This paper compares two motors as regard their behaviour during sensorless rotor position detection by means of injection of a high frequency signal. The motors are characterized by the presence of a ring around each pole and by different windings: a distributed coil winding and a concentrated coil winding. The effect of eddy currents in the magnets, due to the high frequency signal, is also considered. The effect of the slot opening is also taken in consideration. Finally, the comparison with two different PM rotor topologies, an interior PM motor and a INSET motor, is addressed.