In a rotating machine, for example heteropolar, auxiliary poles (14) are placed in practically the field poles (4) and close to the peripheral of a salient section (.delta.) of rotor (2), the same azimuth symmetry plane as the poles are supplied by a current (i) regulated by a power supply and auxiliary regulation device (16), the armature current (I) and rotation speed (N) of the rotor expose armature conductors (8) in commutation to an equalizing flux providing for arc-free commutation. Auxiliary poles can be supplied with a current regulated by the field current to cancel the currents flowing in the armature conductors on the field poles. These machines, for example also acyclic with voltage step-up, have high specific power and efficiency, and can be employed for example, in electric traction or propulsion.