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Switching of modern LED light sources
Dobrovolný, Jakub ; Fencl, Jiří (referee) ; Dostál, Lukáš (advisor)
The protection of the electrical device is provided to prevent the electric shocks, protect the equipment and prevent a damage caused by electrical faults. The current protection for a small fault currents need not always have an effect. At the serious faults the current protections never work. The new type of device to protect against damage caused by electrical failure is an arc protection. The arc protection switches off safely all types of fault arc in different sizes. This work verifies its correct functionality in the case of electric circuit with deceptive signals from LED light sources. The output of the work is the measurement of the switching current of the LED light sources. The work is remarkable thanks the number of measurement for individual angles of switching on which have statistical meaning.
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Temperature analysis of molded case circuit breaker's current path
Mejzlík, Tomáš ; Makki, Zbyněk (referee) ; Dostál, Lukáš (advisor)
The work deals with the preparation of dimensional drawings, circuit-breakers and switching elements for inclusion in the database devices. Part of the original drawing documentation is from the U.S. catalogue EATON. Preparation of drawings from the catalogue meant to convert the projection between U.S. and European, including compliance with ISO and ČSN, redraw geometry to the CAD system using Autodesk AutoCAD 2010 and complete dimension. Another part of the project was to model the two completely dimensioned breakers in 3D space, along with their implementation in the model EATON cabinet, including the construction of their connections to buses and cable entry.
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Calculation of the distribution of temperature field of induction machine
Suk, Jiří ; Dostál, Lukáš (referee) ; Janda, Marcel (advisor)
The issue of this bachelor’s thesis is calculation of the distribution of temperature field of induction machine. There is used three different methods of calculating which are compared in the conclusion. First method is lab measuring of surface temperature on different spots on the machine while unloaded without active cooling. Temperature is measured on four spots using different devices. Another way how to calculate temperature field is computer simulation in ANSYS Workbench using finite elements method. In this method is necessary to create real-based model of motor in CAD system. In this case Autodesk Inventor 2015 was used. Last method was simplified analytics calculation using heat circuit of the stator part. Last but not least is comparison of all used methods, results and accuracy of calculation.
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Diagnostics of medium voltage and high voltage circuit breakers
Kapalla, Alexej ; Šimek, David (referee) ; Dostál, Lukáš (advisor)
This semestral work is about high voltage switchgears and their diagnosis. In this work there is part about history of HV switchgears and their dividing. Next part of this work describes diagnostic of HV switchgears VD4 24 ABB and AEG S1-245. In case of HV breaker VD4 there was provided diagnostics of new VD4 and used VD4. The measured values are then compared in the work and the influence of usage of breaker is presented according to his parameters. This work describes measurment of resistance of main contacts, insulation states.
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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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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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Electric fault arc detection in LV network
Dubský, Martin ; Fencl, Jiří (referee) ; Dostál, Lukáš (advisor)
This thesis deals with arc detection using AFDD. Here is explained the general theory of electric arc. It also describes the principle of operation of the AFDD device, a specific type of instrument from OEZ s.r.o. and describe the test procedure for this instrument according to the technical standard. In the practical part, selected tests are performed and verified the function of the AFDD device in the event of a disturbance electric arc in the circuit.
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Seismic test of the switching devices on the low voltage
Dubský, Martin ; Mikyska, Kamil (referee) ; Dostál, Lukáš (advisor)
This work analyzes the seismic tests to valid technical starnards. Here is explained the term technical standard and written summary requirements for seismic resistance circuit breakers low voltage. The work includes devices suitable for the purpose and extreme laboratories dealing with seismic tests. The final section provides a draft test station with estimated economic return. Seismic tests are a very important part in the design of not only switching technology. It allows you to simulate the selected mechanical effects which may on the unit during operation or transportation to work and increase its reliability.
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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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Residual current device behavior under switching of non-sinusoidal residual currents
Horký, Jakub ; Dostál, Lukáš (referee) ; Valenta, Jiří (advisor)
This bachelor deals with behaviour of a residual-current device during disconnection non-sinusoidal residual current. In the first, theoretical part, basic characteristics and properties of electrical devices are described. Attention is devoted to residual-current device, its structural part, parameters and types. Afterwards, there are described normative requirements of the residual-current device type A in the course of tests. The second part is a practical part. The residual-current device is subjected to residual currents with direct current components (according to the standard), thereby it is checked if it works correctly, it means, if the device is capable of being cut off, At the end of the bachelor, where is a sample laboratory task that demonstrates a check the behavior of the residual-current device at switching off the non-sinusoidal current.
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