Process for operating a generator, and circuit for carrying out said process

The invention relates to a process for operating a generator with a plurality of generator windings in which a voltage is induced. When rotational speeds or voltage supply are low, at least two of the generator windings are connected in series and when rotational speeds or voltage supply of the individual generator windings are higher, said windings are connected in parallel thereby reducing the voltage of the generator. The overall voltage of the generator is consequently easily maintained in a predetermined range without the need for complicated voltage regulators. High output voltages are also produced when rotational speeds are low and operate electrical apparatus, in particular fuel injection devices. The process according to the invention can also be used for other active voltage sources, such as solar cells, batteries etc. which do not provide a constant voltage supply but have consumers which require a substantially constant voltage.