An electric drive includes a motor assembly, an output assembly, a transmission stage and one or more power electronics units connected to one or more electric voltage sources in order to control electrical sub-phases of electric machines of the motor assembly. The electric machines have motor shafts disposed parallel to one another. The transmission stage is connected to the motor assembly and also connected to the output assembly. The transmission stage has a transmission sun connected to the output assembly and has a plurality of transmission planets each connected to a respective one of the electric machines. The transmission planets are each fixed on a respective one of the motor shafts and are disposed in an annular manner around the transmission sun and roll on the transmission sun in a torque-transmitting manner. A method for operating an electric drive and a serial hybrid drive train are also provided.