148 Ë 5 HTS Maglev experimental methods and set-up
- Force measuring accuracy,±0.1%.
- Vertical test speed, 10 mm/s (max.), 0.1 mm/s (min.).
- Horizontal test speed, 5 mm/s (max,), 0.01-0.03 mm/s (min.).
- Vertical maximum displacement,±150 mm.
- Vertical minimum test distance, 0.1 mm.
- Level (x−y) the maximum displacement,±50 mm.
- Horizontal displacement minimum test distance, 0.01 mm.
- Location: after each test back to the origin (0 points).
- Power supply, AC 220 V, 15 A (max.).
- Working temperature, 0°C–50°C
- Humidity, 10%–90%.
The maximal testing axial force is 1500 kgf, which is designed with the consideration
of the HTS Maglev bearing. This is a common knowledge in the last decade develop-
ment in FESS, from the cost-effective view. If we want to increase the capacity, we
should use assembly of several FESS. The ESC of 2–5 kWh can satisfy 90% of the
requirements for FESS, which is based on a mass of market research. The flywheel
rotor composed of metal or composite materials, with ESC of 5 kWh and rotation speed
of 15,000 rpm, is about 450 kg by the simulation calculation. Because of the limitation
of maximal line speed of metal materials, the weight of the flywheel rotor is about
750 kg if composed completely of metal at rotate speed of 15,000 rpm. This HTS Maglev
bearing measurement system has a reserve testing capacity for a metal flywheel rotor
of 1500 kg, in other words, a FESS with ESC of 10 kWh. If the 1500-kg rotor is composed
of metal and composite materials, the maximal ESC for testing FESS will be about
20 kWh. From experimental experience, the maximal horizontal force of HTS Maglev
system is always smaller than half of the maximal vertical force, so the maximal testing
radial force is set to 800 kgf.
Because of risk in flywheel tests at high speed, all the processes are controlled
remotely on the test platform. Some special technologies are applied to ensure the
precision of testing signal, such as the transition between RS 232/optical fiber and the
application of shielded wires. Furthermore, the key accessory equipment of the test
system, such as the vacuum pump, the cryogenic refrigerator and the water cooling
device, are also controlled on the test platform. Once a dangerous signal regarding
the vacuum degree, the temperature or the cooling system appears, the control system
will stop the ongoing experiment immediately to protect the safety of operators and
facilities.
References
[1]Krabbes G, Fuchs G, Canders WR, May H, Palka R. High temperature superconductor bulk
materials: Fundamentals - Processing - Properties control - Application aspects. Weinheim:
Wiley-VCH Verlag GmbH & Co. KGaA; 2006. p. 1–30.