• Title, Summary, Keyword: Biot-Savart's law

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Comparison of Biot-Savart's Law and 3D FEM in the Study of Electromagnetic Forces Acting on End Winding

  • Kim, Ki-Chan
    • Journal of Electrical Engineering and Technology
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    • v.6 no.3
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    • pp.369-374
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    • 2011
  • An induction motor operated with high voltage source generally generates high current in starting mode and has a long transient time after being started. This large and sustaining starting current causes the end windings of the stator to have excessive electromagnetic force. This force is the source of vibration and has a negative and serious influence on the insulation of end windings. Therefore, designing the end winding part with an appropriate support system is needed. To design the support ring enclosing the end windings, we analyze the distribution of electromagnetic force on the end windings by applying the Biot-Savart's law and the 3D finite element method (FEM), and comparing two simulation methods. Finally, we verify the safety of the support structure of the end winding part using stress analysis, which is analyzed with the electromagnetic forces from the 3D FEM simulation.

Magnetic Field Analysis in Accordance with Line Configuration Type in Underground Transmission Systems (지중송전계통에서 선로의 구성방식에 따른 자계 해석)

  • Lee, Jae-Myeong;Lee, Jong-Beom
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.12
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    • pp.1673-1678
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    • 2015
  • This paper describes magnetic field on power cable in underground transmission systems. Based on specification which is being used in domestic power utility, magnetic field was analyzed in accordance with line arrangement, line burial depth and phase spacing. Magnetic field magnitude and its trend were understood in each circuit type such as double circuits, triple circuits and quadruple circuits of underground transmission systems. In addition, magnetic field was analyzed according to phase arrangement changing in each circuit. Finally, the proper phase arrangement configuration type was suggested by the evaluation of analysis result. Magnetic field was calculated by using Biot-Savart's law. According to the evaluated magnetic fields based on phase layout configuration in each circuit, it figured out that each of magnetic fields was different. As a result, this paper proposes a proper phase layout configuration for generating minimum magnetic field. It is evaluated that the phase layout configuration in each circuit proposed in this paper can be used at actual underground transmission systems.

Magnetic analysis of a finite solenoid (유한 솔레노이드의 자속밀도 해석)

  • Lee, Ju-Hee;Hwang, Seon;Lee, Dong-Yeon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.10
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    • pp.6453-6457
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    • 2015
  • In this paper, the theoretical analysis for a solenoid with a finite length was verified by the finite element simulation. The solenoids are widely being used in the field of mechanical, industrial, medical industry due to their simple structure and fast responses. Solenoid actuators use an electromagnetic force. A magnetic field is formed around the solenoid coil when a current is applied. The magnetic force generated by the magnetic field enables an inside plunger to move linearly. The axial and radial magnetic fields (magnetic flux density, B) at a certain point were calculated from the Biot-Savart's law and compared with the simulation analysis from the ANSYS-Magnetostatic S/W. Comparison result, an error exists in the error range, and could therefore verify the accuracy.

ELF 3D Magnetic Field Calculation and Elliptical Characteristic around Transmission Lines (송전선로 주변의 3차원 자기장 계산 및 elliptical 특성)

  • Myung, Sung-Ho;Kim, Sang-Beom;Shin, Koo-Yong;Lee, Dong-Il
    • Proceedings of the KIEE Conference
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    • pp.347-349
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    • 2001
  • 본 논문에서는 극저주파 전자계 장해의 공학적 평가에 있어 기본이 되는 송전선 주변의 3차원 자기장 예측기법에 대하여 기술하였다. 송전선 주변의 무한영역 극저주파 자기장 계산을 위해서는 Biot-Savart's law에 의한 3차원 자기장 해석방법을 사용하였으며 교류자계 벡터의 중요한 파라미터인 elliptical polarized 특성에 대하여도 고찰하였다.

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Numerical Analysis of Three-Dimensional Magnetic Resonance Current Density Imaging (MRCDI) (3차원 자기공명 전류밀도 영상법의 수치적 해석)

  • B.I. Lee;S.H. Oh;E.J. Woo;G. Khang;S.Y. Lee;M.H. Cho;O. Kwon;J.R. Yoon;J.K. Seo
    • Journal of Biomedical Engineering Research
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    • v.23 no.4
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    • pp.269-279
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    • 2002
  • When we inject a current into an electrically conducting subject such as a human body, voltage and current density distributions are formed inside the subject. The current density within the subject and injection current in the lead wires generate a magnetic field. This magnetic flux density within the subject distorts phase of spin-echo magnetic resonance images. In Magnetic Resonance Current Density Imaging (MRCDI) technique, we obtain internal magnetic flux density images and produce current density images from $\bigtriangledown{\times}B/\mu_\theta$. This internal information is used in Magnetic Resonance Electrical Impedance Tomography (MREIT) where we try to reconstruct a cross-sectional resistivity image of a subject. This paper describes numerical techniques of computing voltage. current density, and magnetic flux density within a subject due to an injection current. We use the Finite Element Method (FEM) and Biot-Savart law to calculate these variables from three-dimensional models with different internal resistivity distributions. The numerical analysis techniques described in this paper are used in the design of MRCDI experiments and also image reconstruction a1gorithms for MREIT.

Induced Current Calculation in a Human Body Model due to Magnetic field in High Speed Railway (고속철도내 자기장에 의한 인체 모델에서의 유도 전류 계산)

  • Han, In-Su;Lee, Tae-Hyung;Park, Choon-Soo;Kim, Ki-Hwan
    • Proceedings of the KSR Conference
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    • pp.208-213
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    • 2008
  • In recent society, the quality of human life has improved due to the use of electric appliances and the high powered electrical equipments. However, lots of electric appliances and equipments generate the electromagnetic field hazard. Many studies have been made about the wrong behavior of machines due to electromagnetic fields, the interferences in communication equipments, the possibility of the electromagnetic field hazard in human body, etc. There exist international standards about the RF equipments (ex. mobile phone, antenna, etc.). But, many researchers involved in power frequency electric and magnetic field only propose the prudential avoidance. In this paper, induced currents in a human body model due to magnetic fields in high speed railway are calculated by two dimensional impedance method. Power frequency(60Hz) magnetic fields are calculated and induced currents are simulated by Faraday's law. Induced currents are simulated with induced voltage, human body model impedances due to Ohm's law, magnetic fields derived from Biot-Savart's law and Transmission Line Method in high speed railway.

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Numerical Analysis of Unsteady Viscous Flow through Ship's Propulsion Mechanism of Weis-Fogh Type by Advanced Vortex Method (최신 와법에 의한 Weis-Fogh형 선박추진기구의 비정상 점성 흐름의 수치해석)

  • Ro, Ki-Deok
    • Proceedings of the KSME Conference
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    • pp.1407-1412
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    • 2004
  • The velocity and pressure fields of a ship's propulsion mechanism of Weis-Fogh type are studied by advanced vortex method. The wing of NACA0010 type and the channel are approximated by a finite of source and vortex panels, and the free vortices are introduced from the surface of their bodies. The viscous diffusion of fluid is represented by the core-spreading method. The velocity field is calculated on the basis of Biot-Savart law and the pressure field is calculated from the integration equation formulated by Uhlman. The flow fields of this propulsion mechanism are unsteady and complex, but the flow fields are clarified by numerical simulation.

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Development of a magnetic field calculation program for air-core solenoids which can control the precision of a magnetic field

  • Huang, Li;Lee, Sangjin
    • Progress in Superconductivity and Cryogenics
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    • v.16 no.4
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    • pp.53-56
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    • 2014
  • A numerical method of magnetic field calculation for the air-core solenoid is presented in this paper. In application of the Biot-Savart law, the magnetic field induced from the source current can be obtained by a double integration ormula. The numerical method named composite Simpson's rule for the integration is applied to the program and the adaptive quadrature method is used to adjust the step size in the calculation according to the precision we need. When the target point is in the solenoid and the intergrand's denominator may be zeroin the process of calculation, the method sill can provide an appropriate result. We have developed a program which calculates the magnetic field with at least 1ppm precision and named it as rzBI() to implement this method. The method has been used in the design of an MRI magnet, and the result show it is very flexible and convenient.

A Comparative Analysis of I-V Characteristics in a single Channel Superconducting Flux Flow Transistor (단일채널 고온초전도 자속흐름 트랜지스터의 I-V 특성 비교분석)

  • Ko, Seok-Cheol;Kang, Hyeong-Gon;Lim, Sung-Hun;Choi, Myong-Ho;Lee, Jong-Hwa;Han, Byoung-Sung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.107-110
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    • 2003
  • We have proposed a model to describe the current-voltage characteristics of fabricated devices using the Biot-Savart's law in order to develop superconducting flux flow transistors, The measured and calculated values, including induced voltage, transresistance and current gain were investigated in relation to the parallel flow of the vortices in a single microbridge. The predictions agreed very well with measured results.

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ELF Magnetic Field Calculation of High Speed Railway According to Condition of Train Operation (열차 운행조건에 따른 고속철도 주변의 극저주파 자기장 예측계산)

  • Myung, Sung-Ho;Lee, Jae-Bok;Kim, Jeom-Sik;Kim, Eung-Sik;Lee, Jong-Woo
    • Proceedings of the KIEE Conference
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    • pp.231-233
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    • 2001
  • 본 논문에서는 고속철도 급전계통 주변에서 여러가지 운전 조건하의 자계를 예측 계산하였다. 여기에서는 자계해석 방법으로 Biot Savart's law에 기반을 둔 해석식을 사용하였으며 대지 귀환회로를 계산과정에 포함하여 실제에 가까운 모델링을 하였다. 계산결과 열차 주변 지상 1m 부근의 플랫폼에서 자계의 크기그하였으며, 국제비전리방사보호위원회(ICNIRP)의 자기장 권고기준과 비교하여 평가하였다.

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