Patent ID: 7378767

Claim:
An AC dynamo electric machine for a motor vehicle, the AC dynamo electric machine comprising: an AC dynamo machine body comprising: a rotor comprised of a first rotatable shaft supported rotatably by a pair of bearings, a rotor core fixedly secured to said first rotatable shaft and a field winding wound on said rotor core, a stator comprised of a stator core disposed in opposition to said rotor and a polyphase stator winding wound on said stator core, and a bracket supporting said pair of bearings and said stator, and a rotational position detector comprising: a second rotatable shaft, a large magnetic reluctance portion through which said second rotatable shaft is coupled to said first rotatable shaft, a second rotor fixedly secured to said second rotatable shaft, and a second stator winding for generating an output voltage based on rotation of said second rotor, wherein said large magnetic reluctance portion comprises a shaft portion which is disposed between said first rotatable shaft and said second rotatable shaft and has a diameter which is smaller than a diameter of said first rotatable shaft and a diameter of said second rotatable shaft, and wherein the large magnetic reluctance portion, the first rotatable shaft and the rotatable shaft constitute a single member.