Abstract <p>Analysis of the thermal state of an electric machine at the design stage is an integral part of any project. When creating large high-load generators, reliable information about the temperature field of the machine serves as the basis for ensuring its reliable and long-term operation. Determining the maximum temperatures of such elements as winding insulation and permanent magnets that are most sensitive to overheating is a task that includes determining the power of heat sources, parameters of the heat removal scheme, calculating the ventilation system, etc. A combined approach to the design and analysis of the cooling system of a low-speed direct-drive wind turbine is presented, consisting in the sequential solution of several problems: calculating losses in active parts, numerical 2D modeling of the thermal field with the definition of the most effective ventilation and heat-removal system, and refined 3D thermal calculation of the inverse problem for determining the parameters of blowing the cooling medium through the hydraulic tract.</p>