Abstract: An automotive electrical system with a generator has outputs for loads requiring a high and low voltage, e.g., a heater and a battery. A field-controlled a.c. generator with three-phase output windings has a low voltage main terminal and an auxiliary terminal for high voltage loads. A step-down transformer and a first rectifier connect the windings and the main terminal while a second rectifieer directly connects the windings and the auxiliary terminal. A selector switch having a open and closed positions is connected between the main terminal and the auxiliary terminal. A voltage regulator for controlling current through the generator field is connected to the main terminal. When the selector switch is open the generator provides a dual voltage output i.e.