Regularization methods to assess the eddy current density inside conductive non-ferromagnetic media

2014 ◽  
Author(s):  
A. Lopes Ribeiro ◽  
H. G. Ramos ◽  
D. Pasadas ◽  
T. Rocha
Keyword(s):  
Current Density ◽  
Eddy Current ◽  
Regularization Methods ◽  
Eddy Current Density

scholarly journals SYNTHESIS OF EDDY CURRENT PROBES WITH VOLUMETRIC STRUCTURE OF THE EXCITATION SYSTEM, IMPLEMENTING HOMOGENEOUS SENSITIVITY IN THE TESTING ZONE

2021 ◽  
Vol 2021 (3) ◽  
pp. 10-18
Author(s):  
V.Ya. Halchenko ◽  
◽  
R.V. Trembovetska ◽  
V.V. Tychkov ◽  
◽  
...  
Keyword(s):  
Neural Networks ◽  
Current Density ◽  
Eddy Current ◽  
Dimensional Structure ◽  
Practical Implementation ◽  
Approximation Technique ◽  
Excitation System ◽  
Simultaneous Application ◽  
Testing Zone ◽  
Eddy Current Density

A method for nonlinear surrogate synthesis of surface eddy current probes with a volumetric structure of the excitation system was proposed. This method a priori provides a given uniform distribution of eddy current density in the testing object area where the measuring coil is located. The implementation of the task using modern metaeuristic stochastic algorithms for finding the global extremum was achieved. For the effective usage of such algorithms, taking into account the effect of velocity, metamodels of eddy current probe were preliminarily created. They were built using a productive approximation technique based on artificial radial-basis neural networks with a Gaussian activation function. Acceptable accuracy of metamodels was achieved due to the simultaneous application of the search area decomposition technologies and plural neural networks based on the techniques of associative machines with group methods for obtaining a solution. For metamodels creation a multidimensional computer experiment design with high homogeneity was used on the basis of the parameterless additive Rd-Kronecker sequence. Numerical experiments to determine the eddy current density distributions which formed by synthesized excitation structures were carried out. The advantages of using a three-dimensional structure excitation system in comparison with classical and planar ones in terms of increasing the width of the testing zone, which is characterized by uniform sensitivity, were shown. Examples of practical implementation of an excitation system with a volumetric structure for an surface eddy current probe are given. References 13, figures 8, table 1.

scholarly journals Eddy current density asymmetric distribution of damper bars in bulb tubular turbine generator

2017 ◽  
Vol 66 (3) ◽  
pp. 571-581
Author(s):  
Hongbo Qiu ◽  
Xiaobin Fan ◽  
Ran Yi ◽  
Jianqin Feng ◽  
Jie Wu ◽  
...  
Keyword(s):  
Current Density ◽  
Eddy Current ◽  
Optimization Design ◽  
Eddy Currents ◽  
Leeward Side ◽  
Asymmetric Distribution ◽  
Turbine Generator ◽  
Density Distributions ◽  
Transient Electromagnetic ◽  
Eddy Current Density

AbstractThe major reasons that cause the damage of damper bars in the leeward side are found in this paper. It provides a route for the structure optimization design of a hydro generator. Firstly, capacity of a 24 MW bulb tubular turbine generator is taken as an example in this paper. The transient electromagnetic field model is established, and the correctness of the model is verified by the comparison of experimental results and simulation data. Secondly, when the generator is operated at rated condition, the eddy current density distributions of damper bars are studied. And the asymmetric phenomenon of the eddy current density on damper bars is discovered. The change laws of the eddy currents in damper bars are determined through further analysis. Thirdly, through the study of eddy current distributions under different conditions, it is confirmed that the stator slots and armature reaction are the main factors to affect the asymmetric distribution of the eddy current in damper bars. Finally, the studies of the magnetic density distribution and theoretical analysis revealed the asymmetric distribution mechanism of eddy current density.

Noncontact measurement of eddy current density profiles

1995 ◽  
Vol 31 (13) ◽  
pp. 1049-1050
Author(s):  
P.N. Murgatroyd ◽  
H. McQuilliam
Keyword(s):  
Current Density ◽  
Eddy Current ◽  
Density Profiles ◽  
Noncontact Measurement ◽  
Eddy Current Density
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