A stator assembly that provides a concentric housing and stator, the stator radially positioned inside the housing, the housing having an inner surface, the stator having an outer surface radially facing the inner surface. One of the outer surface of the stator and the inner surface of the housing has recessed shapes and the other one of the outer and inner surface has protruding shapes. When the two shapes are arranged in a first relative position, the protruding shapes are inserted in the recessed shapes so that the stator can be mounted radially inside the housing along a central axis of the assembly, and in a second relative position that is angularly shifted relative to the first position around the central axis, the protruding shapes exert, against the one of the housing and the stator that bears the recessed shapes, a radial force that angularly and axially locks the stator.