Abstract: Slotless and toothless wound stators are produced for electrical machines, in particular brushless DC motors, by providing temporary teeth at opposite ends of an iron cylinder with smooth inner wall end-to-end, placing an electrical winding without supporting form against the inner wall and between and around the teeth, pressing the winding against the smooth inner wall by an expandable retaining cylinder, and removing the temporary teeth. A temporary fixture can provide the temporary teeth by radially inwardly extendable and radially outwardly retractable fingers, the fingers being removed by outward retraction through cam means. Alternately, plastic end members with teeth may be glued to opposite ends of the smooth-walled iron cylinder to provide temporary teeth, the teeth being machined off after positioning the winding.

Abstract: A coil unit for use in brushless and ironless armature motors which includes the form upon which the same is wound and providing, in its complete form, a self supporting coil unit which may be inserted into the laminations or soft iron shell of a motor.The complete coil unit includes a plurality of individual coils which are arranged in skewed, longitudinal, side-by-side relation to one another and the individual windings of the coils are positioned on both the inner and outer surfaces of the coil form, the inner and outer windings pairs being diametrically opposed to one another to thereby provide a pair of diametrically opposed coil portions which are connected in series aiding fashion.The coil form is a thin, longitudinally extending, tubular member of a non-magnetic material providing coil winding and locating cutouts or serrations on the longitudinal ends thereof.