Thermal Problems in Electrical Machines

Thermal analysis of electric motors is in general regarded as a more challenging area of analysis than electromagnetic analysis in terms of the difficulties in constructing a model and achieving good accuracy. There are only three types of thermal resistance for conduction, convection, and radiation. Thermal network analysis has become the main tool used by many researchers involved in thermal analysis of electrical machines, both for steady‐state and transient analyses. Network analysis is used to calculate conduction through the electromagnetic structure while computational fluid dynamics (CFD) is used for convection at the surface. The thermal network analysis can be sub‐divided into two main calculation types: heat transfer and flow network analysis. This chapter discusses the main characteristics of analytical software packages used in thermal analysis of electrical machines. Finite element analysis (FEA) is now a standard tool for electromagnetic analysis.