Analysis of the degree of influence of supply voltage asymmetry on the operational reliability of low-voltage asynchronous electric motors

Abstract

THE PURPOSE. The relevance of research is that the comprehensive substantiation of issues aimed at ensuring the effective functioning of the electrical complex with the presence of an electric motor load in conditions of low-quality supply voltage. The aim of the work is to study the effect of the asymmetry of the supply voltage on the service life of an asynchronous motor with a short-circuited rotor. The main attention is paid to the dynamics of changes in the service life of low-voltage asynchronous electric motors of various series, depending on the level of voltage asymmetry. Asynchronous electric motors of the classic series (4A, AI) and the upgraded (5A, AI’) are identified as the object of research. As is known, the efficient and reliable operation of electric motors is characterized by the service life of the insulation of the windings. A qualitative assessment of the operational reliability of AM is determined by the accuracy of forecasting the real life of their service. That is why, it becomes obvious, the task of an adequate assessment of the operational reliability of low-voltage asynchronous electric motors operating under conditions of low-quality supply voltage directly depends on the complex of studies of such an external influencing factor as the asymmetry of the supply voltage. METHODS. The realization of the research objectives was carried out using the software package "SimPowerSystems" of the interactive programming environment Matlab/Simulink. RESULTS. The research was carried out on asynchronous motors with a short-circuited rotor: classic series (4A132S4, AIR160S8), upgraded series (5A132M6, AIR132S4) with PH = 7,5 kW, rated speed n = 1500 rpm. Modeling of the physical processes of the studied electric motors was carried out by changing the voltage asymmetry coefficient in the reverse sequence (K2U) from 0 to 5% in increments of 1%. Based on the obtained simulation results, diagrams of the change in the service life of AM from the magnitude of the influencing factor are constructed. The studies performed using computer modeling based on the "SimPowerSystems" software package of the Matlab/Simulink system made it possible to predict changes in the service life of AM, estimate the limits of permissible values of the voltage asymmetry coefficient in the reverse sequence, compare the studied electric motors by the level of resistance to an external influencing factor. CONCLUSION. A comprehensive solution to issues related to improving the operational reliability of low-voltage asynchronous electric motors is one of the priority areas, mainly aimed at ensuring the effective functioning of the electrical complex with an electric motor load. In the course of the study, a detailed assessment and analysis of the degree of influence of the asymmetry of the supply voltage on the operational reliability of low-voltage asynchronous electric motors was carried out. The results of the study were discussed, recommendations for the use of asynchronous electric motors in the presence of asymmetry of the supply voltage were formulated.