An electrical contact device includes a high electric potential-side contact and a low electric potential-side contact having a lower electric potential than the high electric potential-side contact. The high electric potential-side contact and the low electric potential-side contact are configured to be brought into and out of contact with each other. At least one of the high electric potential-side contact and the low electric potential-side contact is formed of a low-boiling point material whose boiling point is lower than 2562 C. or a mixed material that contains the low-boiling point material.

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 starter includes a motor configured with a direct current motor. The direct current motor has a brush and a commutator. The brush is a sintered material formed of graphite and a copper powder. The commutator is formed of either copper or a copper alloy that has a copper content of 99% or more. A surface of is a sliding portion of the commutator which has sliding movement with the brush is provided with a graphite cover-layer that contains graphite as a main component. The graphite cover-layer contains a hard compound which has a Vickers hardness higher than 10 GPa and a metal sulfide solid lubricant.

A rotary connector includes a rod-shaped rotating side electrode rotatably supported by an external shell case and a fixed side electrode supported by the external shell case. Rotating side electrode and the fixed side electrode are disposed so that one end parts of the electrodes face each other spaced apart to form a clearance therebetween, the rotary connector further has a cylindrical liquid impregnated member, disposed so as to surround the outer peripheral surface close to the one end part of the fixed side electrode, that covers the clearance formed between the fixed side electrode and the rotating side electrode from outer peripheral sides of the fixed side electrode and the rotating side electrode, and the region formed by one end part of the rotating side electrode, one end part of the fixed side electrode, and the inner peripheral surface of the liquid impregnated member is filled with liquid metal.

A wire brush for a slipring includes a contact section, from which a stabilizer arm is extending backwards towards the brush block of the slipring. The stabilizer arm holds a friction section, which is in friction contact with the contact section at a friction contact area. Such contact, in operation, generates internal friction within the brush when the brush is moved and, therefore, suppresses oscillations of the brush.

A current collector and a conductor line system having such a current collector. The current collector has a holder and a carbon brush arranged in carbon brush support movable relative to holder in a feed direction from and to the conductor line. The carbon brush is movable in a feed direction from and to conductor line. The disclosure solves the task of achieving better and reliable guiding of the carbon brush on the conductor line and simpler design of the current collector, using a current collector in which the carbon brush is additionally movable in a transverse direction running essentially across the longitudinal direction, a spring element being provided between the carbon brush and holder.

A method for producing a shaft grounding ring includes providing a shaft grounding ring having an annular main body and contact elements arranged on the main body. The contact elements are electrically conductive and plastic-based. The contact elements are configured to establish an electrically conductive sliding contact with a circumferential surface of a shaft or of a sleeve placed onto the shaft. The contact elements are elastically bendable such that the contact elements are configured to preload the electrically conductive sliding contact. Additionally, the method includes thermally preconditioning the shaft grounding ring before use.

Methods and apparatus to mitigate electrical voltage on a rotating shaft are disclosed. An example grounding brush system mitigates electric current in a rotating shaft, the grounding brush system comprising: a brush assembly configured to be disposed proximate a motor shaft, the brush assembly having conductive filaments configured to be in electrical continuity with the motor shaft when the brush assembly is disposed proximate the motor shaft; and a conductive coating comprising a base liquid and conductive particles, in which the conductive coating coats at least respective portions of the conductive filaments so as to provide an electrical path between the conductive filaments and the motor shaft.

A wire brush for a slipring includes a contact section, from which a stabilizer arm is extending backwards towards the brush block of the slipring. The stabilizer arm holds a friction section, which is in friction contact with the contact section at a friction contact area. Such contact, in operation, generates internal friction within the brush when the brush is moved and, therefore, suppresses oscillations of the brush.

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.