Patent ID: 7737586

Claim:
A rotating electric machine having a stator and a rotor disposed inside the stator with an air gap defined between them, the rotor having plural coil slots arranged at a predetermined interval in the circumferential direction of the rotor and a field coil of laminated structure fitted in the coil slots, wherein sub slots for serving as cooling fluid ducts in the axial direction of the rotor are provided at the bottoms of the coil slots; radial cooling fluid ducts running in the radial direction of the rotor which communicate the sub slots with the air gap, are provided in the field coil of the rotor and juxtaposed in the axial direction of the rotor; radial cooling fluid ducts are provided in the stator, running in the radial direction of the stator, corresponding in position to the radial cooling fluid ducts provided in the field coil of the rotor, and communicating the inner periphery of the stator with the outer periphery of the stator; the radial cooling fluid ducts in the stator and the radial cooling fluid ducts in the rotor constitute a downward flow path system for guiding the flow of cooling fluid inwardly in the radial direction of the rotating electric machine and an upward flow path system for guiding the flow of cooling fluid outwardly in the radial direction of the rotating electric machine, the downward flow path system and the upward flow path system communicating with each other via the sub slots; and a cooling fluid circulation mechanism is provided to cause the cooling fluid to flow inwardly and outwardly in the radial directions.