MATHEMATICAL MODELING OF PARAMETERS OF ASYNCHRONOUS MOTORS WITH ELECTRIC DEFECTS OF THE ROTOR
Asynchronous electric motors with a squirrel-cage rotor are the most common class of electric machines in mechanical engineering, transportation, and also in other industries. This is due to the simplicity, high reliability of the design, efficiency and mechanical characteristics. The article deals with the problems of modeling asynchronous electric motors if any rotor defects occur. This is especially important in determining the signs of defects in asynchronous electric motors used in automated production in modern engineering complexes. The stator currents and torque on the motor shaft were chosen as the subject of the simulation. A study has been conducted; the issues of changing the shape of the temporary signal of the stator winding current, its spectral characteristics and the electromagnetic torque depending on the degree of development of rotor bar defects are being examined. The obtained theoretical results show that the development of these defects cause characteristic changes in the shape of the stator windings of the electric motor, their spectral composition and torque on the shaft. The dependence of frequencies that are multiples of the slip frequency on the degree of defect development was revealed. These signs can be used as diagnostic ones for defects in squirrel-cage rotor bars. Since the diagnostic signs of the presence of a defect are related to the slip frequency, diagnostics needs to be performed only under load. The results of mathematical modeling allow us to estimate the effect of defects in the bars of the squirrel-cage of the rotor of the asynchronous electric motor on the mechanical and electrical characteristics at various degrees of their development