Closure on “A Wide-Band Lumped Circuit Model of Eddy Current Losses in a Coil With a Coaxial Insulation System and a Stranded Conductor”

2004 ◽  
Vol 19 (2) ◽  
pp. 903-903
Author(s):  
P. Holmberg ◽  
M. Leijon ◽  
T. Wass
Keyword(s):  
Eddy Current ◽  
Wide Band ◽  
Circuit Model ◽  
Insulation System ◽  
Eddy Current Losses ◽  
Lumped Circuit Model

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.

A nonlinear magnetic circuit model for periodic eddy current problems using T,ϕ-ϕ formulation

2017 ◽  
Vol 36 (3) ◽  
pp. 649-664 ◽  
Author(s):  
Rene Plasser ◽  
Gergely Koczka ◽  
Oszkár Bíró
Keyword(s):  
Eddy Current ◽  
Magnetic Circuit ◽  
Iteration Process ◽  
Equation System ◽  
Circuit Model ◽  
Computational Time ◽  
Combined Method ◽  
3D Fem ◽  
Content Type ◽  
Transformer Model

Purpose A transformer model is used as a benchmark for testing various methods to solve 3D nonlinear periodic eddy current problems. This paper aims to set up a nonlinear magnetic circuit problem to assess the solving procedure of the nonlinear equation system for determining the influence of various special techniques on the convergence of nonlinear iterations and hence the computational time. Design/methodology/approach Using the T,ϕ-ϕ formulation and the harmonic balance fixed-point approach, two techniques are investigated: the so-called “separate method” and the “combined method” for solving the equation system. When using the finite element method (FEM), the elapsed time for solving a problem is dominated by the conjugate gradient (CG) iteration process. The motivation for treating the equations of the voltage excitations separately from the rest of the equation system is to achieve a better-conditioned matrix system to determine the field quantities and hence a faster convergence of the CG process. Findings In fact, both methods are suitable for nonlinear computation, and for comparing the final results, the methods are equally good. Applying the combined method, the number of iterations to be executed to achieve a meaningful result is considerably less than using the separated method. Originality/value To facilitate a quick analysis, a simplified magnetic circuit model of the 3D problem was generated to assess how the different ways of solutions will affect the full 3D solving process. This investigation of a simple magnetic circuit problem to evaluate the benefits of computational methods provides the basis for considering this formulation in a 3D-FEM code for further investigation.

Losses in ac of BSCCO-2223 superconducting monofilament and multifilament tapes at power frequencies

1997 ◽  
Vol 12 (11) ◽  
pp. 3085-3089
Author(s):  
S. Mench ◽  
M. Lelovic ◽  
T. Deis ◽  
N. G. Eror ◽  
U. Balachandran ◽  
...  
Keyword(s):  
Eddy Current ◽  
Anisotropy Field ◽  
Magnetic Losses ◽  
Field Orientation ◽  
Eddy Current Losses ◽  
Order Of Magnitude

The ac magnetic losses at power frequencies (60 Hz) were investigated for mono- and multifilament Ag-sheathed (Bi, Pb)2Sr2Ca2Cu3Oy (BSCCO-2223) tapes with similar Ic values at 77 K. The multifilament sample exhibited higher losses than the monofilament under the same conditions. Loss peaks are discussed in terms of intergranular, intragranular, and eddy current losses. Because of BSCCO's anisotropy, field orientation has a large effect on the magnitude of these peaks, even at relatively small angles. Losses for fields applied parallel to the c-axis of the textured BSCCO grains are larger by over an order of magnitude than those applied perpendicular.

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