Comparison of alternative formulations of 3-dimensional magnetic-field and eddy-current problems at power frequencies

1980 ◽  
Vol 127 (5) ◽  
pp. 331
Author(s):  
M.L. Brown
Keyword(s):  
Magnetic Field ◽  
Eddy Current ◽  
3 Dimensional

STUDY OF PHASE PROPAGATION IN SUPERCONDUCTING ALUMINUM BY ULTRASONIC ATTENUATION MEASUREMENTS

1959 ◽  
Vol 37 (5) ◽  
pp. 614-618 ◽  
Author(s):  
K. L. Chopra ◽  
T. S. Hutchison
Keyword(s):  
Magnetic Field ◽  
Eddy Current ◽  
Ultrasonic Attenuation ◽  
Cylindrical Specimen ◽  
Current Theory ◽  
Superconducting Phase ◽  
Rate Of Change ◽  
Time Rate ◽  
Phase Propagation ◽  
The Magnetic Field

The phase propagation in superconducting aluminum has been studied by measuring the time rate of change of ultrasonic attenuation. The time taken for the destruction of the superconducting phase in a cylindrical specimen, by means of a magnetic field, H, greater than the critical field, Hc, is approximately proportional to{H/(H–Hc)} in agreement with eddy-current theory. In the converse case, where the superconducting phase is restored by switching off the magnetic field H (>Hc), the total time taken is nearly independent of the temperature (or Hc) as well as H. The superconducting phase grows at a non-uniform volume rate which is considerably less than the uniform rate of collapse.

Effects of a High Magnetic Field on the Growth of 3-Dimensional Silver Dendrites

2004 ◽  
Vol 77 (2) ◽  
pp. 275-279 ◽  
Author(s):  
Akio Katsuki ◽  
Ichiro Uechi ◽  
Yoshifumi Tanimoto
Keyword(s):  
Magnetic Field ◽  
High Magnetic Field ◽  
3 Dimensional ◽  
Silver Dendrites

Eddy Current Loss and Shielding Research of the Tank in Power Transformer

2012 ◽  
Vol 468-471 ◽  
pp. 1086-1089 ◽  
Author(s):  
Yong Ming Xu ◽  
Chao Du ◽  
Da Wei Meng
Keyword(s):  
Magnetic Field ◽  
Eddy Current ◽  
Power Transformer ◽  
Element Model ◽  
Eddy Current Loss ◽  
Calculation Model ◽  
Ultrahigh Pressure ◽  
Tank Wall ◽  
Current Loss ◽  
Leakage Magnetic Field

The problem about the eddy current loss which is caused by leakage magnetic field in ultrahigh pressure large capacity power transformer is becoming more extrusive. It is very significant to research the power transformer leakage magnetic field and eddy current loss on the tank wall thoroughly and accurately. 3D finite element model of power transformer leakage magnetic field and eddy current loss is established in this paper, the eddy current loss on the tank wall is calculated and the distribution is analyzed. For the eddy current loss could be reduced by magnetic shielding, new calculation model are established respectively, then eddy current loss on tank wall could be got with shielding. The best size and location of the shielding could be analyzed after changing the height of the shielding, which provided the important evidence to reduce tank wall eddy current loss effectively. The calculating methods have been proved to be accuracy after experiment.

Quantitative Research on Cracks in Pipe Based on Magnetic Field Response Method of Eddy Current Testing

2021 ◽  
Vol 36 (1) ◽  
pp. 99-107
Author(s):  
Feng Jiang ◽  
Shulin Liu ◽  
Li Tao
Keyword(s):  
Magnetic Field ◽  
Eddy Current ◽  
Quantitative Research ◽  
Three Dimensional ◽  
Impedance Analysis ◽  
Eddy Current Testing ◽  
Element Analysis ◽  
Defect Parameter ◽  
Current Testing ◽  
The Magnetic Field

The quantitative evaluation of defects in eddy current testing is of great significance. Impedance analysis, as a traditional method, is adopted to determine defects in the conductor, however, it is not able to depict the shape, size and location of defects quantitatively. In order to obtain more obvious characteristic quantities and improve the ability of eddy current testing to detect defects, the study of cracks in metal pipes is carried out by utilizing the analysis method of three-dimensional magnetic field in present paper. The magnetic field components in the space near the crack are calculated numerically by using finite element analysis. The simulation results confirm that the monitoring of the crack change can be achieved by measuring the magnetic field at the arrangement positions. Besides, the quantitative relationships between the shape, length of the crack and the magnetic field components around the metal pipe are obtained. The results show that the axial and radial magnetic induction intensities are affected more significantly by the cross-section area of the crack. Bz demonstrates obvious advantages in analyzing quantitatively crack circumference length. Therefore, the response signal in the three-dimensional direction of the magnetic field gets to intuitively reflect the change of the defect parameter, which proves the effectiveness and practicability of this method.

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