Armature coil and method of manufacturing the same

An armature coil in which a plurality of slots through which coil conductors pass are annularly arranged and a plurality of said coil conductors pass through the inside of said slot in line,

• wherein, the circumferential width of the plurality of said coil conductors is formed in a substantially trapezoidal shape which gets narrower toward the radially inner side and the cross-sectional areas of the plurality of said coil conductors in said slot are each substantially the same and the circumferential width thereof is formed narrower as said coil conductor is arranged toward the radially inner side;
• and
• a coil conductor is formed in a convex shape on a surface abutting another coil conductor and the another coil conductor is formed in a concave shape on a surface abutting the convex shaped surface on the coil conductor,
• wherein a cross-sectional shape of the plurality of coil conductors is symmetrical, wherein the number of said coil conductors is three or more, each having a convex shape, and the convex shape has a larger amount of protrusion of the convex shape on coil conductors on the radially inner side as compared to coil conductors on the radially outer side.