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Analysis of varnish composites properties in the course of moisture
Novák, Petr ; Frk, Martin (referee) ; Rozsívalová, Zdenka (advisor)
The presented bachelor´s work deals with preparation of micronized mica filled varnish sauples. At the same time the temperature and relative humidity influence on the electrical properties of composite material by dielectric relaxation spectroscopy method are monitoring. The composite material consists of epoxide varnish TSA 220S, which is modified with different mass percentage of micronized mica. The results of this project are frequency dependencies of real and imaginary parts of complex permitivity with the environmental temperatures and humidities parameters of varnish components.
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Study of electrical stress of slot insulations
Jabůrek, Ladislav ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This bachelor works deals with electrical effort problems of dielectric materials. The general aim is study of impact alternating electric field of great effort on slot insulation Nomex-Kapton-Nomex. Measurement of loss is realised by dielectric relaxation spectroscopy in frequency domain method. The another aim is apprise of electrical aeging, its causes and incidence on materials. Works deals below dielectric relaxation spectroscopy in time domain and frequency domain, fundamental effect in dielectric and measurement values coherent with electrical aeging.
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Dielectric properties of liquid insulators
Jahn, Michal ; Starý, Jiří (referee) ; Špinka, Jiří (advisor)
This master‘s thesis deals with measurement of liquid dielectric materials (insulators). Above all, it is the different kinds of clean and drinking water, but also transformer oils. There was done theoretical information retrieval about the given topic in this project and on the basis of theory there were realized the relevant measurements of selected properties of liquid dielectric, such as permittivity, capacitance, loss number, conductivity, but also temperature dependence of these parameters. The measurements were realized with the help of product manufactured at the faculty FEKT VUT and with the help of measuring system AGILENT 16452A. The measured results were evaluated, graphically processed and compared.
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Influence of the Temperature on the Dielectric properties epoxy with ground mica
Ráček, Tomáš ; Havlíček, Svatopluk (referee) ; Polsterová, Helena (advisor)
The paper is focused on theoretical analysis of the basic characteristics of dielectrics, especially on the examination of these qualities at samples of epoxy sealing compound filled with powder mica, and their dependance on the temperature and the content of filling in the material. The measured quantities are inner resistivity, relative permitivity, and loss factor. The paper also deals with the sensitivity of the material to humidity, and through the influence of humidity to the other measured quantities.
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Influence of filler particles size on parts of complex permittivity of composite
Mohyla, Petr ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This project deals with calculation parts of complex permittivity varnish samples which is filled by ground mica with variety size of particles. Opening of this project deals with theory of dielectric and effects in dielectric. Following topic is theory of compounds and expressions in composite systems. In practical part of work is include method which was use to make varnish samples, their temperature stress and whole results of measurement. In the end of work is influence of filler particles each filler types to dielectric material and including coefficient which include size of filler particles to suitable mathematical expression.
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Complex permittivity measurement of materials at microwave frequencies
Polák, Radek ; Hertl, Ivo (referee) ; Láčík, Jaroslav (advisor)
This article describes some methods of measuring complex permitivity in milimeter – wave band, their characteristics, anvatages and disadvantages. Discused are here the reasons for their use in the construction of work place. On the basis these reasons is chosen the best method for practical measurement. That is cavity resonant method. Article contain description of designed measurement system. Whitch is verified by computer simulating of developed model in HFSS Ansoft. Text contain also result of simulations and execute computing of comlex permittivity and tangent loss. In Conclusion is desribed results of practical permittivity measure with realized measurement system.
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Properties of filled micro- and nanoparticles varnish composites
Novák, Petr ; Frk, Martin (referee) ; Rozsívalová, Zdenka (advisor)
The presented work deals with preparation of test samples filled microparticles of mica and nanoparticles of silicon dioxide (SiO2). Monitors the impact of climatic conditions and filler on electrical properties of composite materials. Electrical properties of composite materials are measured by dielectric relaxation spectroscopy. Test samples influence of epoxide resin TSA 220S and polyester resin DOLPHON XL 2102. Varnishes are modified with different weight percentage of nanoparticles of silicon dioxide, or micronized mica. The results of this project are frequency dependencies of parts of complex permittivity and their evaluation.
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Dielectric properties of epoxy with nano particle
Ráček, Tomáš ; Rozsívalová, Zdenka (referee) ; Polsterová, Helena (advisor)
This diploma thesis is focused on the analysis of basic problematics of dielectrics and nanocomposites. It describes the fabrication of experimental samples of nanocomposites from sealing epoxy resin and nanoparticles of titanium dioxide with various weight filling. Further, the thesis deals with measuring and evaluation of dielectric properties of the samples. It examines the influence of weight filling, temperature and frequency of the electric field on volume resistivity, relative permitivity and loss factor.
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Design of high voltage source for electrical ageing of insulating mater
Příborský, Václav ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
Target of this thesis is analyse problems of dielectric materials ageing and environment characteristic applied by ageing process. Types of electric stress are comparing in this work, when and how they are working and how to eleminate them. Next aim is design the high voltage sinus transformer as source for measuring of electric stress and ageing dielectric materials. There is discuss about computer control and collecting of the output datas. In the end is source testing by practical measurement of some dielectric samples.
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