Investigation of the Aerodynamic Characteristics of Electric Motors when Regulating Their Speed in the Comsol Package

Abstract

Operation of electric drives of working machines requires knowledge of the influence of the parameters of the cooling system of electric motors on their temperature regime. The widespread introduction of an adjustable electric drive has led to a change in temperature of individual parts of the electric machine. The excess of the insulation temperature with a deep change in the speed of the rotor was especially dangerous. Literature sources draw attention to the difficulties of determining the calculated turbulence coefficients of cooling air flows. In this paper, the images of the air flow distribution are obtained in the Comsol software. In this program, the interfaces of flow movements are provided with the necessary mathematical models for calculating the turbulent regime. A geometric model of a low-power electric motor is formed and the necessary mathematical models for calculating turbulence with the necessary assumptions and restrictions are selected. As a result of the simulation, it was found that the maximum air velocity, at the nominal speed of the rotor, is observed when it exits the protective casing-14 m/s. Analysis of these air flows shows that they have a turbulent character and initially decrease sharply along the ventilation channels to the middle of the machine, and then decrease more slowly. There are also deviations of the maximum air flow velocities from the bed at the end of the ventilation channel. Experimental studies of air velocities in the bed channels confirmed the simulation results with acceptable accuracy. The results obtained can be used for modeling the thermal state in the Comsol program. Also, the results obtained can be used by the operation services of regulated electric drives when working with current frequency converters.