The present disclosure relates to an electric drive motor (101; 201) for a vehicle. The electric drive motor (101; 201) has a stator (103) having a plurality of slots (107); and a rotor (102; 202) having a plurality of poles (106; 206). The poles (106; 206) each have at least a first permanent magnet (104; 204) centred on a d-axis of the pole (106; 206); and a plurality of flux barriers (109; 209) for disrupting at least an n-th order torque harmonic of the electric drive motor (101). Proximal to an outer surface of the rotor (102; 202), a first angular period (x11) between first and secondary flux barriers is defined by the equation (xi1=tao/n1), whereby: (xi1) is the first angular period; (tao) is the pole step; and n1 is an order number of a torque harmonic to be disrupted.