PURPOSE: To reduce the deviations of heat sinking capabilities distributed in the directions of the heights of the cooling fins of a fancooled rotating machine, by forming obliquely in the axial direction of the machine the bottom parts of the ventilaion paths of cooling winds which are laid between the adjacent cooling fins, in the rotating machine wherein the cooling fins extended in the axial direction of the machine are provided on the outer periphery of a stator frame made of casting in a plurality of rows.

CONSTITUTION: A totally-enclosed fancooled rotating machine has a stator frame 3 on whose inner peripheral side a stator core 2 wound by a stator coil is provided. The stator frame 3 made of casting has on its outer periphery in a body a number of cooling fins 11, 12 extended in the axial direction of the machine which are laid along the circumference of the frame in a plurality of rows. In this case, tapers 13a, 14a in the axial direction of the machine which are formed in the heights of the bottom parts of outside-air-cooled ventilation paths 13, 14 surrounded by the adjacent cooling fins 11, 12 are so formed respectively that their inclinations are opposed to each other. Thereby, the locations of the nucleuses of the speeds of outside-air-cooled winds are distributed over wide ranges in the directions of the heights of the cooling fins 11, 12. As a result, the deviations of heat sinking capabilities distributed in the directions of the heights of the cooling fins are reduced, and the heat sinking capabilities in the places neighboring the roots of the cooling fins which are present on the opposite side to an outside fan are improved.