Patent ID: 8294398

Claim:
An electronically commutated one-phase motor ( 20 ) having a stator having at least one winding strand ( 30 , 32 ; 30 ′) and a permanent-magnet rotor ( 22 ), which latter induces, as it rotates, a voltage (u ind ) in said at least one winding strand ( 30 , 32 ), and an electronic calculation device ( 26 ) which is implemented to repetitively execute, during motor operation, the steps of: a) sampling the induced voltage (u ind ) in a currentless winding strand ( 30 , 32 ) during a predetermined portion ( 72 ) of the induced voltage, in order to obtain a plurality of analog voltage values; b) digitizing the analog voltage values, in order to obtain a plurality of digitized voltage values; c) ascertaining any difference between a present digitized voltage value (new sample) and a digitized voltage value previous to said present value (old sample); d) ascertaining the sign of the difference; e) ascertaining the number (X) of voltage values having a positive difference; f) ascertaining the number (Y) of voltage values having a negative difference; g) as a function of a ratio between said two numbers (X; Y), ascertaining the rotation direction (DIR) of the rotor ( 22 ).