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.

Provided is a brush wear monitoring arrangement including a carbon brush realized to transfer electric current between a stationary structure and a rotating structure, wherein a side face of the carbon brush is provided with a wear indicator; a brush holder realized to accommodate the carbon brush, which holder is provided with an aperture formed to expose a portion of the wear indicator when the carbon brush is arranged in the holder; and a monitoring means for observing the exposed portion of the wear indicator during usage of the carbon brush. Further provided is a method of monitoring wear on a carbon brush.

Provided is a brush wear monitoring arrangement including a carbon brush realized to transfer electric current between a stationary structure and a rotating structure, wherein a side face of the carbon brush is provided with a wear indicator; a brush holder realized to accommodate the carbon brush, which holder is provided with an aperture formed to expose a portion of the wear indicator when the carbon brush is arranged in the holder; and a monitoring means for observing the exposed portion of the wear indicator during usage of the carbon brush. Further provided is a method of monitoring wear on a carbon brush.

Provided is a brush arrangement of a wind turbine lightning protection system, realized to provide a current path from a hub to a canopy of the wind turbine, which brush arrangement includes a brush holder arranged to hold a brush in electrical contact with a contact surface at the exterior of the canopy, which contact surface is electrically connected to the hub; a bracket arranged to electrically connect the brush with a mounting plate; characterized by an access opening in the front wall of the canopy, which access opening is dimensioned to accommodate the bracket and brush holder; and a mounting arrangement for securing the mounting plate to the canopy front wall over the access opening, from within the canopy interior. A wind turbine including a lightning protection system with at least one such brush arrangement is also provided.

A drive device for a hydraulic pump of a braking system for a motor vehicle includes a housing, a rotor, a rotor shaft mounted in the housing and supporting the rotor, and a commutator arranged in the housing. The commutator includes at least one commutator brush held by a brush holder. The commutator brush cooperates with a commutator ring arranged on the rotor shaft in a non-rotatable manner. The brush holder includes a sealing ring assigned to the commutator which is arranged coaxially to the rotor shaft and interacts with the rotor shaft in a sealing manner.

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.

A system for monitoring the wear state of a carbon brush of a brush holder assembly in which the length of the carbon brush is diminished from an initial length as an end of the carbon brush wears away during use. The system includes a wear state monitor, including a sensor, coupled to the carbon brush. The wear state monitor is configured to rotate as the length of the carbon brush diminishes. The sensor is configured to measure an angular displacement of the wear state monitor as the wear state monitor rotates. The measured angular displacement of the wear state monitor correlates to an amount of diminution in the length of the carbon brush.

A system for monitoring the wear state of a carbon brush of a brush holder assembly in which the length of the carbon brush is diminished from an initial length as an end of the carbon brush wears away during use. The system includes a wear state monitor, including a sensor, coupled to the carbon brush. The wear state monitor is configured to rotate as the length of the carbon brush diminishes. The sensor is configured to measure an angular displacement of the wear state monitor as the wear state monitor rotates. The measured angular displacement of the wear state monitor correlates to an amount of diminution in the length of the carbon brush.

A brush for a motor for electrical equipment in an automobile includes a main brush portion containing carbon and an abrasive having a Vickers hardness higher than or equal to 10 GPa and lower than or equal to 14 GPa. The sliding noise of the brush is reduced in the brush for a motor for electrical equipment in an automobile.