How is thermal design performed for electrical machines?

Thermal design ensures all parts remain within temperature limits. Methods include: lumped-parameter thermal networks (thermal resistances and capacitances), finite element thermal analysis, and CFD for convection. Key considerations are: heat generation distribution, convection coefficients (dependent on cooling system), contact resistances, material thermal conductivities, and transient thermal capacity. Cooling systems include TEFC, WP-II, liquid cooling (jackets or direct winding), and forced air. Thermal limits determine continuous rating; short-term overload capability depends on thermal time constants.