A protective circuit protects against overheating of the stator windings of an EC motor. The stator windings are connected to a semiconductor output stage which is designed for time-offset control of the stator windings using a driver circuit of a commutation controller. The protective circuit has two redundant sensor circuits, wherein two resistance-dependent sensor elements connected in series are provided in the first sensor circuit and one resistance-dependent sensor element is provided in the second sensor circuit. The first and the second sensor circuits are connected, respectively, to two evaluating circuits separated from each other and cause an interruption of the driver circuit using switch-off means when a system-specific resistance value of the first sensor element or the one sensor element associated with the second sensor circuit is reached.