. During operation of IM, the stator phase windings heat up: briefly — during its start-up, constantly — during engine operation under load. Such overheating of the stator windings over time and with deterioration of the properties of the insulating coatings lead to their partial destruction and, ultimately, to the inter-turn closure of the conductors. To improve the quality of operation of the IM, it is necessary to have reliable diagnostic information about its current technical condition, in particular about changes in vibration parameters and the achievement of their critical values. To do this, it is necessary to conduct research on the influence of electrical and power processes in the IM on vibration parameters during inter-turn circuits. Theoretical and experimental studies have been carried out, a mathematical model of radial forces in the rotor phase winding air gap of an electric motor has been constructed, when stator winding inter-turn short-circuit occurs and develops. Using this mathematical model for the formation of radial forces, calculations were performed for the AIR63V4 electric motor. The estimation of changes in the amplitude and harmonic composition of radial forces at different degrees of development of the inter-turn closure of the stator winding is given. Sufficient vibration diagnostic signs have been identified, in particular, the spectral components of radial vibration characteristic of this defect, which make it possible to determine the presence of this defect and the degree of its danger. The good convergence of theoretical and experimental research results makes it possible to determine the change in diagnostic signs in the entire possible range of defect development. The vibrational signs of this type of defect, described in various literary sources, have been clarified.