A method is provide for the safe starting and/or stopping of a rotor of a rotor spinning machine for the production of yarn, the spinning machine having a multiple number of rotors that rotate in a respective rotor housing covered by a lid. Each rotor is driven by its own motor and is held in at least one radially and/or axially active magnetic bearing by means of a position controller. Each motor is in communication with a control unit through a data connection to control the rotor in various operating states. One or more of the following conditions is checked against predetermined target values or states: (1) control for the drive of the rotor; (2) position control for the active magnetic bearings; (3) data connection for controlling the motor. In the event that the predetermined target values or states are not met, start of the rotor is blocked or the motor that is already running is selectively stopped.

The invention relates to a rotor spinning machine and to a method for operating a rotor spinning machine with a control device, an open-end rotor spinning device and a supply unit feeding at least two fiber slivers into the open-end rotor spinning device, which supply unit has an opening roller for opening fiber slivers and a feed apparatus with a first and a second feed roller, which can be operated independently of one another by means of the control device, for a first fiber sliver and a second fiber sliver. In order to provide a rotor spinning machine as well as a method for operating a rotor spinning machine, which enables easy setting of the drafting speeds of the supply unit having at least two feed rollers, it is provided that the control device determines an individual drafting speed of one feed roller for producing a yarn with predetermined yarn properties from a single fiber sliver fed by means of the first feed roller, and coordinates a first drafting speed of the first feed roller and a second drafting speed of the second feed roller with one another in such a way that the sum of the first and second drafting speeds corresponds to the individual drafting speed.

A method for operating a textile machine with several identical workstations which each have a basic requirement for negative pressure for regular production operation and an additional requirement for negative pressure following an interruption to production at the workstation, and with a vacuum system with limited suction force to exert the negative pressure on the workstations. A minimum negative pressure (p.sub.min) is set and the number workstations simultaneously supplied with additional negative pressure is limited so that the minimum negative pressure (p.sub.min) is always met. In accordance with the invention, a sub-negative pressure (p.sub.sub) is specified which is below the minimum negative pressure (p.sub.min) and, if a specified event occurs, the number of workstations simultaneously supplied with additional negative pressure is temporarily limited so that the sub-negative pressure (p.sub.sub) is always met.

A method for operating a textile machine with several identical workstations which each have a basic requirement for negative pressure for regular production operation and an additional requirement for negative pressure following an interruption to production at the workstation, and with a vacuum system with limited suction force to exert the negative pressure on the workstations. A minimum negative pressure (p.sub.min) is set and the number workstations simultaneously supplied with additional negative pressure is limited so that the minimum negative pressure (p.sub.min) is always met. In accordance with the invention, a sub-negative pressure (p.sub.sub) is specified which is below the minimum negative pressure (p.sub.min) and, if a specified event occurs, the number of workstations simultaneously supplied with additional negative pressure is temporarily limited so that the sub-negative pressure (p.sub.sub) is always met.

A method is provided for operating a spinning machine with a multiple number of spinning stations. In the normal case, the individual spinning stations are supplied with a fiber material and produce a yarn. Upon the occurrence of predefined events, yarn production is interrupted at individual or all spinning stations, whereas such spinning stations are, when required, subjected to piecing with the assistance of a piecing process in order to start up yarn production again. The respective piecing is carried out with the assistance of handling tools associated with the spinning machine. The individual spinning stations are classified on the basis of one or more production-related parameters, and that, if more piecing processes are to be carried out at the same time than can be carried out by the handling tools, at least the selection of the spinning station to be subjected to piecing next is carried out under consideration of the specified classification.

A method is provided for operating a spinning machine with a multiple number of spinning stations. In the normal case, the individual spinning stations are supplied with a fiber material and produce a yarn. Upon the occurrence of predefined events, yarn production is interrupted at individual or all spinning stations, whereas such spinning stations are, when required, subjected to piecing with the assistance of a piecing process in order to start up yarn production again. The respective piecing is carried out with the assistance of handling tools associated with the spinning machine. The individual spinning stations are classified on the basis of one or more production-related parameters, and that, if more piecing processes are to be carried out at the same time than can be carried out by the handling tools, at least the selection of the spinning station to be subjected to piecing next is carried out under consideration of the specified classification.

A method at a workstation of a spinning machine or winding machine supplies an auxiliary thread from a thread nozzle to a suction assigned to the workstation, the auxiliary thread stretched between the thread nozzle and the suction. The auxiliary thread is severed to form a thread section protruding into the suction and a thread section extending into the thread nozzle, wherein the thread section protruding into the suction is carried away by the suction. The thread section extending into the thread nozzle is grasped with a thread receiver such that the thread section extending into the thread nozzle extends between the thread nozzle and the thread receiver. The thread section extending into the thread nozzle is severed to form a thread section remaining in the thread nozzle and a thread section coming from the thread receiver. The thread section coming from the thread receiver is transferred to the suction of the workstation. The thread section coming from the thread receiver is grasped with a capture arrangement adjacent a tube at the workstation prior to starting a process of winding the thread section coming from the thread receiver onto the tube.

A method at a workstation of a spinning machine or winding machine supplies an auxiliary thread from a thread nozzle to a suction assigned to the workstation, the auxiliary thread stretched between the thread nozzle and the suction. The auxiliary thread is severed to form a thread section protruding into the suction and a thread section extending into the thread nozzle, wherein the thread section protruding into the suction is carried away by the suction. The thread section extending into the thread nozzle is grasped with a thread receiver such that the thread section extending into the thread nozzle extends between the thread nozzle and the thread receiver. The thread section extending into the thread nozzle is severed to form a thread section remaining in the thread nozzle and a thread section coming from the thread receiver. The thread section coming from the thread receiver is transferred to the suction of the workstation. The thread section coming from the thread receiver is grasped with a capture arrangement adjacent a tube at the workstation prior to starting a process of winding the thread section coming from the thread receiver onto the tube.

A textile machine that can comprise a first negative pressure point for producing a thread, a second negative pressure point for sucking in the thread and a negative pressure system which can be designed and arranged to be brought into a fluidic connection with the first negative pressure point. Alternatively, the first negative pressure system can be designed and arranged to be in a fluidic connection with the first negative pressure point. The textile machine can comprise a second negative pressure system that can be brought into a fluidic connection with the second negative pressure point. Alternatively, the second negative pressure system can be designed and arranged to be in fluidic connection with the second negative pressure point. A connection between the first negative pressure system and the second negative pressure system is designed such that the connection can be selectively established or interrupted.

A textile machine that can comprise a first negative pressure point for producing a thread, a second negative pressure point for sucking in the thread and a negative pressure system which can be designed and arranged to be brought into a fluidic connection with the first negative pressure point. Alternatively, the first negative pressure system can be designed and arranged to be in a fluidic connection with the first negative pressure point. The textile machine can comprise a second negative pressure system that can be brought into a fluidic connection with the second negative pressure point. Alternatively, the second negative pressure system can be designed and arranged to be in fluidic connection with the second negative pressure point. A connection between the first negative pressure system and the second negative pressure system is designed such that the connection can be selectively established or interrupted.