Abstract: To provide a-c output at a voltage substantially higher than normal automotive voltage of 12-24 V, for example output voltage in the 80 to 90 V range to operate windshield and other glass pane heaters, a three-phase alternator is star-connected and has two armature windings which, for example, may be serially connected or may be separately wound, on the same stator, one winding being of comparatively few turns of heavy wire and connected to a rectifier to provide normal d-c on-board voltage for the vehicle, stored in a battery, the voltage being controlled by a voltage regulator connected to the d-c output terminals; the other winding, for example of a much larger number of turns of finer wire providing the high-voltage output at terminals adapted for connection to the heater wires in the windshield, or rear windows, or other window panes.