Patent ID: 7592732

Claim:
An armature winding of a rotary electro-dynamic machine in which plural strand conductors which pile up respectively are stored in respective winding slot of a stator core comprising plural ventilating ducts in the radial direction and plural winding slot in the axial direction, the strand conductors being formed so as to be twisted and transposed continuously toward the extending direction of the winding slot at a portion stored in the winding slot, plural transposition pitches of the strand conductors being provided so as to minimize the unbalanced voltage in the strand conductors, and the strand conductors being short-circuited at the ends of the armature winding which protrude outward from the sides of the stator core, wherein sub core sections whose space factors in the stator coil are different are arranged in part of the stator core, and an inflexion point of the transposition pitch of the strand conductors is shifted from the position to minimize the unbalanced voltage in the strand conductors caused by magnetic fluxes crossing in the strand conductors in the core or between the strand conductors in the core and the strand conductors at the end portions of the core when the stator space factor is uniform in the stator core, so as to offset the unbalanced voltage occurring in the strand conductors due to the magnetic reluctance of the stator core, the magnetic reluctance being varied by the sub core section.