Aspects of High Performance Flat External Rotor Motors

Flat shaped motors have advantages, in comparison to rod shaped motors, when they are integrated into the limited installation-space in a wide range of applications. In this case motors with windings on iron cores in a slotted stator design are beneficial. The challenge is to design the drives as compact as possible: preserving as much of the feature from bell type armature motors with low cogging torque, and preserving as much performance from slotted motors. This could be implemented in a new motor-series. Key aspects are the design of the magnetic circuit and the winding process on the one hand and improvement of the mechanical design on the other hand. The magnetic flux density could be increased by the use of single sintered segment magnets compared to a commonly used pressed magnetic ring. With the accurate process control of the winding process, wire routing and integrated electrical connection the necessary augmented copperfilling rate could be achieved.