Design of PM Brushless Motor Taking into Account Tolerances of Mass Production - Six Sigma Design Method

This paper presents a motor design procedure taking into account tolerances of mass production. The procedure based on combination of analytical and numerical methods, where important inputs parameters could be varied with six sigma distribution. Presented method was used for demanding PM brushless motor design for an electric power steering application. The important factors like: cogging torque, phase resistance, phase inductance, torque speed curve have been calculated and compared with requirements defined in a customer specification. First serial production experience based on a few thousand produced motors confirms selected design procedure.