Single-motor drive for a shaftless spinning rotor and method for operating same

In a shaftless spinning rotor assembly for an open end spinning machine, the spinning rotor assembly including an axial field motor having a stator, stator phase excitation circuits, and a permanent-magnetic rotor defining a spinning chamber, the stator and the rotor having respective bearing surfaces facing one another, and a combined magnet/gas bearing having gas outlet openings connected with a gas supply and communicated between the respective bearing surfaces of the rotor and the stator for forming a gas cushion for supporting the rotor spaced from the stator, the improvement comprising means for detecting an interruption of the gas supply, means for braking the rotor and means for actuating said braking means in response to detection of an interruption in the gas supply by said detecting means, said actuating means being operative to connect said braking means to a power supply to the stator, said braking means being operative to slow rotation of the rotor at a rate sufficient to reduce the rotational speed below a predetermined speed which would result in damage to the respective bearing surfaces, said reduction occurring before the beating surface of the rotor engages the bearing surface of the stator.