Patent ID: 7589449

Claim:
An electric rotating machine including an armature formed by winding an armature winding on an armature core, and a rotor rotatably supported on the inner diameter side of said armature with a predetermined space; said rotor including a rotor core comprising a cylindrical part on the other periphery of which a field winding is wound, and a claw-pole shaped magnetic pole part that is magnetized so that magnetic claw poles adjacent each other in circumferential direction are different in polarity; and a permanent magnet for supplying magnetic flux to said armature core in cooperation with said field winding is disposed in said claw-pole shaped magnetic pole part, wherein a magnetic short-circuit mechanism is disposed between the magnetic claw poles adjacent each other in circumferential direction of said rotor core; and said magnetic short-circuit mechanism causes a magnetic plate composed of a material of high magnetic permeability to move toward radial direction of said rotor core so as to short circuit between N-pole and S-pole of said permanent magnet due to centrifugal force acting in accordance with rotation of said rotor, and wherein said magnetic short-circuit mechanism has a non-magnetic case in which said permanent magnet, said magnetic plate, and a coil spring expanding and contracting so that the magnetic plate comes in contact with or separates from the permanent magnet, are accommodated.