Analysis of three-dimensional magnetic field inducing eddy currents-on the nature of scalar potential

1983 ◽  
Vol 103 (6) ◽  
pp. 17-25 ◽  
Author(s):  
Shinya Hasebe ◽  
Yoshio Kano
Keyword(s):  
Magnetic Field ◽  
Eddy Currents ◽  
Scalar Potential ◽  
Three Dimensional

scholarly journals General 3D Analytical Method for Eddy-Current Coupling with Halbach Magnet Arrays Based on Magnetic Scalar Potential and H-Functions

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8458
Author(s):  
Xiaoquan Lu ◽  
Xinyi He ◽  
Ping Jin ◽  
Qifeng Huang ◽  
Shihai Yang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Eddy Current ◽  
Analytical Method ◽  
Eddy Currents ◽  
Scalar Potential ◽  
Fourier Decomposition ◽  
Field Distributions ◽  
Current Coupling ◽  
Current Calculation ◽  
Laplacian Equations

Rapid and accurate eddy-current calculation is necessary to analyze eddy-current couplings (ECCs). This paper presents a general 3D analytical method for calculating the magnetic field distributions, eddy currents, and torques of ECCs with different Halbach magnet arrays. By using Fourier decomposition, the magnetization components of Halbach magnet arrays are determined. Then, with a group of H-formulations in the conductor region and Laplacian equations with magnetic scalar potential in the others, analytical magnetic field distributions are predicted and verified by 3D finite element models. Based on Ohm’s law for moving conductors, eddy-current distributions and torques are obtained at different speeds. Finally, the Halbach magnet arrays with different segments are optimized to enhance the fundamental amplitude and reduce the harmonic contents of air-gap flux densities. The proposed method shows its correctness and validation in analyzing and optimizing ECCs with Halbach magnet arrays.

Frequency and Time Response of Power Plant Grounding System Exposed to Lightning Strike

2016 ◽  
Vol 6 (2) ◽  
pp. 512
Author(s):  
Srete N Nikolovski ◽  
Zoran Baus ◽  
Goran Knežević
Keyword(s):  
Magnetic Field ◽  
Power Plant ◽  
Scalar Potential ◽  
Three Dimensional ◽  
Lightning Strike ◽  
Fast Fourier Transformation ◽  
Theory Approach ◽  
Grounding System ◽  
Lightning Current ◽  
Electric And Magnetic Field

This paper examines the frequency response of power plant grounding system exposed to the lightning current. Large amount of current generated by the stroke flow in the grounding system of power plant and dissipate in the soil.  The electric and magnetic field generated by such high voltages and currents may cause damage of equipment and may be dangerous for the personnel in power plant.  For the every given frequency obtained using Fast Fourier Transformation (FFT) of lightning current impulse, electromagnetic field theory approach is used to solve Maxell’s equation and compute scalar potential, electric and magnetic field. Also, the influence of the point in which lightning current is diffused in the grounding system is presented. Three dimensional plots of spatial distribution of scalar potential, electric and magnetic field are presented. The time domain response of scalar potential, electric and magnetic field on one profile is also presented.

3D Analytical model of drag and lift force for a conductive plate moving above a Halbach magnet array

2017 ◽  
Vol 40 (12) ◽  
pp. 3515-3524 ◽  
Author(s):  
Shi Tongyu ◽  
Wang Dazhi
Keyword(s):  
Magnetic Field ◽  
Analytical Model ◽  
Eddy Current ◽  
Eddy Currents ◽  
Magnetic Levitation ◽  
Scalar Potential ◽  
Air Gap ◽  
Steady State Condition ◽  
Conductive Plate ◽  
Drag And Lift

When a conductive plate moves above a Halbach magnetic source, a magnetic field will be created in the air gap. This field induces eddy currents in the plate and creates drag and lift forces simultaneously. This phenomenon may be applied into eddy current brakes, couplings or magnetic levitation systems. In this paper, by utilizing the derived analytical field solutions of the Maxwell equations with magnetic scalar potential and magnetic field strength, the 3D lift and drag forces, and the flux density distribution in the air gap are predicted and analysed in the steady-state condition. Calculation results produced by analytical model are compared with those from the 3D finite element method. A prototype of the disk-type permanent magnetic eddy-current coupling has been manufactured to validate the accuracy of the 3D analytical model. The results confirm that, compared with 2D analytical model from the papers that had already published, the results calculated by the 3D analytical model have a higher accuracy in performance analysis. Finally, the characteristics of different kinds of magnet arrays are compared based on the proposed model, and several main problems are analysed and discussed.

scholarly journals Frequency and Time Response of Power Plant Grounding System Exposed to Lightning Strike

2016 ◽  
Vol 6 (2) ◽  
pp. 512
Author(s):  
Srete N Nikolovski ◽  
Zoran Baus ◽  
Goran Knežević
Keyword(s):  
Magnetic Field ◽  
Power Plant ◽  
Scalar Potential ◽  
Three Dimensional ◽  
Lightning Strike ◽  
Fast Fourier Transformation ◽  
Theory Approach ◽  
Grounding System ◽  
Lightning Current ◽  
Electric And Magnetic Field

This paper examines the frequency response of power plant grounding system exposed to the lightning current. Large amount of current generated by the stroke flow in the grounding system of power plant and dissipate in the soil.  The electric and magnetic field generated by such high voltages and currents may cause damage of equipment and may be dangerous for the personnel in power plant.  For the every given frequency obtained using Fast Fourier Transformation (FFT) of lightning current impulse, electromagnetic field theory approach is used to solve Maxell’s equation and compute scalar potential, electric and magnetic field. Also, the influence of the point in which lightning current is diffused in the grounding system is presented. Three dimensional plots of spatial distribution of scalar potential, electric and magnetic field are presented. The time domain response of scalar potential, electric and magnetic field on one profile is also presented.

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