scholarly journals The Magnetic Field of a Current Loop Encircling an Axisymmetric Iron Core

1976 ◽  
Vol 29 (2) ◽  
pp. 1 ◽  
Author(s):  
RL Dewar
Keyword(s):  
Convergent Series ◽  
Numerical Results ◽  
Current Loop ◽  
Iron Core ◽  
Air Gaps ◽  
The Core ◽  
Asymptotic Expressions ◽  
Transformer Core ◽  
A Current ◽  
Straight Rod

The effect of an iron transformer core on the field of a current loop is examined for two models of the core: (1) An infinite straight rod of high permeability aligned along the axis of symmetry, for which asymptotic expressions for the effect of the core are obtained and compared with numerical results. (2) A rectangular toroidal iron casing surrounding the loop. The latter model is more realistic because a return path is provided for the flux. For this model, the effect of air gaps is considered, and rapidly convergent series are obtained and numerical results are given. The significance of these results for tokamak equilibrium is indicated.

scholarly journals Acoustic Panels Made of Paper Sludge and Clay Composites

2021 ◽  
Vol 13 (2) ◽  
pp. 637
Author(s):  
Tomas Astrauskas ◽  
Tomas Januševičius ◽  
Raimondas Grubliauskas
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Composite Panel ◽  
Sound Absorption Coefficient ◽  
Core Material ◽  
Paper Sludge ◽  
Frequency Range ◽  
Absorption Properties ◽  
Air Gaps ◽  
The Core

Studies on recycled materials emerged during recent years. This paper investigates samples’ sound absorption properties for panels fabricated of a mixture of paper sludge (PS) and clay mixture. PS was the core material. The sound absorption was measured. We also consider the influence of an air gap between panels and rigid backing. Different air gaps (50, 100, 150, 200 mm) simulate existing acoustic panel systems. Finally, the PS and clay composite panel sound absorption coefficients are compared to those for a typical commercial absorptive ceiling panel. The average sound absorption coefficient of PS-clay composite panels (αavg. in the frequency range from 250 to 1600 Hz) was up to 0.55. The resulting average sound absorption coefficient of panels made of recycled (but unfinished) materials is even somewhat higher than for the finished commercial (finished) acoustic panel (αavg. = 0.51).

scholarly journals Core Stress Analysis of Amorphous Alloy Transformer for Rail Transit under Different Working Conditions

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 164
Author(s):  
Jianwei Shao ◽  
Cuidong Xu ◽  
Ka Wai Eric Cheng
Keyword(s):  
Amorphous Alloy ◽  
Working Conditions ◽  
Short Circuit ◽  
Element Model ◽  
Operating Conditions ◽  
Iron Core ◽  
Rail Transit ◽  
Transit System ◽  
The Core ◽  
Distribution Transformers

The rail transit system is a large electric vehicle system that is strongly dependent on the energy technologies of the power system. The use of new energy-saving amorphous alloy transformers can not only reduce the loss of rail transit power, but also help alleviate the power shortage situation and electromagnetic emissions. The application of the transformer in the field of rail transit is limited by the problem that amorphous alloy is prone to debris. this paper studied the stress conditions of amorphous alloy transformer cores under different working conditions and determined that the location where the core is prone to fragmentation, which is the key problem of smoothly integrating amorphous alloy distribution transformers on rail transit power supply systems. In this study, we investigate the changes in the electromagnetic field and stress of the amorphous alloy transformer core under different operating conditions. The finite element model of an amorphous alloy transformer is established and verified. The simulation results of the magnetic field and stress of the core under different working conditions are given. The no-load current and no-load loss are simulated and compared with the actual experimental data to verify practicability of amorphous alloy transformers. The biggest influence on the iron core is the overload state and the maximum value is higher than the core stress during short circuit. The core strain caused by the side-phase short circuit is larger than the middle-phase short circuit.

scholarly journals Mathematical modeling and harmonic analysis of SISFCL

2017 ◽  
Vol 36 (1) ◽  
pp. 258-270
Author(s):  
Debraj Sarkar ◽  
Debabrata Roy ◽  
Amalendu Bikash Choudhury ◽  
Sotoshi Yamada
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Harmonic Analysis ◽  
Voltage Drop ◽  
Element Model ◽  
Iron Core ◽  
Content Type ◽  
Hysteresis Characteristic ◽  
The Core ◽  
The Mathematical Model

Purpose A saturated iron core superconducting fault current limiter (SISFCL) has an important role to play in the present-day power system, providing effective protection against electrical faults and thus ensuring an uninterrupted supply of electricity to the consumers. Previous mathematical models developed to describe the SISFCL use a simple flux density-magnetic field intensity curve representing the ferromagnetic core. As the magnetic state of the core affects the efficient working of the device, this paper aims to present a novel approach in the mathematical modeling of the device with the inclusion of hysteresis. Design/methodology/approach The Jiles–Atherton’s hysteresis model is utilized to develop the mathematical model of the limiter. The model is numerically solved using MATLAB. To support the validity of model, finite element model (FEM) with similar specifications was simulated. Findings Response of the limiter based on the developed mathematical model is in close agreement with the FEM simulations. To illustrate the effect of the hysteresis, the responses are compared by using three different hysteresis characteristics. Harmonic analysis is performed and comparison is carried out utilizing fast Fourier transform and continuous wavelet transform. It is observed that the core with narrower hysteresis characteristic not only produces a better current suppression but also creates a higher voltage drop across the DC source. It also injects more harmonics in the system under fault condition. Originality/value Inclusion of hysteresis in the mathematical model presents a more realistic approach in the transient analysis of the device. The paper provides an essential insight into the effect of the core hysteresis characteristic on the device performance.

Structure of the near zone of a current-loop antenna in a magnetoactive plasma

1988 ◽  
Vol 31 (4) ◽  
pp. 299-308 ◽  
Author(s):  
V. I. Karpman ◽  
A. I. Osin ◽  
O. F. Pogrebnyak
Keyword(s):  
Magnetoactive Plasma ◽  
Loop Antenna ◽  
Current Loop ◽  
Near Zone ◽  
A Current

Transient fields of a current loop source above a layered earth

Geophysics ◽  
1982 ◽  
Vol 47 (7) ◽  
pp. 1068-1077 ◽  
Author(s):  
G. M. Hoversten ◽  
H. F. Morrison
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Electric Fields ◽  
Current Loop ◽  
Wave Form ◽  
Sign Reversal ◽  
Circular Loop ◽  
Single Ring ◽  
Smoke Ring ◽  
A Current

The electric field induced within four layered models by a repetitive current wave form in a circular loop transmitter is presented along with the resulting magnetic fields observed on the surface. The behavior of the induced electric field as a function of time explains the observed sign reversal of the vertical magnetic field on the surface. In addition, the differences between magnetic field responses for different models are explained by the behavior of the induced electric fields. The pattern of the induced electric field is shown to be that of a single “smoke ring,” as described by Nabighian (1979), which is distorted by layering but which remains a single ring system rather than forming separate smoke rings in each layer.

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