Design of a small, axial-flux permanent-magnet motor

The paper deals with the design of a disc-type motor excited by permanent magnets. The main flux is oriented in the axial direction, yielding a pan-cake type arrangement. The outer diameter is about 45 mm, the axial length about 15 mm. After the introduction, the motor design is explained. On the basis of these general design considerations, the average flux density at no-load in the materials is approximated using an analytical, one-dimensional approach. An accurate analysis of the axial flux machine requires a 3D finite-element calculation. The 3D model design needed for this, is explained The motor characteristics (induced voltage and torque), obtained from the 3D calculation are described and compared with measurements.