A slip ring assembly including a plurality conducting disks spaced-apart and stacked mounted along a common rotation axis, each being electrically connectable and fixedly securable to a generator mounted in a rotatable nacelle of a wind turbine so that a rotation of the rotatable nacelle triggers a rotation of the conducting discs; and a plurality of slip ring devices, each being electrically connectable and mechanically securable to a fixed electrical distribution conductor mounted to a fixed pole so as to have a fixed position relative to the fixed pole, and each of the plurality of the slip ring devices having upper and conducting fingers arranged so as to rotatably receive a respective conducting disk therebetween and to provide an electrical connection between the conducting disks and the slip ring device during rotation of the nacelle.

A carbonaceous material is fabricated by kneading of carbon powder and a binder. The carbonaceous material is granulated such that an average particle diameter of the carbonaceous material is 0.3 mm or more. A brush material is fabricated by mixing of the granulated carbonaceous material and metallic powder. A ratio of the metallic powder to a total weight of the brush material is adjusted to 1% by weight or more and 30% by weight or less. Pressure molding is performed on the fabricated brush material, and thermal processing is further performed on the brush material at a temperature at which a resin in the brush material is not carbonized.

A carbonaceous material is fabricated by kneading of carbon powder and a binder. The carbonaceous material is granulated such that an average particle diameter of the carbonaceous material is 0.3 mm or more. A brush material is fabricated by mixing of the granulated carbonaceous material and metallic powder. A ratio of the metallic powder to a total weight of the brush material is adjusted to 1% by weight or more and 30% by weight or less. Pressure molding is performed on the fabricated brush material, and thermal processing is further performed on the brush material at a temperature at which a resin in the brush material is not carbonized.

A DC motor is provided for use in a starter that starts an ermine. The DC motor includes a commutator and a brush. The commutator is formed of copper or a copper alloy whose copper percentage content is higher than or equal to 99 mass %. The brush is arranged in sliding contact with a surface of the commutator. Moreover, the brush is formed of a sintered compact that contains graphite, copper and at least one metal sulfide solid lubricant. The percentage content of copper in the sintered compact is 30-70 mass %. The at least one metal sulfide solid lubricant includes tungsten disulfide. The percentage content of tungsten disulfide in the sintered compact is higher than or equal to 6.5 mass %.

A DC motor is provided for use in a starter that starts an ermine. The DC motor includes a commutator and a brush. The commutator is formed of copper or a copper alloy whose copper percentage content is higher than or equal to 99 mass %. The brush is arranged in sliding contact with a surface of the commutator. Moreover, the brush is formed of a sintered compact that contains graphite, copper and at least one metal sulfide solid lubricant. The percentage content of copper in the sintered compact is 30-70 mass %. The at least one metal sulfide solid lubricant includes tungsten disulfide. The percentage content of tungsten disulfide in the sintered compact is higher than or equal to 6.5 mass %.

A carbon brush unit for a direct current-excited brushed motor may include a carbon brush and a carbon brush holder which is formed to receive the carbon brush. An outer side of the carbon brush and/or an inner side of the carbon brush holder are formed such that in the assembled state of the carbon brush unit defined contact regions and air channels located therebetween result between the outer side of the carbon brush and the inner side of the carbon brush holder in order to dissipate heat, wherein the contact regions are less than 60% of the overall surface of the inner side of the carbon brush holder, wherein the outer side of the carbon brush has a nanostructuring which forms the defined contact regions and air channels.

A carbon brush unit for a direct current-excited brushed motor may include a carbon brush and a carbon brush holder which is formed to receive the carbon brush. An outer side of the carbon brush and/or an inner side of the carbon brush holder are formed such that in the assembled state of the carbon brush unit defined contact regions and air channels located therebetween result between the outer side of the carbon brush and the inner side of the carbon brush holder in order to dissipate heat, wherein the contact regions are less than 60% of the overall surface of the inner side of the carbon brush holder, wherein the outer side of the carbon brush has a nanostructuring which forms the defined contact regions and air channels.

In order to effect a seal a porous material which comprises one side of two opposing surfaces is used to restrict and evenly distribute externally pressurized gas, liquid, steam, etc. between the two surfaces, exerting a force which is opposite the forces from pressure differences or springs trying to close the two faces together and so may create a non-contact seal that is more stable and reliable than hydrodynamic seals currently in use. A non-contact bearing is also disclosed having opposing surfaces with relative motion and one surface issuing higher than ambient pressure through a porous restriction, wherein the porous restriction is part of a monolithic porous body, or a porous layer, attached to lands containing a labyrinth, the porous restriction and lands configured to not distort more than 10% of a gap created from differential pressure between each side of the porous restriction.

A DC motor is provided that can suppress a commutator from wearing. A DC motor including a commutator formed of copper or a copper alloy of 99% or more copper, and a brush pressed against and in contact with the commutator, wherein the brush is composed of a sintered compact including graphite and copper powder, hard compound particles higher in hardness than any of the copper or the copper alloy and the graphite or the copper powder are contained in at least one of the commutator and the brush and are scattered on or near a contact surface of the commutator with the brush at least during use.

A DC motor is provided that can suppress a commutator from wearing. A DC motor including a commutator formed of copper or a copper alloy of 99% or more copper, and a brush pressed against and in contact with the commutator, wherein the brush is composed of a sintered compact including graphite and copper powder, hard compound particles higher in hardness than any of the copper or the copper alloy and the graphite or the copper powder are contained in at least one of the commutator and the brush and are scattered on or near a contact surface of the commutator with the brush at least during use.