Towards the Forming of concentrated Windings with trapezoidal Cross Sections for Increasing the Slot Filling Factor

Abstract

The steadily growing use of industrial electric motors worldwide, combined with the need for improved efficiency, require advanced technologies that are beneficial with regard to resource efficiency and productivity. One possibility for saving raw materials is to reduce the size and weight of motors while maintaining the same performance. This can be achieved through an increase of the so-called slot filling factor, which has substantial influence on the torque generation in the electric machine. One way of increasing the slot filling factor is to shape the respective conductors in such a way that the cross sections correspond to their position. The focus of this paper lies on the description of interactions in the forming process of tooth coils with trapezoidal cross section geometry of the individual turns. In particular, the shaping of the coil heads of coils produced by sequential forming and subsequent bending is characterized via FEM forming simulation. Furthermore, the contribution presents a possibility for manufacturing coils of different geometries at high output rate by using flexible forming operations. Compared to manufacturing process chains suggested earlier, this approach allows considerable shortening and optimization of the process chain.