Modelling and construction of a compact 500 kg HTS magnetic bearing

Abstract

The progress of heavy-load HTS bearings depends on improvements in design, material quality and reliable cooling. We have constructed, manufactured and tested a 200 mm HTS journal bearing with a thermally encapsulated YBCO ring. For maximum force the larger gap due to the bearing cryostat (>4 mm) requires adjustment of the magnetic excitation pole distance and the Fe collector shim thickness. HTS material progress is obtained by top-seeded single- or multiple-grain growth which increases the averaged trapped magnetic flux density. Successful YBCO ring growth with radial c axis distribution by seeding the inner ring surface has been performed. The encapsulation ensures a substantially reduced cryogenic effort and stabilizes bearing operation at 78–79 K.

Influence of ZnO doping on the properties of single domain YBCO bulks fabricated by RE+011 TSIG process

“…there are some local lower T c superconducting regions existing in the YBCO matrix, which can act as effective flux pinning centers when the superconductivity of the lower T c regions is destroyed to normal state. It is said that Zn +2 additions are more favorable to substitute at Cu (2) and the superconductivity is locally suppressed around Zn-substituted sites with a diameter of about 2-3 nm. 34 The weak superconductivity regions, compared to the coherence length of YBCO, can be effective δT c flux pinning centers.…”

“…YBCO bulk superconductor can be widely used for different kinds of applications such as field trapped magnets, magnetic bearing and motors, [1][2][3][4][5][6][7][8][9] due to its high T c , high critical current density (J c ), large levitation force and self-stability levitation. Non-superconducting Y 2 BaCuO y (Y211) and RE 2 Ba 4 CuMO y (REM2411, M=U, Mo, Zr, Bi, Nb, W, etc.)…”

“…18 The substitution of Zn at Cu sites attracted more attention because it is a non-magnet ion and due to its improvement of superconducting properties of YBCO despite the decreasing T c . It has been reported that J c and trapped field can be enhanced by the introduction of local nanometer-scale weak superconducting regions due to Zn substitution for Cu (2) in CuO 2 planes of YBCO bulks fabricated by the TSMTG process.…”

The homogeneity of levitation force in single domain YBCO bulk

“…Top-seeded melt texturing growth (TSMTG) [1,2] is one of the most important and effective ways to fabricate high quality YBCO bulk superconductors with a high levitation force at 77 K. The high levitation force of well textured YBCO bulks has attracted many scientists to work on its applications, such as magnetic bearings [3,4], flywheels [5] and levitated transportation systems [6]. For a TSMTG single-domain YBCO bulk superconductor, it is known that the levitation force is dependent on many parameters, such as the critical current density and grain radius, grain orientation, thickness of the sample and the cooling temperature [7].…”

The effect of temperature gradient on the morphology of YBCO bulk superconductors by melt texture growth processing

“…Well-textured YBCO [1][2][3][4] is one of the most important and practical high temperature superconductors due to its high T c and high J c in magnetic field, especially the high levitation force, which makes it possible for various applications, such as in magnetic bearing [5,6], motors [7], as trapped flux magnets (magnetic separation, etc.) [8,9] and no contact magnetic levitation transport system [10], etc.…”