An inductor alternator the stator member of which carries a DC excitation winding and an output winding, which may be multiphase, and a rotor member carrying a short-circuited winding. The short-circuited winding may be a squirrel cage or may comprise conductor bars connected in series with each other between end rings or else may be connected to form shortcircuited coils. The action of the machine is that circulating currents are generated in the rotor winding as the rotor rotates the direction of these currents reversing over pole pitches of the excitation winding and the multipole field so generated causes alternating currents to be generated in the output winding.