The invention relates to an electronically commutated electric motor. The electric motor has a stator and a rotor, in particular one formed with permanent magnets. The electric motor has a control unit, which is connected on the output side in particular via a power output stage to the stator and is designed to energize the stator so as to produce a rotating magnetic field. The electric motor has a power output stage with semiconductor switches. The power output stage is connected to the stator via at least one controllable switch disconnector. The control unit is designed to detect a defect of a semiconductor switch depending on a braking torque caused by the defect, in particular a change over time in the braking torque, on a rotor of the electric motor, and to activate the switch disconnector so as to disconnect the defective semiconductor switch from the stator.