The field regulated reluctance machine is perspective for automotive transport electric drives. In this machine, the switching of a stator current is done in function of a rotor position. The massive salient rotor of the electric machine does not contain windings. The stator is fulfilled in the body and iron of serial ac induction motor. The stator winding sections, which conductors lay above between rotor poles intervals, serve as a excitation winding, and others sections, which conductors lay above rotor poles, the role of a armature winding. In most cases, the optimal winding current waveform is distinct from the sine waveform. For a case of use separate current sources for each phase, the ideal is rectangular waveform. At the rotation of the motor, the each stator section winding pass from a zone of “excitation” to a zone of “armature”. The stator has finite number of phases. At switching stator currents, the part of a phase, in which there is a switching of an armature current, is in a zone of excitation, and another - in a zone of an armature. It causes additional losses in the rotor, because the rotor is fabricated massive (not laminated). For calculation of the losses first of all it is necessary to determine the factors, which influence on their value, and then, to estimate a degree of influence of each of them on value of switching losses. As such factors are taken: the form of the stator core, the form of a current in phase windings, and the number of stator winding phases. The calculation of losses is executed by the method of winding functions. The experimental data are received on a breadboard model of the 20 kW drive.