Development of Motor Stator with Rectangular Wire Lap Winding and an Automatic Process for its Production

Abstract

A motor stator with a rectangular wire lap winding and an automatic process for its production were developed in order to obtain small high-power motors with excellent efficiency characteristics. The structure of two continuous α-shaped coils and the coil production method involving simultaneous coil forming and coil insertion made mass production of this stator possible. A prototype's slot-fill rate was 80.5%, and the total size of the coil end was 60 to 72mm. On the basis of the ratio between sectional areas of coils, its efficiency was estimated to be higher than those of motor stators with a round wire concentric winding by 3.7% (1000min^-1). In addition, the number of coil parts and the number of welding points were greatly reduced compared to those of a stator with a segmented coil wave winding.