Modeling of Leakage Magnetic Field of Electric Machines Using Blocks With Magnetizations for Design of Magnetically Shielded Room

2017 ◽  
Vol 53 (6) ◽  
pp. 1-4
Author(s):  
Kazuhiro Muramatsu ◽  
Yanhui Gao ◽  
Yusuke Moriyama ◽  
Hiroshi Dozono ◽  
Takaaki Nishino ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electric Machines ◽  
Leakage Magnetic Field ◽  
Magnetically Shielded Room

Digital phase analysis in interference electron microscopy

1988 ◽  
Vol 46 ◽  
pp. 842-843
Author(s):  
S. Hasegawa ◽  
T. Kawasaki ◽  
J. Endo ◽  
M. Futamoto ◽  
A. Tonomura
Keyword(s):  
Magnetic Field ◽  
Electron Microscopy ◽  
Phase Distribution ◽  
Magnetic Recording Media ◽  
Electron Wave ◽  
Vector Potentials ◽  
Weak Magnetic Fields ◽  
Leakage Magnetic Field ◽  
Optical Reconstruction ◽  
Processing Techniques

Interference electron microscopy enables us to record the phase distribution of an electron wave on a hologram. The distribution is visualized as a fringe pattern in a micrograph by optical reconstruction. The phase is affected by electromagnetic potentials; scalar and vector potentials. Therefore, the electric and magnetic field can be reduced from the recorded phase. This study analyzes a leakage magnetic field from CoCr perpendicular magnetic recording media. Since one contour fringe interval corresponds to a magnetic flux of Φo(=h/e=4x10-15Wb), we can quantitatively measure the field by counting the number of finges. Moreover, by using phase-difference amplification techniques, the sensitivity for magnetic field detection can be improved by a factor of 30, which allows the drawing of a Φo/30 fringe. This sensitivity, however, is insufficient for quantitative analysis of very weak magnetic fields such as high-density magnetic recordings. For this reason we have adopted “fringe scanning interferometry” using digital image processing techniques at the optical reconstruction stage. This method enables us to obtain subfringe information recorded in the interference pattern.

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.

Математическое описание и анализ сигнала виброиндукционного преобразователя при воздействии нормальной составляющей магнитных потоков рассеяния над дефектным участком

2021 ◽  
Vol 7 ◽  
pp. 19-27
Author(s):  
Ю.Л. Николаев ◽  
П.Н. Шкатов ◽  
Э.Ф. Ахметшина ◽  
А.А. Саморуков
Keyword(s):  
Magnetic Field ◽  
Mathematical Model ◽  
Initial Data ◽  
Vibration Frequency ◽  
Magnetic Field Intensity ◽  
Theoretical Research ◽  
Leakage Magnetic Field ◽  
Induction Transducer ◽  
Experimental Researches ◽  
Defective Area

Theoretical and experimental researches of vibration-induction transducer (VIT) outlet signal formed during exposure to normal leakage magnetic field intensity component Hn over the defective area were carried out. Theoretical research is based on an assumption that VIT signal is a trigonometric series that is limited by first five harmonics. As initial data for mathematical model creation, well-known conformities for Hn distribution over the defective area were used. Based on acquired mathematical model conformities of VIT signal harmonical composition permutation during its movement over the defective area with varying amplitudes and vibration frequency were found. Theoretical research results were proven experimentally. Moreover, additional possibilities of this way of magnetic testing are shown in comparison with conventional ones.

Generic Models of Electric Machine Applications in Hybrid Electric Vehicles Power Train Simulations

2013 ◽  
pp. 95-150
Keyword(s):  
Magnetic Field ◽  
Permanent Magnet ◽  
Rotational Speed ◽  
Electric Machines ◽  
Simulation Studies ◽  
Permanent Magnet Motors ◽  
Power Train ◽  
Field Weakening ◽  
Generic Models ◽  
Hybrid Power

Chapter 4 presents an approach to obtain the power simulation model of electric machines that would be practically useful in hybrid power train simulation studies. The induction motor (AC) and the permanent magnet motor’s (PM) mathematical dynamic models are based on the necessary and fundamental knowledge conveyed in the previous chapter. These generic models are here adapted to the hybrid power train requirements, while the mechanical characteristics of the vehicle’s driving system are relegated to the background. The vector field oriented control of induction and permanent magnet motors is applied in the conducted mathematical modeling. The influence of the controlled voltage frequency is discussed as well. In the case of permanent magnet motors, the adjusted method of magnetic field weakening is very important during pulse modulation (PWM) control. The chapter presents the model of synchronous permanent motor magnetic field weakening. The basic simulation studies’ results dedicated especially to the above-mentioned electric motors are included. One of the targets of these simulations is the determination of these electric machines’ static characteristics (motor’s map) as the function: output mechanical torque versus the motors’ shaft rotational speed. This feature is indicated as the map of electric machines connected with its efficiency in a four quarterly operation (4Q), which means the operation of the motor/generator mode in two directions of the shaft rotational speed, which appears very useful in practice.

scholarly journals Prediction of Eddy Current Losses in Cooling Tubes of Direct Cooled Windings in Electric Machines

Mathematics ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 1096 ◽  
Author(s):  
Mohamed Nabil Fathy Ibrahim ◽  
Peter Sergeant
Keyword(s):  
Magnetic Field ◽  
Finite Element ◽  
Eddy Current ◽  
Electric Machines ◽  
Iron Core ◽  
Commercial Software ◽  
Eddy Current Losses ◽  
Switched Reluctance ◽  
Element Simulation ◽  
Core Losses

The direct coil cooling method is one of the existing cooling techniques for electric machines with concentrated windings, in which cooling tubes of conductive material are inserted between the windings. In such cases, eddy current losses are induced in those cooling tubes because of the time variant magnetic field. To compute the cooling tubes losses, either a transient finite element simulation (mostly based on commercial software), or a full analytical method, which is more complex to be constructed, is required. Instead, this paper proposes a simple and an accurate combined semi-analytical-finite element method to calculate the losses of electric machines having cooling tubes. The 2D magnetostatic solution of the magnetic field is obtained e.g., using the free package “FEMM”. Then, the eddy current losses in the tubes are computed using simple analytical equations. In addition, the iron core losses could be obtained. In order to validate the proposed method, two cases are investigated. In Case 1, a six-toothed stator of a switched reluctance machine (SRM), without rotor, is employed in which six cooling tubes are used while in Case 2 a complete rotating SRM is studied. The proposed method is validated by a 2D transient simulation in the commercial software “ANSYS Maxwell” and also by experimental measurements. Evidently, the proposed method is simple and fast to be constructed and it is almost free of cost.

A Study on the Magnetic Distribution of Nd-Fe-B Permanent Magnets in Pipeline in Line Inspection Tool

2018 ◽  
Author(s):  
Pan Song ◽  
Xiaoying Tang ◽  
ShaoJun Wang ◽  
Bin Ren ◽  
Yantian Zuo ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Permanent Magnets ◽  
Oil And Gas ◽  
Field Performance ◽  
Magnetic Intensity ◽  
Leakage Magnetic Field ◽  
Element Simulation ◽  
Pressure Pipeline ◽  
Nondestructive Testing Method

The pressure pipeline in line inspection technology is the most effective nondestructive testing method to detect the quality of buried oil and gas pipelines at present. In line inspection tool usually uses magnetic flux leakage (MFL) technology to detect the change of leakage magnetic field to detect pipeline defects. Permanent magnets magnetize the wall of the pipeline as an excitation. During the detection process, the magnetic field performance of permanent magnets is required to be high. At the same time, the magnetic performance of the permanent magnet in the magnetic cleaning pipe also determine the cleaning effect inside the pipeline. In this paper, the magnetic distribution of permanent magnets is studied and the Nd-Fe-B permanent magnets with the best magnetic properties are taken as the objects. The finite element simulation is used to optimize the shape of the permanent magnets with better magnetic distribution, and the magnetic intensity factors of the preferred cylindrical permanent magnets are analyzed. In addition, three experiments of the influence of temperature, the influence of the ferromagnetic combination, and the influence of the environment medium are conducted. As a result, the relationship between the magnetic intensity of the Nd-Fe-B permanent magnets and the factors is obtained. The conclusion is of great significance to the design and research of permanent magnetic circuit in line inspection magnetization device.

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