In the present invention the positions of the slots or poles of the stator of an electric motor are changed in order to reduce the harmonics caused by the stator winding and any vibration caused by these harmonics. In the present invention a shape function is defined according to the new placement positions for the stator slots and/or stator poles. A conversion function sums for the slot placement positions to be given to equidistant stator slotting placement. In one embodiment of the invention the conversion function is the sum of sinusoidal functions and in its amplitude small in relation to the distance between the slots.