The invention includes a stator disposed inside a yoke, an armature supported inside the stator, a commutator connected to the armature and having a sliding surface in an outer peripheral portion, and a brush disposed opposing the commutator and having a sliding contact surface that comes into sliding contact with the sliding surface of the commutator, wherein the brush has a first member, and a second member with an electrical resistance value higher than that of the first member, the first member is disposed on an entrance side and the second member on an exit side with respect to a direction of rotation of the commutator, and the sliding contact surface of the brush is such that an inclined portion that inclines toward the entrance side with respect to the direction of rotation of the commutator is formed in the first member.

A carbon brush holder is provided, which includes an insulating base, a metal brush frame, and two carbon brushes, wherein the insulating base includes a first base and two second bases correspondingly engaging with two matching portions of the first base respectively; the first base has a first slot having a straight section and two winding sections respectively connected to two ends of the straight section and each of the second bases has a second slot, and a protrusion is formed on a slot wall thereon. The metal brush frame includes a main frame and two branch frames respectively connected to two ends of the main frame, wherein the main frame is embedded in the first slot; the two branch frames are embedded in the two second slots, and are connected to two carbon brushes respectively, to thereby provide an improved contact between the two carbon brushes and a slip ring assembly.

A carbon brush holder is provided, which includes an insulating base, a metal brush frame, and two carbon brushes, wherein the insulating base includes a first base and two second bases correspondingly engaging with two matching portions of the first base respectively; the first base has a first slot having a straight section and two winding sections respectively connected to two ends of the straight section and each of the second bases has a second slot, and a protrusion is formed on a slot wall thereon. The metal brush frame includes a main frame and two branch frames respectively connected to two ends of the main frame, wherein the main frame is embedded in the first slot; the two branch frames are embedded in the two second slots, and are connected to two carbon brushes respectively, to thereby provide an improved contact between the two carbon brushes and a slip ring assembly.

Disclosed herein is a wind turbine rotor which includes a plurality of blades and a hub root, wherein at least one blade is provided with at least one electrostatic noise grounding system. The electrostatic noise grounding system includes an insulated rod having a first end and a second end, a conductive core passing through the insulated rod, a first conductive element connected to the conductive core at the first end of the insulated rod, and a second conductive element competed to the conductive core at the second end of the insulated rod. The electrostatic noise grounding system is secured to a portion of the rotor (e.g., blade bearing housing or blade bearing housing bolted connection) such that the first conductive element is in direct physical contact with at least a portion of the surface of at least one blade and the second conductive element is in direct physical contact with at least a portion of the surface of the hub root.

Disclosed herein is a wind turbine rotor which includes a plurality of blades and a hub root, wherein at least one blade is provided with at least one electrostatic noise grounding system. The electrostatic noise grounding system includes an insulated rod having a first end and a second end, a conductive core passing through the insulated rod, a first conductive element connected to the conductive core at the first end of the insulated rod, and a second conductive element competed to the conductive core at the second end of the insulated rod. The electrostatic noise grounding system is secured to a portion of the rotor (e.g., blade bearing housing or blade bearing housing bolted connection) such that the first conductive element is in direct physical contact with at least a portion of the surface of at least one blade and the second conductive element is in direct physical contact with at least a portion of the surface of the hub root.

An electrical machine (1) with a machine housing (5) receiving an electrically excited rotor (2) and a stator (10) of the electrical machine (1) and with an electronics unit (18) fastened to the machine housing (5) and electrically connected to an exciter winding (3) of the rotor (2) via at least one sliding contact (11, 12) consisting of at least one slip ring (13, 14) assigned to the rotor (2) and at least one brush (15, 16) assigned to the electronics unit (18), the brush (15, 16) being arranged displaceably in a brush holder (20). In this case it is provided that the brush holder (20) is fastened exchangeably in a guiding recess (27) of the electronics unit (18).

An electrical machine (1) with a machine housing (5) receiving an electrically excited rotor (2) and a stator (10) of the electrical machine (1) and with an electronics unit (18) fastened to the machine housing (5) and electrically connected to an exciter winding (3) of the rotor (2) via at least one sliding contact (11, 12) consisting of at least one slip ring (13, 14) assigned to the rotor (2) and at least one brush (15, 16) assigned to the electronics unit (18), the brush (15, 16) being arranged displaceably in a brush holder (20). In this case it is provided that the brush holder (20) is fastened exchangeably in a guiding recess (27) of the electronics unit (18).

The invention relates to a ring electrode for a slip ring for transmitting electrical energy between machine parts, of which at least one machine part can be rotated in relation to another machine part. The ring electrode and corresponding slip ring can be economically produced and have low wear. The electrode is made of a rod material made of stainless steel, which is rolled into a ring and the free ends of the ring are brought together to form a closed ring.

The invention relates to a ring electrode for a slip ring for transmitting electrical energy between machine parts, of which at least one machine part can be rotated in relation to another machine part. The ring electrode and corresponding slip ring can be economically produced and have low wear. The electrode is made of a rod material made of stainless steel, which is rolled into a ring and the free ends of the ring are brought together to form a closed ring.

A carbon grounding brush has a sliding surface that slides on and grounds a driving shaft transmitting driving force and exposed to an insulating liquid. A slit is provided on the sliding surface, and at least one end of the slit is located on one side of the sliding surface. The slit introduces into the slit the insulating liquid pressed towards the sliding surface by the rotation of the driving shaft and discharges the insulating liquid from the one end of the slit. Thus, the contact resistance between the driving shaft and the sliding surface is made small, and electrical corrosion and electromagnetic noises are reduced.