Yarn return unit for returning a yarn as well as a workstation of a textile machine comprising a yarn return unit

A rotor spinning machine, comprising:

• at least one workstation, the workstation comprising a spinning rotor mounted in a suspended manner in a radially acting magnetic bearing such that the spinning rotor rotates within the magnetic bearing during a spinning operation;
• the workstation further comprising a control system configured to identify of the spinning rotor from other different types of spinning rotors by comparing a system variable that varies between different types of spinning rotors with a reference value;
• wherein the system variable is one or a combination of:
• an energy consumption of the magnetic bearing;
• a radial position of the spinning rotor;
• or a resonant frequency of the spinning rotor;
• and
• based on the comparison of the detected system variable and the reference value, the control system configured to determine one or a combination of the following physical characteristics of the spinning rotor that differentiate the spinning rotor from other different types of spinning rotors:
• a mass of the spinning rotor, a volume of the spinning rotor, a material of the spinning rotor, and dimensions of a size or shape of the spinning rotor.