This paper describes a preliminary study on a cooling concept for an airborne high performance synchronous motor that has a High Temperature Superconductor (HTS) field winding: whereas the rotor is actually an HTS DC field winding, the armature is an AC copper winding, mounted in an iron-less stator — a so-called “air winding”. The efforts aimed at prototyping a low weight/volume motor lead to a dedicated thermal design where an important role is played by the thermal management of the AC winding, which is the siege of intense power dissipation by Joule and variable magnetic field effects. The analysis reveals thermal constraints that are overlooked by the initial, first stage electromagnetic design and that need to be addressed. The thermal analysis reported here is based on equivalent, lumped thermal circuits: (a) a simplified circuit, aimed at delivering fast, design class results, that may be solved analytically; (b) more complex schemes aimed at assessing variable regimes, which are solved numerically by a circuit simulator. Both approaches are valuable, and complement each other in the quest for a meaningful preliminary design.

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