PURPOSE: To increase the occupancy ratio of a coil on a core, and improve the space efficiency and cooling effect by shaping the coil at the coil end section, slot coil section, rear coil end section and interconnecting coil section before the coil is wound on the core.

CONSTITUTION: A coil 10 is changed from a previous star shaped one to the one shaped as inserted to a core 3 in advance. When the coil 10 is inserted to the core 3 from its end surface, a slot coil section 12 is located at the same position as the radius of a slot 2 during the insertion of the coil 10. On the other hand, a front coil end section 11 is located inside the inner diameter of the core 3, and, in this condition, inserted to the core 3 over teeth 8 of the core 3. An interconnecting coil 14 is stacked vertically and passes through a slot opening of the core 3. Then, the front coil end section 11 is shaped as outside to the inner diameter of the core 3.