Device for cooling the collector portion of a rotary electric machine

Claim 1

A cooling device for the collector ring and brush arrangement mounted on the rotor shaft of rotary electric machines comprising ventilation means mounted on said rotor shaft in the vicinity of one end of said collector ring and brush arrangement for sucking in cooling air through the collector ring and brush arrangement, a fan guide in the form of an annular housing located between said ventilation means and one end of said collector ring and brush arrangement for defining the flow paths of cooling air sucked in by said ventilation means with respect to said collector ring and brush arrangement, said fan guide being in a plane transverse to the axis of and extending around said ventilation means on said rotor shaft and being provided with an opening portion adjacent to the surface of the collector ring to permit the cooling air to flow in paths along the surface of the collector ring, and a plurality of balancing ventilation holes provided in said fan guide in a number at least equal to the number of brush arrays and being located axially with respect to the rotor shaft at a height from the rotor shaft corresponding to thE brush outer periphery so that part of the cooling air is permitted to flow in a path along the outer surface of the brushes into said plurality of balancing ventilation holes in the direction of the axis of said rotor shaft, thereby controlling the flow of the cooling air in the vicinity of the heads of the brushes to direct it in substantially the same radial direction as that in which the brushes are normally compressed against the collector ring.