In a device for regulating the power output of an electrical generator in motor vehicles having an internal combustion engine, in which the generator has a regulator unit, which prevents exceeding at least one limiting temperature by regulation, the regulator unit is connected via a bidirectional interface to an electronic control unit assigned to the internal combustion engine. The control unit and the regulator unit are designed in such a way that the regulator unit, after transmitting at least one value relevant to the limiting temperature from the control unit to the regulator unit, stores the particular applicable limiting temperature determined by this value.