The invention relates to a commutator, comprising an insulating base and a plurality of commutator segments arranged on the insulating base, wherein each commutator segment comprises a metal layer, a transition layer and a graphite layer arranged on the base in sequence. The transition layer contains a material identical to that of the graphite layer and a material identical to that of the metal layer. The invention further relates to a motor comprising the commutator and a method for manufacturing the commutator. As the transition layer contains the material identical to that of the graphite layer and the metal layer, the problem that the graphite layer and the metal layer are cracked during high temperature sintering is resolved. The service life of the commutator is prolonged. The method for manufacturing the commutator reduces chemical contamination and production cost caused by electroplating and brazing used in a traditional technology.

The invention relates to a commutator, comprising an insulating base and a plurality of commutator segments arranged on the insulating base, wherein each commutator segment comprises a metal layer, a transition layer and a graphite layer arranged on the base in sequence. The transition layer contains a material identical to that of the graphite layer and a material identical to that of the metal layer. The invention further relates to a motor comprising the commutator and a method for manufacturing the commutator. As the transition layer contains the material identical to that of the graphite layer and the metal layer, the problem that the graphite layer and the metal layer are cracked during high temperature sintering is resolved. The service life of the commutator is prolonged. The method for manufacturing the commutator reduces chemical contamination and production cost caused by electroplating and brazing used in a traditional technology.

The invention relates to a disk blank (18) for producing commutator bars of a disk commutator as well as to a commutator bar and a disk commutator realized as having such commutator bars, said disk blank (18) being realized as a multi-layered body and having a carbon mold body having a continuous first layer and having a contact arrangement which forms a second layer disrupted by transition areas in such a manner that the transition areas do not comprise any contact material.

An electrical machine with a brush commutator arrangement (1) is proposed. Brushes (3) and a commutator (5) are adapted and arranged such that, upon operating the electrical machine (1), the brush (3) and the commutator (5) are displaced relative to each other in a lateral displacement direction (7) and a contact surface (9) of the brush (3) mechanically contacts a contact surface (11) of the commutator (5) along an overlapping area (13) thereby generating an electrical contact. Accordingly, an electric current is transmitted between brush (3) and commutator (5) through the overlapping area (13). An orthogonal electrical conductivity of the brush (3) and/or the commutator (5) in a direction (25) orthogonal to a respective contact surface (9, 11) locally varies along the lateral displacement direction (7). An orthogonal electrical conductivity distribution in the brush (3) and/or the commutator (5) is adapted such that, even when operating the electrical machine at maximum allowable power, for at least 90% of all spatial configurations during displacing the brush (3) and the commutator (5) relative to each other, an electrical current density through the overlapping area (13) does not exceed 130% of a rated maximal average electrical current density through the brush commutator arrangement (1). Due to the specific variation of orthogonal electrical conductivity within the brush (3) or commutator (5), sparking and resulting wear in the proposed brush commutator arrangement (1) may be reduced.

The invention relates to the use of a carbon composite material for manufacturing electrical contact elements of a fuel pump operated in a fuel environment, the contact elements being designed as carbon molds, wherein, in addition to carbon, the carbon composite material comprises a thermosetting or thermoplastic binder and a metal content that amounts to more than 0.5% and less than 25% of the total mass of the carbon composite material.