Patent ID: 7111446

Claim:
A method for operating an open-end rotor spinning unit, which comprises a spinning rotor that rotates during the spinning operation at a high speed in a closed rotor housing which is closed by a cover element which is moveable between open and closed positions, with the spinning rotor being operated by an individual electric motor drive and supported with its rotor shaft in a smoothly running bearing assembly, said method comprising the step of biasing and rotating the spinning rotor by an airflow resulting from a vacuum which is generated in the rotor housing and while the drive is disconnected from its energy supply and is operated as a generator, monitoring at least one of the electric quantities that develop during the generator operation of the drive, generating a signal upon the monitored electric quantity exceeding a predetermined threshold value which can only be attained when the cover element is properly closed, processing the signal in a control unit so as to cause the cover element on the rotor housing to be locked in the closed position, and then connecting the drive to its energy supply to rotate the spinning rotor.