To obtain a rotating electrical machine preventing a functional failure and shortening of the life of brushes caused by a temperature rise of the brushes installed to a vehicle AC power generator or a motor generator. A brush holder holding brushes supplying a field current to a rotor is provided with brush temperature suppressing metal members installed substantially parallel to the brushes in the vicinity of abutment portions of the brushes and slip rings in point-, line-, or surface-contact with the brushes at least at one point besides energization terminals. The brush temperature suppressing metal members not only diffuse heat generated at the brushes, but also function as a heat capacity for a case where a large amount of heat is generated in a short time, such as during regenerative power generation and a start-up operation, and thereby prevent an excessive temperature rise of the brushes.

A discharge device for discharging electric currents from a rotor part of a machine having a shaft. The discharge device has a displaceable contact element received at least partially in a guide unit and serving to form an electrically conductive sliding contact between a sliding contact surface of the contact element provided for forming the sliding contact and a shaft contact surface, the contact element being connected to the guide unit and/or a retaining element of the machine in an electrically conductive manner and the contact element being pre-loaded towards the shaft contact surface by a spring element, the contact element being wetted at least partially by a lubricating and cooling fluid, the guide unit comprising a guiding part for receiving the contact element and a retaining part for receiving the guiding part, the retaining part and the guiding part forming a duct for the lubricating and cooling fluid.