the current through the electric motor 5 when the luggage compartment flap 3 is blocked by an end stop furthermore the end stop may also be signaled to the control unit 9 by a corresponding sensor for comfort reasons the calibration process should not be carried out often provision is now made to detect when the clutch has disengaged and to carry out a calibration preferably only when the clutch has disengaged for this purpose the rotational speed of the electric motor 5 is monitored for example by evaluating the position signal ps and a disengagement of the clutch 8 is inferred for example on the basis of a change in the rotational speed signal data regarding the rotational speed may be derived for example from detected position information by determining a change in position over a defined time period by means of a derivation of the rotational speed data with respect to time it is thereby possible to detect a change in rotational speed owing to the inertia of the overall system that is to say the mass of the luggage compartment flap 3 with the moment of inertia of the electric motor 5 and of the gearing 6 and also the inertia of the linkage 7 changes in rotational speed take place during the electromotive operation of the luggage compartment flap 3 which however do not exceed a certain rotational speed gradient value in the event of an abutment of the luggage compartment flap 3 against an obstruction or as a result of a force being exerted on the luggage compartment flap which exceeds that during a manual actuation of the luggage compartment flap 3 generally as a result of the exertion of.