Permanent magnets brushless DC micro-motors are increasingly used in accurate motion control applications and high precision positioning systems. Main problems concerning their manufacture refer to design accuracy and adequate fabrication technology. The study presented in the paper is based on both numerical analysis and experimental assessment of operating characteristics of such a micro-motor with surface mounted permanent magnets, specially conceived for an application in aerospace technologies. An experimental prototype was manufactured based on inventive design, originally tested and refined by simplified 2D numerical simulation. More realistic 3D models are further developed aiming at the optimization of the motor, according to application specific criteria (high torque, precision in speed control, heating control etc.). The paper presents a 3D reduced model with inclined slots, used in finding an adequate design for the minimization of the cogging torque.

Keywords: Micro-motor, Brushless DC motor, Surface mounted permanent magnets, Finite element method