Su-Yu Wang, Jia-Su Wang, Yi-Yun Lu, and Wei Liu
5 HTS Maglev experimental methods and set-up
Experimental study data are the foundation of scientific research. Before the design
and development of the first manned HTS Maglev vehicle, a foundation of reliable
scientific evidence must first be obtained by excellent measurement methods and test
devices. Therefore, Jia-Su Wang and Su-Yu Wang propose some new test and analytical
methods, and the successful development of the measurement devices. This chapter
will introduce the measurement methods and devices.
5.1 Introduction
The potential engineering applications mentioned above are based on high-quality
HTS bulk samples, and it is especially important to investigate the levitation properties
between the YBCO bulk and the PM. Preparation methods and material properties for
HTS bulk are described in details by Krabbes et al. [1].
The measurements of the levitation forces can be realized by directly measuring
the forces between a YBCO bulk and a cylindrical PM. Normally, the YBCO bulk
is placed in the liquid nitrogen, while the levitation forces are measured directly
with a cylindrical PM moving up and down. The liquid nitrogen vessel is normally
placed below the PM. However, if the liquid nitrogen vessel is placed above the
PM, the measurement results can be more accurate since the PM is not affected by
the variation of temperature. This requires that the bottom wall thickness of the
liquid nitrogen vessel must be sufficiently thin. For accurate, rapid, and convenient
measurement of the levitation forces, a special thin bottom liquid nitrogen vessel has
been designed. It will be introduced later.
The measurement of levitation force is not the only important issue, measure-
ments of many other parameters of HTS Maglev are equally important. For example,
the guidance force as well as the cross stiffness, dynamic rigidity, relaxation time, etc.
are important. Synchronous measurements of multiple parameters are also required.
In order to meet these requirements, several special HTS Maglev measurement devices
have been designed and developed.
In order to investigate the levitation properties (levitation force, guidance for-
ce, trapping flux, etc.) of the HTS Maglev vehicle over the PMG, the SCML-01 HTS
Maglev measurement system [2] was developed at Jia-Su Wang’s group in 1999.
This measurement system has the measured HTS bulk over the PMG, thus, a spe-
cial cryogenic vessel is needed. Before the SCML-01, previous HTS Maglev tes-
ting systems had the PM over the HTS bulk. The YBCO was put inside a simple
cryostat container for liquid nitrogen, and a cylindrical PM was moving above.