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The temperature profile of the power switching device of low voltage for different operating conditions
Mejzlík, Tomáš ; Valenta, Jiří (referee) ; Dostál, Lukáš (advisor)
The heat generated in a circuit breaker can be transmitted in two ways: Either through metal parts of current path to conductors outside of device or through plastic parts or air of chassis. The accuracy of the simulation depends on the accuracy of the 3D model and all his parts and it also depends on precise definition of materials with precise definition of electrical and thermal parameters. Electrical circuit breaker has various source of the heat which results in raising temperature of the device above the level of environment. Heat sources are: 1) Joule’s loss of the circuit breaker current path. 2) Heat loss in a bimetal, which is used for thermal release. 3) Resistivity of contacts. This thesis deals with static state of thermal analysis so the sources do not include transient heat source for switching OFF and switching ON. Electrical circuit breakers are made in smaller and smaller forms however their electrical parameters are not decreasing with size. There is logical conclusion that there is more heat on the same unit size which makes thermal analysis of circuit breaker one of the most important part of development.
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Current transformers 12kV, 4000 / / 5/5A
Šumberák, David ; Vaněk, Jaromír (referee) ; Dostál, Lukáš (advisor)
This master´s thesis describes the development proposal and production of instrument current transformer in one turn primary winding with 4000//5/5 A transfer. The thesis involves a theoretical analysis, a numerical calculation, a developmental 3D model, corresponding simulations and a standard testing of the transformers. There is a complete written description of measuring current transformer cycle from the development to the production. The transformer development and production works were collaborated with the company KPB Intra s.r.o. The company engages in development, production and sale of these kinds of instrument transformers in the Czech Republic and foreign markets.
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Brightness control of light sources
Dostál, Lukáš ; Vorel, Pavel (referee) ; Huták, Petr (advisor)
Thesis is focus on brightness control of lighting sources. The first objective of the thesis is to determine basic concepts and explain interrealationships among particular magnitudes of lifting technology. Further is necessary describe functionality, particular light sources and thein possibility of use in practise. There is also outline issue of darkfall of particular types of sources and their evolution. The other part of thesis compare energy output of lighting sources and describe their possible future development. Further this thesis deals with options of regulating of brightness for LED moduls. There is also proposal of acceptable amperage regulator LED moduls including its software - microcontrol ATMEL AVG. Microcontrol ATMEL AVG Tiny 13 is programme in C language within computer environment AVR Studio 4 and will be record through the use of AVR Dragon.
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Diagnosis of mechanical vibrations in asynchronous motor origin
Dostál, Martin ; Dostál, Lukáš (referee) ; Janda, Marcel (advisor)
Every machine needs to be maintained and controlled, if may work reliably during they service life. Big part of service life of expensive machines are those machines in operation. Vibration diagnostics is type of analysis, that doesn’t need removal of rotation machinery. The vibration, that are created by running machinery, are used as source of information about mode of operation. This master’s thesis contains theoretical analysis of vibration diagnostics and vibration measurements of a particular machine. This thesis contains 3D models of bearings and rotor asynchronous machine, which are created by software Autodesk Inventor 2014. Bearings vibration analysis of this models is performed by software Ansys Workbench.
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Diagnosis of electromagnetic origin vibrations in asynchronous motor
Koníček, Pavel ; Dostál, Lukáš (referee) ; Janda, Marcel (advisor)
The aim of this master´s thesis is to introduce methods of diagnostics of vibrations in electrical machines. Describe the various vibration sources located inside and outside of the electric machine. Description of the sources of vibration is then preferably dedicated to vibration of electromagnetic origin. There is a description of the construction of an asynchronous motor and the magnetic circuit, the theory of vibrations and their origin. Described are also vibration sensor enables measurement and mathematical tools for their evaluation. In this work also practical vibration measurements on an asynchronous motor, data processing, their subsequent analysis and computer simulation of electromagnetic vibration origin. The conclusion of this work is devoted to the evaluation of the data obtained.
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Switching mechanism in the molded case circuit breaker
Mejzlík, Tomáš ; Valenta, Jiří (referee) ; Dostál, Lukáš (advisor)
This paper deals with mechanical switch in circuit breaker designed for low voltage. The goal of this thesis was to analyze switching mechanism both theoretically and practically. Theoretical analysis consist of study different types of switching mechanism and analytical calculations of acceleration speed and trajectory. Practical analysis has been made taking a video with high speed camera of real switching mechanism of a circuit breaker and software analysis of the data. The next part of a thesis is about 3D modeling, animating and simulating of a switchgear switching mechanism.
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Simulation of circuit breaker maglatch dynamic behaviour
Konšel, Ladislav ; Dostál, Lukáš (referee) ; Valenta, Jiří (advisor)
This work includes the theory of circuit breaker construction and is focused mainly on overload function. It mainly deals with electronic circuit breakers, i.e. equipped with an electronic trip unit. The work is focused on the part of trip unit - maglatch of trip unit. For the purposes of simulation, the geometric model is created. Maxwell program is used for the simulation. The work describes the options for conditions input which are necessary for simulation. Using the distribution of magnetic field intensity and magnetic flux density in the section of trip unit maglatch is determined by the simulation. Furthermore, the force effects acting on the armature of the maglatch are calculated. Force values and the directions acting on the armature are determined by changing the simulation parameters - shift of the armature and coil current. Simulations are performed both for steady-state and for dynamic simulation – movement of armature is taken into account. The supply source for the maglatch is created by an external circuit.
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Optimization of the cooling of induction machines
Halfar, Ivo ; Dostál, Lukáš (referee) ; Janda, Marcel (advisor)
This master‘s thesis deals with problems of optimization of cooling in electrical machines. This work includes introduction to the theory of mathematical optimization and brief introduction to optimization problems. This thesis deals with using of program Ansys Workbench for the thermal analysis in electrical machines and optimization of their cooling. Thesis contains thermal analyse of specific asynchronous motor with the squirrel cage and optimization of its cooling.
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Simulation of circuit-breaker trip unit
Dostál, Lukáš ; Augusta, Zbyněk (referee) ; Valenta, Jiří (advisor)
Securing of electrical devices is important not only to protect against destruction under the effects of electric current, but also for protection of people or animals against electric shock. With increasing of living standards goes hand in hand increasing of the electricity consumption. Therefore In the grid of low voltage, there are increasing short-circuit currents. With improving technology is posed considerable demand on the performance, security and switching capacity of circuit breakers. This thesis is oriented on development of thermal and electromagnetic switch of circuit breaker on which is put a big demand in development of new types of circuit breakers. The thesis is interesting because of comprehensive use of circuits’ breakers since it can be used in AC and DC networks with frequency of 50 Hz and 400 Hz.
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Sanitary facilities for football players with a dwelling
Dostál, Lukáš ; Jurutková, Zuzana (referee) ; Remeš, Josef (advisor)
The project consists of social facilities for a football field. It is a two-story object, which has a supporting system consisting of ceramic blocks and concrete-ceramic ceiling. The building roofing is created by a a flat walking roof and a mono-pitched roof. The project is divided into three operating parts. The main part is formed by dressing rooms with social facility for football players with rehabilitation - sauna, the second part includes a field custodian apartment and the third part is represented by social facilities for visitors.
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