of the corresponding semiconductor switches s 2 s 4 it is preferred that the partial control of the semiconductor switches that are to be partially controlled is selected so that said semiconductor switches comprise an effective resistance that lies in a region between the half line resistance and the double line resistance of the phase lines and in particular corresponds to the line resistance furthermore the effective resistance value that is determined by means of the partial control process is limited by means of the thermal loading capacity of the mosfets fig2 a and 2 b plot the braking torques over the rotational speed of an electrical machine 2 wherein the phase lines of the electrical machine 2 are mutually connected in fig2 a by way of a phase leakage whereas in the case in fig2 b the phase lines of the electrical machine 2 are mutually connected by way of semiconductor switches that are only partially controlled so that an additional resistance is provided between the phase lines it is evident that the progression in the case of fig2 b is displaced in the region of the higher rotational speeds so that a lower braking torque is set in the case of lower rotational speeds furthermore it is evident that the braking torque also reduces in a range of higher rotational speeds fig3 shows a flow diagram for illustrating a method for operating an electrical machine in the event of a malfunction if it is established during a query in step st 1 that a malfunction has occurred and in this malfunction one of.