Abstract: An apparatus for forming a field coil with a low load comprises a rotary table, a reel table to be turned together with the rotary table, six reel bars for guiding and winding a conductor into the coil according to the rotation of the rotary table, and six shaping units disposed alternately with the reel bars. The shaping units are radially movable on the rotary table. A groove-cam-type moving mechanism radially reciprocates, at a rate of one reciprocation per turn of the rotary table, the shaping units on the rotary table with predetermined phase shifts between the movements of the shaping units, thereby pushing the conductor stretched between the reel bars toward the center of the rotary table and shaping the conductor.

Abstract: A coil assembly including a coil of material having a square or hexagonal cross section wound on a bobbin. On the coil winding surface are a plurality of first mutually parallel grooves which have a V-notch cross section and are so arranged that the centers of adjacent grooves are separated from each other by a distance of about P which is the width of said grooves. The coil winding surface also has a plurality of second mutually parallel grooves which have a V-notch cross section and are so arranged that the centers of adjacent grooves are also separated from each other by the distance P. Each of the first grooves is off-set from the corresponding second groove in the axial direction by the distance of about P/2 or less. A pair of intermediate sections with oblique grooves having a predetermined length in the circumferential direction are provided between the respective ends of the first and second grooves.