scholarly journals Extraction of nonlinear characteristics from eddy current magnetic field of Al-alloy weld and their classification

2014 ◽  
Vol 63 (13) ◽  
pp. 134103
Author(s):  
Gao Peng ◽  
Wang Chao ◽  
Zhi Ya ◽  
Li Yang ◽  
Wang Li-Bin ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Eddy Current ◽  
Al Alloy ◽  
Nonlinear Characteristics ◽  
Current Magnetic Field ◽  
Alloy Weld

Finite Element Analysis of AMB Eddy-Current Loss in HTR-PM Primary Helium Circulator

2018 ◽  
Author(s):  
Jinpeng Yu ◽  
Yan Zhou ◽  
Mo Ni ◽  
Guojun Yang ◽  
Lei Zhao
Keyword(s):  
Magnetic Field ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Eddy Current ◽  
Electromagnetic Force ◽  
Eddy Current Loss ◽  
Element Analysis ◽  
Current Loss ◽  
Resistance Torque ◽  
Current Magnetic Field

In the active magnetic bearing (AMB) system, the eddy current is generated during the rotation of the rotor, which brings about the AMB loss and eddy-current magnetic field. The eddy-current magnetic field will reduce the electromagnetic force and generate the resistance torque of the AMB. Basing on the AMB of the Primary Helium Circulator (PHC) in HTR-PM, two-dimensional (2D) and three-dimensional (3D) AMB models are built and analyzed with finite element analysis (FEA) in maxwell. The 2D FEA shows that the eddy-current loss and the resistance torque increase as the rotor speed increases, and the eddy-current magnetic field will affect the air-gap magnetic field and reduce the electromagnetic force. The 3D FEA shows that dividing the rotor in insulate sheets can reduce the eddy-current loss. The loss and the sheets thickness have a linear relationship, which is different from the theoretical analysis.

scholarly journals Simulations and Measurements of Eddy Current Magnetic Signatures

2018 ◽  
Vol 215 (4) ◽  
pp. 77-102
Author(s):  
Paweł Polański ◽  
Franciszek Szarkowski
Keyword(s):  
Magnetic Field ◽  
Eddy Current ◽  
Eddy Currents ◽  
Rate Of Change ◽  
Scale Model ◽  
Stray Field ◽  
Physical Scale ◽  
Magnetic Signature ◽  
Magnetic Signatures ◽  
Current Magnetic Field

Abstract Eddy current magnetic signature is, together with magnetization of ferromagnetic hull, mechanisms and devices on board, corrosion related and stray field sources one of the main sources of ship’s magnetic signature. Due to roll, pitch and yaw of the ship in external magnetic field, eddy currents are induced in conducting materials on board ship, mainly in conducting hull. Flow of those currents is a source of magnetic field around a ship. Principal eddy current component is related to roll movement as it depends on rate of change of external field which is the highest for roll. Induced currents have both in-phase and quadrature components. Magnitude of the eddy current magnetic field can have significant effect on total magnetic field signature after degaussing for ships such as mine sweepers and mine hunters. Paper presents calculations and simulations as well as measurements of model and physical scale model made of low magnetic steel performed in Maritime Technology Center. Contribution of eddy current magnetic field in total field in low roll frequencies has been estimated.

Physical Mechanism of Eddy Current Demagnetizing Effect for Eddy Current Brake

2016 ◽  
Vol 13 (10) ◽  
pp. 6810-6822
Author(s):  
Ren He ◽  
Donghai Hu
Keyword(s):  
Magnetic Field ◽  
Eddy Current ◽  
Performance Test ◽  
Physical Mechanism ◽  
Theoretical Calculations ◽  
Air Gap ◽  
Moving Conductor ◽  
Air Gap Magnetic Field ◽  
Current Magnetic Field ◽  
Excitation Magnetic Field

This article researches both the mathematical relation between the braking force of eddy current brake and the speed of the moving conductor and the relationship between the average air-gap flux density and the velocity of the moving conductor respectively which result in the ambiguity of the physical mechanism of eddy current demagnetizing effect. The theoretical methods for obtaining the distribution of the excitation magnetic field, the eddy current magnetic field and the air gap magnetic field of eddy current brake were presented. Then the impacts of the excitation magnetic field and eddy current magnetic field on the distribution of air gap magnetic field were got through contrastive analysis and then the physical mechanism of eddy current demagnetizing effect is obtained. Finally, the influence of the eddy current demagnetizing effect on the design and control of eddy current brake was discussed in depth. The correctness of these theoretical calculations was validated by experiments on the retarder synthetic performance test bench or the finite element numerical calculation.

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