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1

Verification of transformers windings models for FRA

Trela K., Gawrylczuk K.

Przegląd Elektrotechniczny

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2018

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R. 94, nr 10

49--52

EN

The aim of the article is to present the research carried out for verification of simulated transformer windings inductances. In the first stage of the research, the coil was wound on the distribution transformer core and the frequency response of this coil was measured. In the second stage, the computer model based on 3D Finite Elements Method (FEM) was prepared. Surveys indicate the need to assume equivalent core material properties in order to carry out the correct simulation. Presented research can be used for modelling the inductance of the winding in wide frequency range.

PL

Celem artykułu jest przedstawienie badań przeprowadzonych w celu weryfikacji symulowanych indukcyjności uzwojeń transformatorów. W pierwszym etapie badań cewka została nawinięta na rdzeń transformatora rozdzielczego oraz zmierzono jej odpowiedź częstotliwościową. W drugim etapie opracowano model komputerowy 3D oparty na metodzie elementów skończonych (MES). Przeprowadzone badania wskazują na konieczność stosowania zastępczych wartości parametrów materiału rdzenia w celu wykonania poprawnej symulacji. Prowadzone badania mogą być wykorzystane do modelowania indukcyjności uzwojenia w szerokim zakresie częstotliwości.

2

Enhanced Microwave Absorption of CNT Composites Mixing with Fe3O4 and Carbonyl Iron

Park J. H., Choi J., Lee K., Park J., Song J. K., Jeon E.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 3

1513--1516

EN

We fabricated two different kinds of composite materials for absorbing microwave in a frequency range of 2 to 18 GHz using coaxial airline and thru-reflect-line (TRL) method. The composite materials having carbon nanotube (CNT) with carbonyl iron (CI) or iron oxide (Fe3 O4 ) were fabricated by mixing each components. Magnetic properties were measured by SQUID equipment. Complex permittivity and complex permeability were also obtained by measuring S-parameters of the toroidal specimen dispersing CI/CNT and Fe3 O4 /CNT into the 50 weight percent (wt%) epoxy resin. The real permittivity was improved by mixing the CNT however, the real permeability was same as pure magnetic powders. The CI/CNT had a maximum value of real permittivity and real permeability, 11 and 1.4 at 10 GHz, respectively. The CNT composites can be adapted to the radar absorbing materials, band width 8-12 GHz.

3

Przenikalność magnetyczna zespolona taśm anizotropowych

Roman A., Gil A.

Prace Naukowe Akademii im. Jana Długosza w Częstochowie. Edukacja Techniczna i Informatyczna

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2008

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T. 3

49-57

EN

In the paper the frequency characteristics of complex permeability of amorphous material have been defined. The achieve this Polivanovs model has been used. Polivanov determined complex permeability by solving Laplace'a equation. Such a solution does not take into consideration skin effect. Therefore in the paper Helmholtz equation has been solved. Obtained results have been compared with Polivanovs ones.