PURPOSE: To simplify the structure of a coil and fixing work by a method wherein a part of a coil former is utilized in a molded coil and the coil is supported by and fixed to an iron core.

CONSTITUTION: A coil C consisting of an inside coil 14 and an outside coil 15 is positioned at the outside circumference of an iron core 11. Namely, the inside coil 14 is wound on a coil former combined an iron core 12 through an inside circumferential insulator 13 and a duct piece 16 is positioned on the inside coil 14 to secure a cooling air path and the outside coil 15 is wound on the outside circumference. After applying impregnation treatment to the coil C by epoxy resin or the like, the coil C is heated and hardened to harden in one body and iron plates 12 only at the two faces of the coil former and the coil are formed in one body. The united coil C is fixed at the parts of the inside iron plates 12 on the iron core 11. This eliminates the need for a coil supporter, and the structure and fixing work can be simplified.