Eddy currents in an infinite slab due to an elliptic current excitation

1991 ◽  
Vol 27 (5) ◽  
pp. 4328-4337 ◽  
Author(s):  
S.M. Panas ◽  
A.G. Papayiannakis
Keyword(s):  
Eddy Currents ◽  
Infinite Slab

THE ELECTROMAGNETIC FIELD DUE TO INDUCED CURRENTS IN A CONDUCTIVE SLAB OF FINITE DIMENSIONS

Geophysics ◽  
1950 ◽  
Vol 15 (4) ◽  
pp. 687-703 ◽  
Author(s):  
A. Belluigi
Keyword(s):  
Eddy Currents ◽  
Influence Diagrams ◽  
Electromagnetic Effect ◽  
Integral Formulas ◽  
First Case ◽  
Finite Slab ◽  
Infinite Slab ◽  
Vein Type ◽  
Induced Currents ◽  
Special Case

In conformity with what the author (1949a) presented briefly, the theory is developed of the electromagnetic eddy fields relative to a plane, thin, conducting slab with its plane perpendicular to the horizontal ground. The mineral slab is subjected to an alternating inducing magnetic field, paralleling the surface of the ground. After discussing the problem of the finite slab, the special case is considered of a semi‐infinite slab (Peters & Bardeen, 1930), e.g., the mineralized vein type, using existing formulas. With adequate development they can be used in the construction of theoretical graphs of the electromagnetic effects of the slab in which eddy currents are produced. The limiting dimensions, both of the dyke (first case of the finite slab), and the vein (second of the semi‐infinite slab case), act noticeably upon the measurable electromagnetic effect, and the influence diagrams characterize the slab‐shaped, conducting mineral. Therefore some fundamental characteristics on the surface and at depth of the slab and its extension in depth (thickness) can be deduced. The present paper consists of two sections, namely, (A) The theory of the finite, plane, and thin slab (dyke) and corresponding general formulas of magnetic influence. (B) A discussion of the special case of the semi‐infinite slab, or mineralized vein and of Peters‐Bardeen’s (1930) integral formulas, and their integration and illustration by means of graphs.

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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