A method for constant-current generation by means of a rotational energy source, a generator and a control circuit connected to the generator. Mechanical rotational energy is generated by the energy source and the mechanical rotational energy is transmitted to the generator rotor. The magnetic field distribution produced in the generator is controlled by the control circuit that controls the current distribution in the generator between load current and generator current by feedback control by generating an opposing magnetic field. The power uptake and the current output are adapted without losses and the alternating current generated by the generator is transferred to an averaging direct-current circuit. A suitable device for carrying out the method is also provided.