Plates for retention of magnets

A rotor for an electric machine comprises a central core, arms extending radially relative to the core, these arms each comprising two rims extending on either side of the arms, permanent magnets positioned inside housings that are delimited by opposing lateral faces of adjacent arms, an outer face of the core extending between adjacent arms, and the rims of the arms of the rotor. Plates made from a material more flexible than the permanent magnets are positioned between the rims of the arms and the face of the permanent magnet facing away from the axis of the rotor to hold the magnets. The plate having, in the axial direction, a height close to the height of the permanent magnets, the ratio between the width of the plate and that of the magnet being between 0.9 and 1.1, without being equal to 1.