International Journal of Applied Electromagnetics and Mechanics - Volume 25, issue 1-4

Authors: Takezawa, M. | Wada, T. | Morimoto, Y. | Yamasaki, J.

Article Type: Research Article

Abstract: Domain structures of Fe-Si-B-Nb amorphous wires with a large diameter were investigated. A 10% increase of pulse output voltage due to large Barkhausen jumps in the Fe-Si-B-Nb wire at the diameter of 200 μm has been obtained which is less than expected due to decreased saturation and small domain size. Domain observation results indicate that the increase of the domain size in the inner core of the wire is important for high sensor output.

Keywords: Amorphous wire, domain structure, large Barkhausen jump, micro-motor

DOI: 10.3233/JAE-2007-773

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 25, no. 1-4, pp. 189-192, 2007

Authors: Mirzaei, Mehran | Mirsalim, Mojtaba | Cheng, Weiying | Gholizad, Hooshang

Article Type: Research Article

Abstract: In this article it is shown that a two dimensional analytical method can be coupled with reluctance networks for the analysis of solid rotor induction machines. By combining the advantages of both methods while avoiding their drawbacks, this coupling yields both an accurate and time-efficient computation. The analytical method is used in the solid iron rotor region, while the reluctance networks method is applied to obtain the electromagnetic fields in the stator core. In the air-gap, …both methods are implemented through the related boundary conditions. The comparison of the simulation results of the proposed method with the finite element ones shows the high accuracy of the presented method in electromagnetic computations. Show more

Keywords: Reluctance networks, analytical method, solid rotor, induction machines

DOI: 10.3233/JAE-2007-797

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 25, no. 1-4, pp. 193-197, 2007

Authors: Ionita, Valentin | Petrescu, Lucian | Razicheanu, Alexandru

Article Type: Research Article

Abstract: The paper is focused on the design, simulation and testing of an original experimental device, that allows the investigation of the magnetization processes in magnetic materials by Kerr microscopy. The adjustable magnetic field source is composed by two "magic" cylinders made with NdFeB permanent magnets. This source is coupled with a polarized reflected light microscope. The magnetic field is computed both by analytical formula and by 2-D and 3-D numerical simulation based on Finite Element Method.

Keywords: Kerr microscopy, permanent magnet cylinder, numerical simulation, finite element method

DOI: 10.3233/JAE-2007-782

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 25, no. 1-4, pp. 199-203, 2007

Authors: Melikhov, Y. | Park, C.M. | Lee, S.J. | Hauser, H. | Jiles, D.C.

Article Type: Research Article

Abstract: An improved model for simulations of the reflected intensity of the new magneto-optic angular displacement sensor for measuring small angular and spatial displacements of the surfaces of a material is presented. In this model, the diameter of the laser beam is taken into account which allows accurate description of the experimental response of the sensor. It was also confirmed that the differential changes in time dependence of intensity, not its absolute value, could serve as a …parameter for estimation of the amount of rotation of the sample surface. Show more

Keywords: Angular displacement sensor, magneto-optics, Faraday rotation, sensor

DOI: 10.3233/JAE-2007-864

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 25, no. 1-4, pp. 205-209, 2007

Authors: Takaya, Shigeru | Nagae, Yuji

Article Type: Research Article

Abstract: Developing a nondestructive method for estimating material degradation before crack initiation will contribute to improvement of safety and economical efficiency of fast breeder reactor plants. In this study, fatigue tests on type 304 stainless steel at 923 K, measurements of magnetic flux density, and microscopy studies were conducted. As a result, it was shown that the maximum value of variation of magnetic flux density during the fatigue tests increased linearly in relation to the number of …loading cycles and this magnetic property change was due to phase transformation. Show more

Keywords: Nondestructive estimation of material degradation, magnetic property, type 304 stainless steel, fatigue damage at elevated temperature

DOI: 10.3233/JAE-2007-895

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 25, no. 1-4, pp. 211-217, 2007

Authors: Di, Xiaojun | Moses, Anthony J. | Anderson, Philip

Article Type: Research Article

Abstract: Following a feasibility study performed using finite element modelling, a new measurement system has been developed to assess DC shielding efficiency of grain-oriented (GO) and non-oriented (NO) electrical steels. Some typical shielding efficiency results for various grades of electrical steel have been produced. Investigations in the paper show that this new method is a quick, easy and convenient way to evaluate the DC shielding performance of electrical steel panels.

DOI: 10.3233/JAE-2007-776

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 25, no. 1-4, pp. 219-224, 2007

Authors: Yao, Yingying | Ni, Guangzheng | Fang, Youtong | Hu, Guanzhong

Article Type: Research Article

Abstract: The paper describes a fast solving technique for the mechanical dynamic characteristic of electro-mechanical motional systems. Based on a sequence of finite element analysis, and a set of equivalent electrical circuit parameters extracted, the method incorporates electrical equation and vehicle's movement equation into state equations. Through test of an EMS-Maglev system, it reveals that the method gives reasonable results at very low computational costs comparing with transient finite element analysis.

Keywords: Mechanical dynamic analysis, movement, FEM, magnetically levitated vehicles

DOI: 10.3233/JAE-2007-822

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 25, no. 1-4, pp. 225-230, 2007

Authors: Maeda, Yoshitaka | Nakahata, Yasushi | Todaka, Takashi | Enokizono, Masato

Article Type: Research Article

Abstract: This paper presents a.c. magnetic power loss values measured on rare-earth permanent magnets. Magnetized permanent magnets are used for the investigation, and the effects of magnetization direction on magnetic power loss are examined. The result shows that the magnetic power loss, when the external magnetic field is parallel to the remanent magnetization direction, is larger than that when the external magnetic field is perpendicular to the remanent magnetization direction.

Keywords: Rare-earth permanent magnet, a.c. magnetic properties, eddy-current loss, hysteresis loss, three-dimensional magnetic field analysis

DOI: 10.3233/JAE-2007-775

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 25, no. 1-4, pp. 231-235, 2007

Authors: Lin, Zhi Wei | Zhu, Jian Guo | Guo, You Guang | Zhong, Jin Jiang | Wang, Shuhong

Article Type: Research Article

Abstract: Soft magnetic composite (SMC) materials are broadly used in low cost high performance electrical machines due to their magnetic isotropy, low eddy current loss, and capability to mould complex shapes. To optimise the performance of electrical machines, the three-dimensional (3-D) magnetic properties must be well understood and accurately modeled. For this purpose, a 3-D magnetic property measurement system was built and special sensing devices were fabricated. This paper presents, in detail, the magnetic flux density loci …and the corresponding magnetic field strength loci for an SMC material when the flux density loci were controlled to be circles lying in the xoy-, yoz-, and zox-plane at 50 Hz. Show more

Keywords: 3-D magnetic property, vector hysteresis loci, soft magnetic materials, soft magnetic composites

DOI: 10.3233/JAE-2007-783

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 25, no. 1-4, pp. 237-241, 2007

Authors: Tuleasca, Ioan | Kacprzak, Dariusz | Ohji, Takahisa

Article Type: Research Article

Abstract: A magnetic energy storage system made in an ellipsoidal enclosure and associated variable height superconductive coils is analysed and a comparison with other systems possessing the same superconductive material volume V_{s} and operating current I is performed. Two sets of geometrical dimensions are proposed, one associated with V_{s} =0.01 m^{3} and I=80 A and the other corresponding to V_{s} = 1.437 m^{3} and I=540 A. An …efficiency evaluation dependency W_{m}/V_{S} −V_{Threshold}/V_{Overall} , taking into account the safety magnetic field threshold B_{Threshold} =0.5 mT distance, is introduced. The results show a remarkable improvement achieved with the ellipsoidal structure in terms of stored energy as well as better shielding in respect to the equivalent system solenoid. Show more

Keywords: Energy storage, ellipsoidal enclosure, variable height coils, ferromagnetic shielding

DOI: 10.3233/JAE-2007-817

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 25, no. 1-4, pp. 243-247, 2007