Mathematical model of heating an asynchronous motor with a squirrel-cage rotor based on an equivalent thermal circuit

The largest share of failures of asynchronous motors in industry is associated with overheating of the stator winding insulation as a result of improper operation of the equipment. In this paper, methods of mathematical modeling of thermal processes of an asynchronous motor with a squirrel-cage rotor are applied to assess the thermal state of the elements of the electric motor design. The simulation is based on the method of equivalent thermal circuits for stationary heating. The mathematical model consisting of 10 main units of the electric machine is taken as a basis. The aim of the paper is to experimentally test the adequacy of the proposed mathematical model and evaluate the possibility of its application for diagnosing the state of the electric motor by measuring the stator current without using built-in sensors. The simulation results were verified experimentally using thermal imaging equipment. Based on the results of comparing the mathematical model and experimental data, it was concluded that the proposed model can be used to study the thermal regimes of an asynchronous motor with a squirrel-cage rotor.