Patent ID: 7554239

Claim:
A dynamo-electric machine comprising: an armature that includes: a rotatable shaft, which is rotatably supported, and a commutator, which is fixed to the rotatable shaft; a brush that is slidably engaged with the commutator at a radially inner end of the brush to energize the armature; an urging means for urging the brush against the commutator; a brush box that has an opening on a commutator side of the brush box and slidably receives the brush, wherein the brush box includes a deformable side wall, which becomes deformable at a predetermined temperature; and a pressing means for pressing the brush against the deformable side wall of the brush box such that a pressing force of the pressing means, which is conducted to the deformable side wall through the brush, causes deformation of the deformable side wall to disengage the radially inner end of the brush from the commutator when the temperature of the deformable side wall reaches the predetermined temperature due to a temperature increase in the brush.