Theoretical aspects of developing thermodynamic models of electric motors

The paper provides a generalized mathematical description of the thermodynamic model for an electrical machine, which is based on thermal circuits for any number of nodes and cooling media. This description considers an influence of temperature of nodes on the thermal losses at these nodes. Considering the dependence of power losses in the nodes of the thermodynamic model on the temperature of these nodes due to temperature dependency of winding resistance does not change the model linearity. The analysis proves that if there is no dependence of the power losses in the nodes of the thermodynamic model on the temperature of these nodes, in-time change of transient components of thermodynamic processes of this model is always of an acyclic damped nature. However, if there is a temperature dependence of the power losses, this provision is not always relevant. The authors have analytically defined the conditions of non-limited temperature rise of electric machine components without switch to steady-state mode (provided there is a temperature dependence of the power losses).