Electric machine having: - a housing, - a stationary part which is arranged in a rotationally conjoint manner in the housing, - a runner which is rotatably mounted in a receiving space of the stationary part, - a cooling device for discharging heat from the housing, for which purpose the cooling device provides, on the machine side, a closed cooling circuit for a cooling fluid, - a heat exchanger which is able to be acted on by cooling air and which is arranged on the housing and is coupled to the cooling device, wherein the heat exchanger is designed to be flowed through by the cooling fluid, and to ensure a substance separation between the cooling fluid and the cooling air in the heat exchanger, in that the cooling air is guided through cooling tubes of the heat exchanger and the cooling device is fluidically coupled to the heat exchanger, - a cooling-air duct for the supply and/or discharge of the cooling air, and - a fan as a shaft fan for introducing the cooling air into the cooling-air duct, wherein the fan has a separate fan housing, in which a fan wheel which is mounted so as to be drivable in rotation is arranged, wherein the fan housing has two opposing air inlet openings (44, 46), between which the fan wheel is arranged, and exactly one air outlet opening, which is arranged in a radial direction of the fan wheel and through which the cooling air provided by the fan is conveyed into the cooling-air duct, characterized in that the fan is formed as a two-channel fan, for which purpose the fan wheel is formed as a two-sided radial fan wheel, with the result that cooling air is correspondingly sucked in through both of the air inlet openings (44, 46) and conveyed into the cooling-air duct, and in that the air inlet openings (44, 46) are formed as a nozzle (54, 56). - a housing, - a stationary part which is arranged in a rotationally conjoint manner in the housing, - a runner which is rotatably mounted in a receiving space of the stationary part, - a cooling device for discharging heat from the housing, for which purpose the cooling device provides, on the machine side, a closed cooling circuit for a cooling fluid, - a heat exchanger which is able to be acted on by cooling air and which is arranged on the housing and is coupled to the cooling device, wherein the heat exchanger is designed to be flowed through by the cooling fluid, and to ensure a substance separation between the cooling fluid and the cooling air in the heat exchanger, in that the cooling air is guided through cooling tubes of the heat exchanger and the cooling device is fluidically coupled to the heat exchanger, - a cooling-air duct for the supply and/or discharge of the cooling air, and - a fan as a shaft fan for introducing the cooling air into the cooling-air duct, wherein the fan has a separate fan housing, in which a fan wheel which is mounted so as to be drivable in rotation is arranged, wherein the fan housing has two opposing air inlet openings (44, 46), between which the fan wheel is arranged, and exactly one air outlet opening, which is arranged in a radial direction of the fan wheel and through which the cooling air provided by the fan is conveyed into the cooling-air duct,