Abstract: A brush holder for dynamo-electric machine has the following parts: a brush making sliding contact with the surface of a rotary collector; a stationary holder part fixed to the stationary part of the dynamo-electric machine opposite to the collector; and a detachable holder part detachably secured to the stationary holder part and holding the brush when separated from the stationary holder part, the detachable holder part being provided with a retainer that clamps the brush when the detachable holder part is separated from the stationary holder part and unclamps the brush when it is attached to the stationary holder part, the brush clamping portion and the portion of the retainer therearound being coated with a coating film of a material having a friction coefficient smaller than the material of the retainer. This arrangement obviates various unfavorable phenomena such as jumping of the brush, sparking on the sliding surface, cracking in the brush and so forth.

Abstract: A slip ring cooling device for electrical rotary machine comprises a plurality of closed chambers axially extending in the peripheral portion with intervals therebetween in the peripheral direction, and an annular passage at one side. The closed chambers each are defined by the surfaces of holes made in the slip ring so as to axially extend at the peripheral portion of the slip ring. The axially extended holes have open ends and closed ends. The annular passage is fluidly connected to each of said open ends so that said closed chambers communicate with said annular passage. A volatile liquid poured in said passage is distributed uniformly to each of said closed chambers by centrifugal force applied thereon upon the rotation of the slip ring. The distributed liquid is evaporated by the slip ring and brushes contacting the slip ring to form vapor. The vapor is transferred to the lower temperature portion by the pressure difference to be cooled and condensed, whereby the slip ring is cooled.

Abstract: A brush holding apparatus for a rotary electric machine permitting removal and replacement of brushes without stopping the rotation of the rotary electric machine comprises a brush holder which can be detached from a stationary unit, and a securing device for detachably securing the brush holder to the stationary unit. A manipulating lever is provided on the stationary unit to actuate the securing device. The brush holder can easily be mounted on or detached from the stationary unit by the manipulation of the manipulating lever for the puppose of removal and replacement of the brushes while the rotary electric machine is in operation.