The invention relates to a system for the electronic commutation of a brushless DC motor (1) having three phase windings (u, v, w) which are electrically displaced by 120°, comprising a semiconductor bridge (4) consisting of six power semiconductors (S1 to S6), which drives the phase windings (u, v, w) for generating a rotating magnetic stator field, a control unit (6) which correspondingly drives the power semiconductors (S1 to S6), and a device for detecting the respective rotational position of a rotor exhibiting a permanent-magnetic magnet wheel, the device for detecting the rotor position being constructed as sensor-less evaluating unit (8), for evaluating the voltage induced by the rotating magnet wheel which can be measured at the winding terminal (U, V, W) of the motor which is not currently driven. It is the object of the present invention to achieve a reduction of running and commutation noises whilst maintaining the inexpensive and fault-insensitive sensorless rotor position detection. For this purpose, the control unit (6) drives the power semiconductors (S1 to S6) in twelve switching states, which are different with respect to the magnetic field direction effected in each case, by means of a 12-step commutation over one electrical revolution of the DC motor in dependence on the rotor positions.