International Journal of Applied Electromagnetics and Mechanics - Volume 33, issue 1-2

Authors: Fang, Xu | Qiu, Jie | Xiao, Hongli | Wang, Shuhong | Zhang, Jingyin | Gong, Weizhi | Xin, Ying

Article Type: Research Article

Abstract: In this paper, the transient short-circuit current of three-phase saturated core high temperature superconducting (HTS) fault current limiter (FCL) is investigated by using a method of combining 3-Dimensional (3D) finite element analysis (FEA) and equivalent dynamic nonlinear circuit model. The numerical computations are verified by the experiment results on a FCL prototype with rated voltage 380V. Based on the short-circuit current of three-phase saturated core HTS FCL with rated voltage 220 kV, the three-phase …transient magnetic field is simulated and analyzed. According to the simulation results, the transient short-circuit electromagnetic forces distribution is obtained. Show more

Keywords: Fault current limiter, finite element analysis, transient analysis, electromagnetic force

DOI: 10.3233/JAE-2010-1151

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 33, no. 1-2, pp. 503-510, 2010

Authors: Wang, Shuhong | Qiu, Jie | Liu, Xinying | Wang, Zhixuan | Zhu, Jianguo | Guo, Youguang | Lin, Zhi Wei | Wang, Yi | Xu, Wei

Article Type: Research Article

Abstract: This paper presents a hysteresis model for Type-II high temperature superconductor (HTS) by using simplified Preisach Model, in which the Preisach distribution function μ_k α, β) is determined only based on the B-H limiting loop. The nonlinear dynamic circuit model of the superconductor is established. In the circuit model, the hysteresis inductance and hysteresis loss described by using simplified Preisach Model are deduced. Applying the hysteresis circuit model, the currents flowing …in different superconductor layers of high temperature superconducting cable are simulated, as well as the hysteresis loss of the superconducting cable. The simulation results are verified by comparison with the data recorded in literatures. Finally, the influences of hysteresis on superconducting cable are analyzed and discussed. Show more

Keywords: Superconducting cable, hysteresis, Preisach model, current distribution

DOI: 10.3233/JAE-2010-1152

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 33, no. 1-2, pp. 511-517, 2010

Authors: Zhao, Xian-Feng | Zhou, You-He

Article Type: Research Article

Abstract: The equilibrium height (EH) of a levitated permanent magnet (PM) is investigated in an oscillation system composed of the PM and a high temperature superconductor (HTS). Two kinds of initial quasi-static magnetization processes are performed respectively, and then the EH is achieved after a damped vibration of the PM. A peak value of the EH, associated with a transitional magnetization height (TMH), is found for the first initial process. When the magnetization height (MH) is less …than the TMH, the EH increases with the increasing of the MH nonlinearly. Otherwise the EH decreases linearly with the MH. For the second initial magnetization process a minimum value of the EH is also presented. The magnetic energy of the system is believed to be responsible for these two different dependences. Show more

Keywords: Equilibrium height, initial magnetization process, Preisach model, current distribution

DOI: 10.3233/JAE-2010-1153

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 33, no. 1-2, pp. 519-525, 2010

Authors: Li and, Zhiyong | Wang, Yao | Wang, Wei | Wang, Xuyou

Article Type: Research Article

Abstract: In order to study the interaction between laser and MIG plasma, the radiation of YAG laser-pulsed MIG hybrid plasma is collected with fiber spectrometer. High speed video is also applied to study the coupling effect of laser-MIG hybrid welding plasma. Absorption of laser beam by the plasma is the main reason for the interaction, among which inverse bremsstrahlung process and photoionization are the dominant process. The spatial distribution of spectrum is also acquired to provide experimental …base for interaction analysis. The result shows that there is a high radiation intensity zone with great gradient in the center of laser-MIG hybrid plasma. An `ionized duct zone' is formed near the laser acting point. The above coupling effect provides a satisfied explanation for the better bead formation and more stable arc in the laser-MIG hybrid welding process. Show more

Keywords: Laser, plasma, hybrid welding, spectrum

DOI: 10.3233/JAE-2010-1154

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 33, no. 1-2, pp. 527-532, 2010

Authors: Albanese, Raffaele | Artaserse, Giovanni | Bellizio, Teresa | Rubinacci, Guglielmo | Fresa, Raffaele | Viola, Bruno | Palumbo, Maurizio Furno | Villone, Fabio | Liu, Yueqiang | Contributors, JET-EFDA

Article Type: Research Article

Abstract: The impact of the 3D effects on the dynamic response of the plasma in the JET tokamak is assessed on the time scale of interest for plasma magnetic control and stabilization. These effects are due to the limbs of the magnetic circuit and to the eddy currents in the 3D metallic structures. The plasma behaviour is taken into account by a specific matrix of modified inductances interacting with the remaining part of the system via a virtual …coupling surface. Show more

Keywords: Coupled problem, MHD, eddy currents

DOI: 10.3233/JAE-2010-1155

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 33, no. 1-2, pp. 533-540, 2010

Authors: Yu, Yonggang | Yan, Shanheng | Zhao, Na | Zhang, Qi

Article Type: Research Article

Abstract: The effects of boundary shape on the propagation form of the plasma jet in liquid media are studied. The construction and consecutive expansion processes of plasma jet in liquid are recorded by high speed digital camera system. The results indicate that the expansion construction of plasma jet in liquid is a typical Taylor cavity, and the axial expansion velocity of Taylor cavity in stepped-wall chamber is greater than that in cylindrical chamber. Based on the experiments, …numerical simulations of the interaction of non-steady plasma jet with liquid media are carried out. The change characteristics of pressure and velocity in plasma jet flow field have been obtained. Show more

Keywords: Plasma jet, taylor cavity, propagation form, numerical simulation

DOI: 10.3233/JAE-2010-1156

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 33, no. 1-2, pp. 541-548, 2010

Authors: Zhang, Liang | Han, Zandong | Wang, Bingfang

Article Type: Research Article

Abstract: The fuel balls counter is used to monitor the ball-passing information in the transmission pipeline of high temperature gas-cooled reactor (HTGR). It's the eye of fuel handling system and plays an important role in ensure the reactor's safe work. Regarding the high temperature and radioactive environment in fuel handling system, eddy current testing method is the best choice for fuel balls detection. Because of the magnetic shielding of the thick walled stainless steel pipe, the ball-passing …signal is weak. In order to increase signal to noise ratio and anti-interference ability, the parameter optimization of the sensor is performed by electromagnetic field simulation in this paper. The optimal goal is to maximize the coil impedance changing ratio between conditions of with and without ball inside pipeline. Show more

Keywords: Coil parameters, electromagnetic field simulation, finite element analysis, optimization design

DOI: 10.3233/JAE-2010-1157

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 33, no. 1-2, pp. 549-557, 2010

Authors: Tronco, Mário Luiz | Machado, José Márcio

Article Type: Research Article

Abstract: This paper describes an electronic device conceived to convert common web texts into sequences of corresponding Braille signals, which are immediately reproduced onto an array (keyboard) of electromechanical actuators. These actuators are reconfigurable in real time, displaying the Braille characters as matrices of points composed by small stems which can be lowered or raised according to the Braille code. The device, together with its conversion software package, can provide direct access to web texts in any …personal computer, thus avoiding the use of complicated Braille printers. Show more

Keywords: Braille characters, web texts, electromechanical actuators

DOI: 10.3233/JAE-2010-1158

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 33, no. 1-2, pp. 559-564, 2010

Authors: Zhang, G.H | Hu, S.Y.

Article Type: Research Article

Abstract: The advantage of geophone with large damping in receiving and compensating high frequency signals is studied theoretically and experimentally. It is found that, as the damping ratio increases, the frequency characteristic of geophone in domain frequency region approximates to the acceleration characteristic gradually, thus the receiving frequency bandwidth of land seismic acquisition is widened and the record of high frequency signals is enhanced. The adopted micro-electronic technology not only increases the geophone …damping largely, but also reduces the output impedance of geophone. The in-situ record data by self-designed geophones with large damping demonstrates higher visual frequency and S/N ratio, and stronger spectrum energy. The proposed method is expected to apply to the moving-coil geophone for high resolution seismic exploration. Show more

Keywords: Damping, moving-coil geophone, frequency characteristic, receiving frequency bandwidth, high resolution seismic exploration

DOI: 10.3233/JAE-2010-1159

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 33, no. 1-2, pp. 565-571, 2010

Authors: Perrin, Stéphane | Mawatari, Shingo | Kayata, Ryo | Maki, Koichi | Miya, Kenzo

Article Type: Research Article

Abstract: Electromagnetic (EM) sensors, by directly measuring the impeller of a rotating machine, offer a powerful way to detect not only defects on the impeller itself but to indirectly assess the condition of the bearings too, through the measurement of the displacement of the shaft and of the impeller. In this paper, a new method that uses statistical features computed on the time domain signals of a rotating impeller measured with several EM sensors is proposed. It …is shown that the proposed method allows the full characterization the wear-out (type and quantitative evaluation of the wear-out) in friction bearings. A real world application of this method is presented. Show more

Keywords: Electromagnetic sensor, friction bearing, eddy current

DOI: 10.3233/JAE-2010-1160

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 33, no. 1-2, pp. 573-579, 2010