A three-phase asynchronous motor comprises two major parts: the outer, fixed stator and the rotor contained therein. The stator is a sheet package consisting of thin, magnetically conductive electrical sheets. Inside these are copper wire coils to which the three three-phase current phases from the power electronics are connected. When a voltage is applied to them, a circumferential (rotating) magnetic field is produced. The stator’s rotating field induces a further magnetic field in the rotor – the rotor is carried along with the excitatory rotating magnetic field of the stator with a low rotational speed difference, i.e. asynchronously. If the rotor turns more slowly than the rotating magnetic field, the electric motor in the car works as a traction motor. In the opposite case, it becomes a generator and converts kinetic energy into electrical energy. The asynchronous motors do not produce any electrically induced drag losses in deenergized condition, which makes them highly efficient. Besides they can increase their output for a short period of time and thus maximize the performance of the car in the boost mode. Not only are they very light due to the aluminum rotor, they also have further advantages: They require little maintenance and are particularly robust. Furthermore, no rare earth elements are used in the production of the electric motors.