Air-cooled, high torque machines for aerospace applications

With the increased electrification of aircraft, the use of motors to replace traditionally mechanical or hydraulic auxiliary systems has increased. Aerospace motor design has the rather unique characteristics of mass and torque density being extremely important, whereas cost is less so. For low maintenance, non-safety critical components, which are only used for short durations of the flight cycle, efficiency also becomes less important, whilst eliminating an external cooling circuit and gearbox can look very attractive. In order to meet a stringent mass target, this paper considers two high torque density machines suitable for low speed applications. As mass is reduced, thermal capability becomes critical and thermal simulations are presented for operational characteristics.