Modeling of energy losses in an asynchronous electric motor

Abstract

Special operating conditions of operating electric motors in the agro-industrial sector determine their high accident rate. The rapid introduction of frequency converters leads to the need to analyze the thermal state f electric machines in non-nominal and emergency operating modes and the development of relevant software simulation model of electric drive performance in various operating modes. The thermal computer model developed by the authors and based on the calculation of all losses in an electric machine makes it possible to analyze the aerodynamics of the machine and temperature conditions. As a result of the model implementation, the speeds and directions of air flows in the individual components of the electric motor are established in the Comsol software. It is noted that the air flow velocity changes dramatically from the beginning of the air channel to the end – from 14 m/s to 3 m/s. The multiphysics interface in the software product combines aerodynamic analysis and thermal research. The results of thermal analysis showed that under nominal operating conditions the maximum body temperature was 43 degrees, and the temperature of the stator winding front part was 112 degrees. Studies of the transient process of electric motor start-up showed uneven heating of the front and back parts of the stator winding, the temperature difference was 3 degrees. The obtained computer model will make it possible to establish the influence of losses in the machine, environmental conditions, constructive elements of the electric motor on the temperature of individual components of the research object. Change of operating conditions and regulation of the rotor speed can also be estimated by means of the obtained computer model. Determining a more heated part of the machine makes it possible to properly install the temperature sensors of the emergency protection devices