A fluid pump includes an electric motor having an armature with a commutator and a motor frame which supports a pair of permanent magnets which are located radially outward from the armature. The motor frame has a support stem extending axially in a direction away from the commutator. A pump section is rotationally coupled to the electric motor and pumps the fluid. First and second motor brushes deliver electricity to the commutator and are urged into electrical contact with the commutator by a first and second springs. The first and second springs are mechanically grounded to a brush spring retainer fixed to the motor frame. The brush spring retainer includes a central portion having an opening within which the support stem is received in an interference fit. A support arm extends from the central portion such that the first and second springs are mechanically grounded to the support arm.

A fluid pump includes an electric motor having an armature with a commutator and a motor frame which supports a pair of permanent magnets which are located radially outward from the armature. The motor frame has a support stem extending axially in a direction away from the commutator. A pump section is rotationally coupled to the electric motor and pumps the fluid. First and second motor brushes deliver electricity to the commutator and are urged into electrical contact with the commutator by a first and second springs. The first and second springs are mechanically grounded to a brush spring retainer fixed to the motor frame. The brush spring retainer includes a central portion having an opening within which the support stem is received in an interference fit. A support arm extends from the central portion such that the first and second springs are mechanically grounded to the support arm.

A fluid pump includes an electric motor having an armature with a commutator and a motor frame which supports a pair of permanent magnets which are located radially outward from the armature. The motor frame has a support stem extending axially in a direction away from the commutator. A pump section is rotationally coupled to the electric motor and pumps the fluid. First and second motor brushes deliver electricity to the commutator and are urged into electrical contact with the commutator by a first and second springs. The first and second springs are mechanically grounded to a brush spring retainer fixed to the motor frame. The brush spring retainer includes a central portion having an opening within which the support stem is received in an interference fit. A support arm extends from the central portion such that the first and second springs are mechanically grounded to the support arm.

A power connection device is provided for transmitting electric power from an external power source to a working machine). The working machine has an undercarriage and a superstructure, and the undercarriage and the superstructure are pivotable relative to each other about a substantially vertical pivot axis. The power connection device includes a first power conductor member which is adapted to be pivotally arranged relative to the undercarriage and the superstructure about the substantially vertical pivot axis.

A power connection device is provided for transmitting electric power from an external power source to a working machine). The working machine has an undercarriage and a superstructure, and the undercarriage and the superstructure are pivotable relative to each other about a substantially vertical pivot axis. The power connection device includes a first power conductor member which is adapted to be pivotally arranged relative to the undercarriage and the superstructure about the substantially vertical pivot axis.

A laminated carbon brush for a liquid pump motor slides in a liquid fuel on a disk-like commutator. The laminated carbon brush includes two layers of a lower resistivity layer and a higher resistivity layer. In both the lower resistivity layer and the higher resistivity layer, circular directional resistivities of the brush along a circular direction in the rotation of the commutator are higher than non-circular directional resistivities of the brush along a radial direction of the commutator and a perpendicular direction to the sliding surface of the commutator. A non-circular directional resistivity of the higher resistivity layer are higher than or equal to 90,000 .Math.cm. No spark discharges occur if the fuel pump motor is operated to output a high power.

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.

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.

The invention relates to a disc commutator and a drum commutator for an electric motor having at least two commutator plates, each having a sliding-surface segment for contacting a carbon brush, said sliding-surface segments being electrically separated from one another. In the disc commutator, the electrical separation extends between the sliding-surface segments towards a commutator diameter inclined at an angle In the drum commutator, the electrical separation of the sliding-surface segments is inclined in the longitudinal direction of the drum commutator and forms an angle with a projection of the rotational axis of the drum commutator on the casing surface of the drum commutator.