Commutator of the present invention includes electrically conductive part, resin part, ceramic part, first mixing part and second mixing part. First mixing part contains an electrically conductive material and a ceramic material in mixture. In first mixing part, a content of the electrically conductive material decreases and a content of the ceramic material increases from electrically conductive part toward ceramic part. Second mixing part contains the ceramic material and the resin material in mixture. In second mixing part, a content of the ceramic material decreases and a content of the resin material increases from ceramic part toward resin part.

A power terminal includes a terminal beam having a mating surface. A protective thermal coupler bridge is positioned adjacent the terminal beam having a bridge conductor, an insulating substrate and a bridge pad. The bridge pad has a mating surface. A variable resistive member is electrically coupled between the terminal beam and the bridge conductor to provide a shunt so that arcing does not occur when the power terminal is disconnected from the mating power terminal. The mating surface of the terminal beam is separable before the mating surface of the bridge pad is disconnected so that the resistance in the variable resistive member increases after disconnection of the main power terminal from the mating power terminal and prior to disconnection of the bridge pad from the mating power terminal to shunt the current through the bridge conductor and the variable resistive member during unmating.

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.

An electrical connection device is described which comprises a container comprising at least two seats, each seat being configured for containing an electrical connection element comprising a first contact element sliding contact element and a second sliding contact element, each connectable to a respective electric cable, and further comprising a tubular element inserted inside the container so that they can be rotated one with respect to the other, being the first sliding contact element integrally connected to the container and the second sliding contact element integrally connected to the tubular element to make a sliding contact between the contact elements.

An electrical connection device is described which comprises a container comprising at least two seats, each seat being configured for containing an electrical connection element comprising a first contact element sliding contact element and a second sliding contact element, each connectable to a respective electric cable, and further comprising a tubular element inserted inside the container so that they can be rotated one with respect to the other, being the first sliding contact element integrally connected to the container and the second sliding contact element integrally connected to the tubular element to make a sliding contact between the contact elements.

A slipring assembly comprises a slipring module having at least one slipring track, which is in electrical contact with at least one slipring brush. The slipring module comprises an isolating body holding the at least one slipring track. Furthermore a cooling element is embedded into or attached to the slipring module to remove heat from the slipring module and to increase the temperature of the at least one slipring track. This allows decreasing the temperature of the slipring module to increase the maximum transferable power and lifetime.

A slipring assembly comprises a slipring module having at least one slipring track, which is in electrical contact with at least one slipring brush. The slipring module comprises an isolating body holding the at least one slipring track. Furthermore a cooling element is embedded into or attached to the slipring module to remove heat from the slipring module and to increase the temperature of the at least one slipring track. This allows decreasing the temperature of the slipring module to increase the maximum transferable power and lifetime.