scholarly journals Analysis of eddy-currents interaction with a flaw in a conductive plate

2005 ◽  
Vol 5 (2) ◽  
pp. 105-108 ◽  
Author(s):  
H. Bayani ◽  
I. Sasada
Keyword(s):  
Eddy Currents ◽  
Conductive Plate

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.

Determination of eddy current losses and hysteresis losses in magnetic circuits of electrical machines

2020 ◽  
pp. 54-58
Author(s):  
S. M. Plotnikov
Keyword(s):  
Eddy Current ◽  
Magnetization Reversal ◽  
Eddy Currents ◽  
Technical Problem ◽  
Electrical Machines ◽  
Eddy Current Losses ◽  
Hysteresis Losses ◽  
Magnetic Circuits ◽  
Core Losses ◽  
Reversal Frequency

The division of the total core losses in the electrical steel of the magnetic circuit into two components – losses dueto hysteresis and eddy currents – is a serious technical problem, the solution of which will effectively design and construct electrical machines with magnetic circuits having low magnetic losses. In this regard, an important parameter is the exponent α, with which the frequency of magnetization reversal is included in the total losses in steel. Theoretically, this indicator can take values from 1 to 2. Most authors take α equal to 1.3, which corresponds to the special case when the eddy current losses are three times higher than the hysteresis losses. In fact, for modern electrical steels, the opposite is true. To refine the index α, an attempt was made to separate the total core losses on the basis that the hysteresis component is proportional to the first degree of the magnetization reversal frequency, and the eddy current component is proportional to the second degree. In the article, the calculation formulas of these components are obtained, containing the values of the total losses measured in idling experiments at two different frequencies, and the ratio of these frequencies. It is shown that the rational frequency ratio is within 1.2. Presented the graphs and expressions to determine the exponent α depending on the measured no-load losses and the frequency of magnetization reversal.

Hidden Crack Detection with GMR Sensing of Magnetic Fields from Eddy Currents

2007 ◽  
Author(s):  
Ray T. Ko ◽  
Shamachary Sathish ◽  
Jeremy S. Knopp ◽  
Mark P. Blodgett
Keyword(s):  
Magnetic Fields ◽  
Crack Detection ◽  
Eddy Currents

scholarly journals Effect of the Temperature on the Magnetic and Energetic Properties of Soft Magnetic Composite Materials

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4400
Author(s):  
Luca Ferraris ◽  
Fausto Franchini ◽  
Emir Pošković ◽  
Marco Actis Grande ◽  
Róbert Bidulský
Keyword(s):  
Magnetic Materials ◽  
Eddy Currents ◽  
Electrical Machines ◽  
Soft Magnetic Materials ◽  
Magnetic Composite ◽  
Soft Magnetic ◽  
Soft Magnetic Composite ◽  
Magnetic Performance ◽  
Magnetic Circuits ◽  
Energetic Characterization

In recent years, innovative magnetic materials have been introduced in the field of electrical machines. In the ambit of soft magnetic materials, laminated steels guarantee good robustness and high magnetic performance but, in some high-frequency applications, can be replaced by Soft Magnetic Composite (SMC) materials. SMC materials allow us to reduce the eddy currents and to design innovative 3D magnetic circuits. In general, SMCs are characterized at room temperature, but as electrical machines operate at high temperature (around 100 °C), an investigation analysis of the temperature effect has been carried out on these materials; in particular, three SMC samples with different binder percentages and process parameters have been considered for magnetic and energetic characterization.

Porosity Quatification of Cast Aluminium Alloys on Machined Surfaces Using Metallography and Eddy-Currents

2015 ◽  
Vol 647 ◽  
pp. 188-194
Author(s):  
Břetislav Skrbek
Keyword(s):  
Surface Treatment ◽  
Aluminium Alloys ◽  
Eddy Currents ◽  
Initiation Site ◽  
Cast Aluminium ◽  
Strength And Ductility ◽  
Machined Surfaces

The porosity is unwanted phenomenon mostly that is tried to eliminate. The pores are initiation site of fatigue fractions usually, they worse strength and ductility of materials, quality of machined surfaces and their following surface treatment.

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