Abstract: A method of making a rotor, for a dynamo-electric machine, which has a number of arcuately formed rectangular loop coils arranged edgewise in a cylindrical configuration, employs injection moulding. Moulding material is injected between adjacent coils and penetrates between and around them to form an encapsulating framework. Entry of moulding material into the central apertures of the coils is prevented by inserts. By directing the moulding material inwardly, and spacing the coils slightly from the mould core, encapsulant also penetrates behind the coil faces to form a thin skin. By use of a shutter member, which may be an integral end cap, coil terminations can be led out of the mould cavity through apertures in the shutter to protect them from damage during the moulding process.

Abstract: An electric rotary actuator for producing rotation through a limited angle comprises a rotor winding made of a plurality of thin loop coils arranged in a continuous cylindrical framework as part of a rotor shell. The rotor shell lies in an annular flux gap defined by a stator magnet assembly and a flux return means. Each pair of adjacent axially extending limbs of adjacent loop coils lies opposite to and cooperates with a respective stator pole face. This winding arrangement helps to optimize the torsional resonance characteristics of the rotating mass.