@proceedings{Łukasz Breńkacz2023, author = "Łukasz Breńkacz and Paweł Bagiński and Artur Andrearczyk", abstract = "Abstract Within the framework of the research carried out, an active foil bearing was designed and tested. Typical gas foil bearings have a high starting torque. This is because the top foil must be clamped to the shaft during assembly. Only if the speed is high enough does a layer of air form between the top foil and the rotating shaft, which, thanks to the bump foils' ability to self-adjust their shape, allows the bearing to operate. This article presents an innovative (one-of-a-kind) active foil bearing. The diameter of the bearing sleeve can be changed using an electric motor mounted in the bearing. These modifications allow the dynamic properties of the rotor to be controlled. It is also possible to reduce the starting torque by increasing the diameter of the bearing sleeve during start-up. The article presents the results of the friction torque tests conducted on the newly developed bearing with variable geometry. This paper shows the starting torque characteristics obtained for bearings with different geometries.", doi = "DOI 10.26083/tuprints-00027602", editor = "Stephan Rinderknecht, Benedikt Sch{\"u}{\ss}ler, Sarah Schwarz", title = "{C}hanges in the friction torque of an active foil bearing", url = "http://brenkacz.com/images/publications/Brenkacz,%20Baginski,%20Andrarczyk%20-%202023%20-%20Changes%20in%20the%20friction%20torque.pdf", year = "2023", }