Patent ID: 8063590

Claim:
A method for detecting blocking of a direct current motor ( 10 ) for a blower of a motor vehicle, comprising the following steps: deactivating the direct current motor ( 10 ) for a defined time period (T off ) by a computer unit ( 20 ) with the aid of a switching means ( 18 ); within the defined time period (T off ), measuring an induced voltage (U) of the direct current motor ( 10 ) at least one subsequent time (t a , t b ) and forwarding the induced voltage (U) to the computer unit ( 20 ); maintaining a deactivated state of the direct current motor ( 10 ) if the induced voltage (U) undershoots a predetermined threshold value (U th ), or again activating the direct current motor ( 10 ) if the induced voltage (U) of the direct current motor ( 10 ) does not undershoot the predetermined threshold value (U th ); after reactivation of the direct current motor ( 10 ), forwarding to the computer unit ( 20 ) a measurement variable (X mess ) that is dependent on a motor current (I) and is measured by means of a measuring device ( 16 ) and storing said measurement variable (X mess ) as a reference value (X ref ) in a memory ( 22 ) of the computer unit ( 20 ), wherein the measuring device ( 16 ) measures the measurement variable (X mess ) during the operation of the direct current motor ( 10 ) and forwards it to the computer unit ( 20 ) for a comparison with the reference value (X ref ) stored in the memory ( 22 ); and deactivating again the direct current motor ( 10 ) by the computer unit ( 20 ) with the aid of the switching means ( 18 ) for the defined time period (T off ), if the measured measurement variable (X mess ) deviates from the reference value (X ref ) stored beforehand in the memory ( 22 ) of the computer unit ( 20 ) by more than a definable tolerance value.