A structurally integrated brushless PM motor for miniature propeller thrusters

This paper is concerned with the design, analysis and performance of a brushless PM motor that is integrated in the structure of a miniature 50 mm diameter propeller thruster. Fitting a relatively large airgap motor with protective coating within the volume of a thin propeller duct (<10 mm thick) imposes extreme constraints on the dimensions of the machine including a very thin rotor and stator radial thickness and relatively short axial length in addition to the relatively large airgap. The paper discusses the design of such a machine, describes a demonstrator device and reports 2D FEA and experimental results.