| 摘要 |
PURPOSE:To reduce a noise without reducing cooling effect by increasing the outer diameter of a fan which is mounted on a rotational shaft that is projected externally from a rotary electric machine body larger than that of a main plate of the fan, and covering it with a fan cover. CONSTITUTION:A rotational shaft 1 of a rotary electric machine body which is sealed by a frame 4 and a bearing bracket 7 is externally projected, an outer fan 9 is engaged with the projection 1', and rotated integrally with the shaft 1. The ratio E/D of the outer diameter D of the fan 9 to the outer diameter E of a main plate 9b of the fan 9 is set to 0.75-0.85, the fan 9 is covered with a fan cover, and air is flowed from a hole 10a in a direction of an arrow 17. The air which is fed out of an outlet 10b is flowed among a plurality of fins 11 which are provided at a frame 4 in parallel with the shaft 1 rightwardly of the drawing to cool the frame 4. Noise can be reduced without losing the cooling effect. |
