Abstract: The circuit effects a changeover from the traction configuration to the braking configuration or vice-versa in less than one millisecond. It includes the field winding (3) of the motor (1) disposed between a traction thyristor (12) and a main chopper (13) followed by a traction diode (14) and the armature of the motor, the field winding being in parallel with a free-wheeling diode (D5) and a shunt thyristor (THS).

Abstract: Static switching device for two machines making it possible to effect antkid control during drive operation and the controlling of the braking torque during brake operation. It comprises two circuits in parallel on the direct current source, a first circuit comprising, in the following order, a first chopper, a first smoothing inductance, an inductance of the first machine, a first distributing thyristor and an armature of the first machine and a second circuit comprising, in the following order, an armature of the second machine, a second distributing thyristor, a second smoothing inductance and an inductance of the second machine, the two circuits being connected together by two connections arranged on either side of the said first and second distributing thyristors, each of the connections bearing a distributing thyristor. Applications -- Controlling of electric motors used for the propulsion of vehicles.