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Temporally and spatially resolved diagnostics of an electric arc
Holcner, Oldřich ; Šimek, David (referee) ; Kloc, Petr (advisor)
This batchelor thesis "Temporally and spatially resolved diagnostics of an electric arc" deals with the investigation of plasma temperature in an arc formed by evaporation of copper wire. It is an optical method based on determination of temperature from intensity of spectral lines. In this batchelor thesis we explain how spectral lines are formed and how to determine the temperature. In the practical part we process discharge and show the time evolution of temperature at the measured points.
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Effects of electrical discharges on the Mars´ atmosphere
Fojtíková, Nikola ; Horák, Jakub (referee) ; Kozáková, Zdenka (advisor)
The aim of this thesis was to study the effects of electric discharge on the atmosphere simu-lating conditions on Mars. This bachelor thesis is focused on simulation of Mars atmosphere at atmospheric pressure and normal laboratory temperature. Mars's atmosphere was more like Earth in the past. Mars is mostly composed of carbon dioxide, which accounts for more than 90% of Mars' atmosphere. To study the Mars atmosphere simulation, glow discharge generated in the reactor at atmospheric pressure was used at a CO2 flow (100 sccm) and dis-charge current of 20, 30 and 40 mA. A part of the measurements was focused on the influ-ence of hydrogen addition at different flow rates. The measurement time course with differ-ent measurement changes was also recorded. Reaction products were analysed using a pro-ton ion mass spectrometer and a flight time analyser. A high amount of aliphatic hydrocar-bons and their derivates, especially alcohols, was detected as well as several cyclic struc-tures. The main products identified in all experiments with a substantial concentration were molecules of ethen, ethane, ethanol, acetone, pentane, benzene and others.
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Possibilities of elimination of electrostatic charge generation in the belt conveyor drive
Pavluš, Ondřej ; Mach, Martin (referee) ; Veselka, František (advisor)
The purpose of revision of electrical devices is to assess the device in regard to its safety. The main goal of this bachelor thesis is a revision of an electrical conveyor belt engine. We focus on safety from injury caused by electric current due to malfunction and methods for detection and prevention of electrostatic charge buildup. We conducted an inspection and prepared the required norms and measurements. After a careful analysis of results we determined, whether or not the device meets the safety requirements specified by the relevant industry norms. Based on the insights from the inspection, we took necessary precautions with regard to static electricity buildup.
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Spectroscopic analysis of an electric arc
Hartman, Tadeáš ; Kloc, Petr (referee) ; Šimek, David (advisor)
The bachelor thesis deals with spectroscopic diagnostics of electric arcs. The first part explains the creation and properties of electric discharges, especially electric arcs. Methods for composition and temperature analysis of electric arcs are also given there. The next part deals with practical use of these methods for identification of elements contained in electrodes between which an arc discharge was happening, measurement of the arc temperature and also measurement of the temperature of the electrodes. In the last part, these methods are also used for the analysis of time progression of composition and temperature of an electric arc created on a contactor's contacts with the resistive load.
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Electrical characteristics of gliding discharge for VOC decomposition
Jeřábek, Martin ; Sysel, Petr (referee) ; Bartlová, Milada (advisor)
The subject of this bachelor's thesis was to get familiar with the characteristics of plasma, its divisinon and diagnostics. In physics and chemismy plasma is considered to be, an ionized gas composed of ions, electrons (and possibly neutral atoms and molecules), which is produced by detachement of electrons from the atomic shell, or by dissociation and ionization of molecules. The plasma is often referred as the fourth state of matter. Attention was given to the description of various types of electric discharge, its characteristics and occurrence. One of the most idey known electrical discharges occurring in nature is lightning, a spark discharge, which occurs in the storm. Lightning is an electric discharge between centres of positive and negative charge of one or more clouds, between cloud and earth, or rarely between the cloud and the stratosphere. The greatest attention is paid mainly to gliding electric arc discharge, called Glide-Arc; it is a representative of on-thermal plasma formed by weakly ionized gas. It has many industrial applications, especially for its high energy efficiency, specific productivity and high selectivity of chemical reactions. Under low and atmospheric pressure, Glide-Arc represents a simple and non-expensive way of non-thermal plasma generation. The discharge is excited between two electrodes of different materials in the pressure range from very low pressures up to the pressures of the order of units of MPa. The gliding arc system consist of horn-gaps electrodes diverging in the direction of the working gas flow. After the application of DC or AC voltage, a breakdown occurs at the smallest distance between the electrodes, and a spark plasma channel drifts (“glides“) in the direction of the flowing gas. The final experimental part deals with the measurement of VA characteristics and oscillation characteristics of the current, and with the determinativ of gliding arc ignitron for selected of nitrogen and methane gases at various flow rates. The values of ignition voltage for variol mixtures of gases have been compared. Furthermore, the properties various combinations of gases at different gas flow rates have been evaluated. Measurements were carried out in the plasma laboratory of the Faculty of Chemistry BUT in the plasma reactor at the atmospheric pressure.
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Influence of Change in Frequency of the Supply Current to the Operational Parameters of the Discharge Light Sources
Kuptsov, Alexander ; Škoda, Jan (referee) ; Krbal, Michal (advisor)
The master’s thesis is devoted to exploiting of gas-discharge lamps and their dependence on frequency of the supply current. The first part describes the theory of discharge, its types and properties, terms of its origin, and ways of its exploitation. The second part concerns electrical ballast systems of gas discharge light sources, inductive (reactive) and electronic ballasts, principles of their functioning, advantages and disadvantages, and the comparison of their properties. The following chapters deal with low-pressure and high-pressure gas-discharged lamps, compare their properties and describe exploitation of fluorescent lamps. Before conducting laboratory experiments the influence of frequency of the supply current on different properties of gas-discharge lamps was described. Besides, simulation of basic electric parameters of high-pressure gas-discharged lamps was implemented in the program SIMULINK/MATLAB. As a result, the received graphs show the dependence of current, voltage and electric power on time. Another simulation included building of dynamic current-voltage characteristics at various frequencies of the supply current. Preparations for the laboratory experiment and the experiment itself were implemented. Compact and tube low-pressure fluorescent lamps were measured. The received graphs show the influence of change in frequency of the current on the operational parameters of the discharge light sources.
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Influence of Change in Frequency of the Supply Current to the Operational Parameters of the Discharge Light Sources
Kuptsov, Alexander ; Škoda, Jan (referee) ; Krbal, Michal (advisor)
The master’s thesis is devoted to exploiting of gas-discharge lamps and their dependence on frequency of the supply current. The first part describes the theory of discharge, its types and properties, terms of its origin, and ways of its exploitation. The second part concerns electrical ballast systems of gas discharge light sources, inductive (reactive) and electronic ballasts, principles of their functioning, advantages and disadvantages, and the comparison of their properties. The following chapters deal with low-pressure and high-pressure gas-discharged lamps, compare their properties and describe exploitation of fluorescent lamps. Before conducting the experiment we have described the influence of frequency of the supply current on fluorescent tube lamps. Preparations for laboratory measuring have been also implemented. During the experiment the two types of lamps have been analyzed, the results of the research are summed up in the conclusion.
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Utilization of electrodischarge machining technology
Dlabaja, Zdeněk ; Mouralová, Kateřina (referee) ; Osička, Karel (advisor)
Electrical discharge machining (EDM) is quite simple but very effective method for machining of materials. This method has an irreplaceable place in modern engineering. The technology of the EDM is theoretically described in this work. The aim of this work was to judge the advantages and disadvantages of this technology, and its application in a tool company Brenas, Ltd. A component typical for production using EDM was chosen for this judgement. The shape complicatedness and necessary dimensional and surface quality can be clearly seen in this component.
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