Abstract: An electric retarder for vehicle is provided comprising on the one hand an inductor stator comprising a ring of electric coils (3) supported by an annular framework (1), which framework includes a central socket (5), radial arms (6) extending this socket and a ring (8) carried by these arms and supporting the coils, and on the other hand, an armature rotor comprising two magnetic disks (20) both connected, through rings of bent arms (14), to a central collar (15), itself secured angularly to a section (17) of the shaft of the vehicle to be slowed down. The socket has a truncated cone shape, the collar is connected to a central cylindrical pot (16) covering the narrow end of the socket and the shaft section is mounted in this socket via a small bearing (19) housed in the pot and a large bearing (20), of the axial thrust type, disposed at the widened end of the socket.

Abstract: An electric speed reducer of low power designed essentially for equipping home trainers comprises an armature rotor composed of two parallel discs of magnetic material fastened to the same shaft. The shaft is itself mounted on a suitable frame through bearings. The inductor stator is arranged so as to be mountable radially removably between the two discs, and comprises for this purpose a single pair of cores of cylindrical or prismatic material whose generators are parallel with the axis of the speed reducer, and of which only the first is surrounded by a coil of electric wire.

Abstract: An electric retarder is provided for braking the transmission shaft (A) of a vehicle, in which the stator comprises at least one ring of coils (1) supported by a transverse plate (2) itself stiffened by a rib. The portion (7) of the stiffening rib of the plate, situated at the level of the axis (X) of the retarder, is disposed inside the ring of coils and is connected by radial extensions (10) each passing between two consecutive coils to outer rib sections (8,9) extending as far as the periphery of the plate. Thus the overall width L.sub.2 of the stator may be reduced for a given width l of the ring of coils, which makes standardization of the manufacture of the rotors possible in some cases.