Group members:

Superconductors for small scale levitation applications

Our research activities on small scale levitation applications properties are embedded in the framework of a joint 3-year DFG project with the Institute of Textile Machinery and High Performance Material Technology at the TU Dresden. The work is focused on the implementation and characterization of rotation ring-shaped superconducting magnetic bearings (SMBs) in high-speed textile processing machines for the mass production of short staple yarn.

Figure (a) Conventional ring-traveler twist element in ring spinning. The small c-shaped traveler is dragged along the immobile ring by the yarn. (b) Superconducting magnetic bearing as twist element. The magnetic ring is rotated by the yarn winding onto the spindle.

The majority of the short staple yarn produced worldwide today is spun with the traditional ring spinning technique. The productivity of this process depends on the rotational speed of the spindle. It is limited by friction in the so-called ring-traveler twist element. During the spinning process the traveler is dragged along the ring-rail by the yarn with up to 30000 rpm. The resulting friction causes wear of the twist element and melting of synthetic yarns at high spindle speeds due to strong heat generation.
The replacement of the ring-traveler twist element by a superconducting magnetic bearing was proposed to overcome this friction induced productivity limit. SMBs are inherently passive and contact-less bearings consisting, in this case, of a permanent-magnetic NdFeB ring acting as yarn driven traveler and a stationary superconducting YBa2Cu3O7-δ ring cooled on 77 K in a cryostat. With a first prototype of our SMB twist element in an open bath cryostat, several hundred meters of yarn were spun and the yarn quality was found to be comparable to conventional ring spun yarn. Therefore, a ring-shaped flow-through cryostat was developed and built in cooperation with our industrial partner evico GmbH. Superconducting rings were assembled from preselected bulks, prepared at the IFW by a melt texturing technique. Currently we  investigate experimentally as well as describe theoretically the static and dynamic behavior of the SMB, e.g. forces, displacements and precession, with respect to the ring spinning process.

Recent publications

M. Sparing, A. Berger, F. Wall, V. Lux, S. Hameister, D. Berger, M. Hossain, A. Abdkader, G. Fuchs, C. Cherif, L. Schultz; Dynamics of rotating superconducting magnetic bearings in ring spinning,
IEEE Transactions on Applied Superconductivity 26 (2016) accepted URL

A. Berger, M. Sparing,  M. Hossain,  D. Berger, G. Fuchs, A. Abdkader, C. Cherif and L. Schultz;
Cryogenic system for a ring-shaped SMB and integration in a ring-spinning tester,
IEEE Transactions on Applied Superconductivity 26 (2016) accepted

M. Sparing, M. Hossain, D. Berger, A. Berger, A. Abdkader, G. Fuchs, C. Cherif and L. Schultz;
Superconducting magnetic bearing as twist element in textile machines,
IEEE Transactions on Applied Superconductivity
25 (2015) Nr. 3, S. 3600504/1-4 URL

M. Hossain, A. Abdkader, C. Cherif, M. Sparing, D. Berger, G. Fuchs and L. Schultz;
Innovative twisting mechanism based on superconducting technology in a ring-spinning system,
Textile Research Journal
84 (2014) Nr. 8, S. 871-880 URL