The requirements for freedom from maintenance, long life and quiet running are fulfilled by a standard FAG radial ball bearing. The FAG engineers have further developed this bearing and integrated a sensor that detects both the speed and the direction of rotation. Both these types of information are required by the inverter that controls the output of the water-cooled three phase motor. The position of the accelerator pedal specifies the required speed. The inverter controller continuously compares the nominal value with the actual value. This comparison allows the output of the motor to be controlled. The speed sensor and the position of the accelerator pedal determine whether the motor should act as a drive or a generator. Since no external sensor is required, the section length and mass of the motor can be reduced.