Permanent-magnet machines with powdered iron cores and prepressed windings

This paper presents a permanent-magnet servo motor, built with a powdered i ron stator, which has been designed to take full advantage of the propertie s of the material. There are a number of important design features which ar e not possible with laminated cores. For example, the core back is axially extended over the end windings, the armature core components are subdivided and preformed stator coils are used. The coils are prepressed to form a so lid component with an exceptionally high fill factor (78%). The prototype o ffers far superior performance to a conventionally laminated commercial mac hine, manufactured in the same frame.