A regulating method and device for loss-optimized operation of a separately excited synchronous machine having a stator and a rotor are provided. The method may include: providing reference values for stator and rotor currents, wherein the reference value for the stator current and/or the reference value for the rotor current or an auxiliary parameter representing the reference value of the stator current and/or an auxiliary parameter representing the reference value of the rotor current is dependent on a predefined reference torque; providing maximum values for stator and rotor currents; comparing reference values for the stator and/or rotor currents or an auxiliary parameter representing the reference value of the stator current and/or an auxiliary parameter representing a reference value of the rotor current to the corresponding maximum values and reducing of the reference torque by a torque value if at least one reference value reaches or exceeds the corresponding maximum value.