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Inorganic fillers effect on electrical properties of the epoxy resins
Doležel, Tomáš ; Jirák, Josef (referee) ; Frk, Martin (advisor)
This thesis deals with problems of electrical insulation materials based on epoxy composites used in the electronics industry. This thesis is divided into theoretical part focused on composite materials, their technological processing and diagnostics. It also describes dielectric materials, their properties and events taking place in their structure. The experimental section describes the measurement of electrical properties of samples of electrical insulating materials with different types of fillers.
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Measurement of HV equipments by electronic bridge.
Kumičák, Ivan ; Pelikán, Luděk (referee) ; Krbal, Michal (advisor)
The main idea of this thesis is measurements of dielectric materials by using a device Tettex. The thesis is about basic physic properties of dielectric materials. The determination of a dielectric material is considered. The behavior of these materials in electrical fields and reasons, those can have an influence on it, are considered as well. In the text are described measuring methods of chosen parameters of dielectric materials by device Tettex and its functional principles. There are an evaluation of measurements, which were done, and a discussion about achieved results.
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Dielectric absorption characteristics of stressed slot insulations
Přikryl, Tomáš ; Frk, Martin (referee) ; Rozsívalová, Zdenka (advisor)
Master's thesis is monitoring changes in basic dielectric properties. Monitoring changes in absorbency of characteristics and temporal dependences in rezistance with change of relative humidity. On the colection samples were measured temporal dependences charged and uncharged currents in ambient temperature and 0%, 55%, 75%, 95% relative humidity. The next part of my work is monitoring temporal dependences interior rezistance in the time of ageing in different humidities. Experiments were made on material ISONOM NKN and NMN.
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Degradation of nanocomposites
Polách, Ondřej ; Rozsívalová, Zdenka (referee) ; Polsterová, Helena (advisor)
The present work deals with the electrical properties of nanocomposite materials. Samples for the practical part consisting of epoxy resin as matrix and SiO2 as nanofillers and were made in four different percentage performance. There is investigated the influence of thermal degradation of nanocomposite materials change resistivity, loss factor and relative permitivity.
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Modification of electroinsulating varnish with ground mica
Drápal, Aleš ; Frk, Martin (referee) ; Rozsívalová, Zdenka (advisor)
This master's thesis focuses on composite systems based on varnish combined with different filler ratios of micronized mica. The aim is to analyse impact of the filler on dielectric properties of the varnish, i.e. relative permittivity and loss factor as functions of frequency as well as charging and discharging currents as functions of time. Dielectric mixture formulas are applied on relative permittivity values. Calculated and measured values are compared.
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Lead Free Solder Joint - Models for Reliability Prediction
Nestrojil, Michal ; Šandera, Josef (referee) ; Starý, Jiří (advisor)
This bachelor's thesis deals with reliability prediction of lead-free solder joint. Background research of fatigue models for lead free solder joint.is described in theoretic part Basic terminology and lead free soldering technology operations are mentioned in the theoretical part too. The practical part is dealing with observation of resistivity and solder joint strength during thermal cycling. Evaluation of results and experiments and posibility for future application of these results for fatigue model realisation is discussed in the end of this bachelor's thesis
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Dielectric Absorption of Electroinsulating Materials
Pavlinský, Branislav ; Krbal, Michal (referee) ; Pelikán, Luděk (advisor)
This bachelor thesis deals with the basic physical principles of dielectrics as well as the description of the phenomenon of dielectric absorption. The work presents diagnostic methods that use this phenomenon, based on the events taking place in the dielectric after the connection of DC voltage. Furthermore, the work deals with diagnostic methods for determining the state of insulation of various high-voltage electrical equipment. The work also deals with the properties and parameters of electrical insulating materials - specifically polymers. We obtain these parameters using the mentioned diagnostic methods. By knowing these parameters, we achieve enough information about the insulation to determine its condition and prevent possible damage.
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Study of electric properties of nanocomposites
Libra, Miroslav ; Rozsívalová, Zdenka (referee) ; Polsterová, Helena (advisor)
The present master´s thesis deals with the electrical properties of nanocomposite materials. Samples for the experiment are made epoxi resin and oxides TiO2 and Al2O3 as nanofillers in different percent performace. The samples nanocomposites are measured temperature dependence of the resistivity inside, dissipation factor and relative permittivity. It discusses the effect of the filler on the resulting electrical properties of the polymer.
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