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Analysis of steel grade influence on small induction machine efficiency
Plíšek, Oldřich ; Klíma, Jiří (referee) ; Mach, Martin (advisor)
The theoretical part of the bechelors thesis examining the impact of the material of the magnetic circuit on the efficiency of induction motors is devoted to analysis of the induction motor and its losses. It also describes the measuring, including calculations of individual losses. Another theoretical part examines the impact of specific losses on the magnetization characteristics of assessed laminations. The practical part includes laboratory measurements of single phase and three phase motors ATAS Electromotory Náchod brand with multiple types of laminations. Measured values are used to calculate individual losses, which are later mutually compared. Models of measured motors with multiple types of laminations are simulated with the aid of ANSYS Maxwell RMxprt program. Analysis of engines with specific types of laminations are performed with the aid of analytical calculations. Results of calculations are compared with simulated and measured values.
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Test parameters and conditions of amorphous photovoltaic modules
Kostelník, Adam ; Křivík, Petr (referee) ; Vaněk, Jiří (advisor)
This master’s thesis deals with the problem of thin film solar cells, their parameters and measuring. The introductory chapter describes the properties of individual thin-film technology, summarizes their advantages against the crystalline silicon cell. Another chapter is exclusively focused on thin-film cells based on amorphous silicon. There is described the manufacturing processes of amorphous cells and modifications performed during the manufacturing. One part of master’s thesis is dedicated to the description of basic electrical quantities and PV cell degradation mechanisms that negatively affect these electrical properties. It is explained in detail the most important degradation phenomenon called Steabler - Wronski effect. The master’s thesis describes standards regarding testing amorphous cells as well as method, how to achieve their performance stability. The practical part is focused on the testing of several single-layer amorphous cells that were exposed to degradation and regeneration effects. One part of the thesis is studying of a new method of testing of amorphous cell, where is necessary to determine whether it is the degradation or regeneration process. Measured values obtained from several types of measurements were compared, evaluated and displayed in the graphs. The recommendation for future testing of amorphous article is stated in the final chapter.
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Methods of secondary influencing steel and steel ingot structures
Šprta, Pavel ; Pernica, Vítězslav (referee) ; Blažík, Petr (advisor)
This bachelor’s thesis deals with heat treatment of steels. Iron-carbon diagram and basics of heat treatment are described in the beginning of the literature search. Further the thesis focuses on austenitization and changes during decomposition of austenite. Introduction to transformation diagrams and their use is also included in this thesis. At the end the thesis focuses on description of individual heat treating methods. The experimental section contains metallographic analysis of 4 samples made of low carbon steel.
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Heat treatment of aluminum castings
Mátl, Vojtěch ; Pernica, Vítězslav (referee) ; Kaňa, Václav (advisor)
This bachelor thesis deals with the topic of heat treatment of aluminium castings. The first part of this thesis comprises of casting alloys and casting technology summary, followed by description of aluminium heat treatment. The second part descibes an experimet, that examins the effect of conditions during aging upon final aluminium alloy properties.
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Present state of investment casting technology
Soukupová, Lucie ; Šmíd, Dušan (referee) ; Horáček, Milan (advisor)
The Bachelor’s thesis deals with the latest trends in investment casting technology, from wax pattern manufacture, ceramic shell manufacture, de-waxing, shell heat treatment up to metal pouring and finishing operation. In the first part, the outline of the world production and the usage of investment castings nowadays are introduced. The other parts of the project include the basic technique of using new technologies. The aim of this work is developing a literature search focused on the most modern equipment and raw materials that are used in investment casting technology and testing of wax mixtures and ceramic slurries.
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Recovery and recrystallization of austenitic steel 08Cr18Ni10T
Čech, Jan ; Gregor, Martin (referee) ; Foret, Rudolf (advisor)
This thesis deals with influences of graded deformations, temperatures and holding times on the grains and subgrains size in steel 08Cr18Ni10T. In literary part of the thesis there are described static and dynamic annealing treatments, then also austenitic stainless steels and some selected types of their processing. In experimental part there is studied grain size on differently deformed samples annealed in temperature range 1050–1200 °C for 10, 50 and 100 minutes. Analysis of present structures units was perform by EBSD. Except of that, there were realized chemical analysis of selected inclusions and also hardness test were realised. Achieved measurement shown, that grain size of chosen steel is depended on all 3 variable values.
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Design of synchronous reluctance motor with permanent magnets
Knebl, Ladislav ; Huzlík, Rostislav (referee) ; Ondrůšek, Čestmír (advisor)
V dnešní době je kladen vysoký nárok na účinnost elektrických zařízení a to jak ze strany provozovatele, tak i legislativy. Nejlepší účinnosti dosahují synchronní motory s permanentními magnety umístěnými na povrchu rotoru (SMPM), se kterými lze i u malých motorů dosáhnout účinnosti nad 90%. Nicméně tyto motory jsou z důvodů použití magnetů ze vzácných zemin, např. NdFeB, drahé a jsou schopny provozu pouze s frekvenčním měničem. Z cenových důvodů jsou hledány levnější alternativy k SMPM motorům. Jedním z typů motorů, kterým lze SMPM nahradit je synchronní reluktanční motor s permanentními magnety (PMASR). Tento motor je cenově výhodnější, protože používá menší množství magnetů, při zachování podobných, mnohdy i lepších vlastností, nicméně neodpadá potřeba použití frekvenčního měniče. Navíc je zde možnost použití levnějších feritových magnetů a tím ještě výrazněji snížit cenu motoru. V této práci bude PMASR topologie popsána důkladněji včetně elektromagnetického návrhu metodou konečných prvků. Bude provedena i mechanická analýza zvoleného optimálního modelu. Výsledky dosažené metodou konečných prvků budou následně porovnány s analytickým modelem. Z navrženého modelu bude vyroben prototyp a naměřené výsledky budou porovnány s výpočty.
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Heat treatment of iron alloys with carbon
Kubíček, Antonín ; Štěpánek, Roman (referee) ; Čupera, Jan (advisor)
This thesis deals with the processes of heat treatment, their impacts on microstructure of iron alloys with carbon and their influence on hardness of these alloys. In the research part of this thesis are discussed the alloys, which are found within the Fe-Fe3C metastable system, principles and technologies of heat treatment processing with focus on the annealing, methods of microstructure examination and hardness measurement. In the experimental part is documented and evaluated the influence of various types of annealing on hypoeutectoid and hypereutectoid steels and the influence of graphitization on the hypoeutectic cast iron. The evaluation involves comparison of microstructures obtained by light and scanning electron microscopy and comparing the hardness in the green state and after annealing.
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Microstructure and properties of YSZ thermal barier coatings deposited onto CoNiCrAlY bond coats remelted by electron beam
Slavíková, Barbora ; Jan, Vít (referee) ; Dlouhý, Ivo (advisor)
The master thesis is dealing with characterization of the structure and properties of the YSZ thermal barrier coating deposited by water hybrid plasma spray technology on the CoNiCrAlY bond coats modified by using electron beam and vacuum annealing. Deposition of the bond coats was performed via high velocity oxy-fuel technology and cold spray. In case of experimental evaluation, the microstructure and chemical composition of the ceramic top coat deposited with powder and suspension feedstock was analyzed. The same analysis procedure was used also for bond coats after electron beam remelting by using two sets of parameters. Furthermore, the changes in microstructure and chemical composition of the remelted and annealed bond coats was evaluated. Eventually, the micromechanical properties of the top coats and the bond coats were measured. The ceramic top coats deposited with powder feedstock exhibited the structure composed by splats, while the top coats deposited in form of suspension showed fine structure with columnar grains. The dendritic structure was observed on remelted bond coats. The annealing process had an influence on the structure in form of coarsened phases and the chemical composition was changed due to diffusion of the elements.
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