Electromagnetic Retarder and Assembly Comprising Such a Retarder

An assembly comprising a rotational driving mechanism of a drive shaft, and an electromagnetic retarder capable of slowing down the rotation of the drive shaft. The driving mechanism has a housing and a drive shaft extending along an axial direction. The electromagnetic retarder has a stator support fixed to the housing that has at least one relief extending along the axial direction, and in that the housing comprises at least one complementary relief cooperating with at least part of the relief of the stator support to fix the position of the stator support in relation to the housing along at least one direction contained in a plane perpendicular to the axial direction.