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Evaluation of a switching device behaviour during short-circuit current
Fendrych, Martin ; Dostál, Lukáš (referee) ; Valenta, Jiří (advisor)
At work, I focused on the principle of electric arc extinction in low voltage devices. I particularly focused on the issue of magnetic switches. Next, I processed by the theory site issue of contact system in magnetic switches. In the practical part of my work, I was testing modular low voltage circuit breaker type of 2B and 10B. Testing was carried out in the laboratory of switchgear. I observed the movement of the contact and electric arc, which was burned between them and conductor wall. Observation was recorded by using a high-speed camera and an oscilloscope. Of acquired waveforms, I evaluated the dynamics of contacts, electric arc length and the value of the arc voltage for different moments.
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Simulation of charged particles motion in electrical and magnetic fields
Zavřel, Marek ; Kloc, Petr (referee) ; Aubrecht, Vladimír (advisor)
In the first part of this bachelor thesis has been explained a basic idea of plasma state. In the second part have been described charged particle motions in various configurations of electric and magnetic fields. These motions are: accelerating and deflection of charged particle by electric field, gyration in magnetic field and drift motion in crossed electric and magnetic fields. Principles of magnetic mirror and magnetic trap were described as well. In the third part have been described operating principles and manipulation with simulation program, which is the main outcome of this thesis. Simulation program draws trajectories of mentioned charged particle motions in homogenous electric and magnetic fields.
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Aerodynamic Characteristics Identification of Atmospheric Airplane from Flight Measurement Results
Zikmund, Pavel ; Salga,, Jaroslav (referee) ; Jebáček, Ivo (referee) ; Daněk, Vladimír (advisor)
The thesis deals with aerodynamic characteristics identification from flight measurement. The topic is part of flight mechanic – handling qualities. The first theoretic part consists of three identification methods description: Error equation method, Output error method and Filter error method. Mathematical model of an airplane is defined and restricted to the motion with 3 degree of freedom. There is also introduced simulation of flight measurement for identification software validation. Practical part is focused on experiment preparation, execution and evaluation. The airplane VUT 700 Specto had been chosen to carry out flight tests. The airplane was modified to the new electric powered VUT 700e Specto after first measurement flights with combustion engine. Data record from on-board measurement unit was completed by telemetric data from autopilot and remote control system. Flight tests were carried out in stabilised mode of autopilot in symmetric flight. The results were confronted with analytical analysis results and DATCOM+ software parameter estimation.
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Aerodynamic Characteristics Identification of Atmospheric Airplane from Flight Measurement Results
Zikmund, Pavel ; Salga,, Jaroslav (referee) ; Jebáček, Ivo (referee) ; Daněk, Vladimír (advisor)
The thesis deals with aerodynamic characteristics identification from flight measurement. The topic is part of flight mechanic – handling qualities. The first theoretic part consists of three identification methods description: Error equation method, Output error method and Filter error method. Mathematical model of an airplane is defined and restricted to the motion with 3 degree of freedom. There is also introduced simulation of flight measurement for identification software validation. Practical part is focused on experiment preparation, execution and evaluation. The airplane VUT 700 Specto had been chosen to carry out flight tests. The airplane was modified to the new electric powered VUT 700e Specto after first measurement flights with combustion engine. Data record from on-board measurement unit was completed by telemetric data from autopilot and remote control system. Flight tests were carried out in stabilised mode of autopilot in symmetric flight. The results were confronted with analytical analysis results and DATCOM+ software parameter estimation.
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Numerical Simulations of Dynamic Loads in Wheel-Rail Contact with Shape Irregularities
Jandora, Radek ; Malenovský, Eduard (referee) ; Schmidová, Eva (referee) ; Janíček, Přemysl (advisor)
During life of railway vehicles, shape irregularities develop on wheels and rails because of wear. The shape irregularities then affect forces in wheel-rail contact and cause further damage of contact surfaces, vibrations and noise and increase risk of derailment. A numerical simulation of railway vehicle motion with more details on contact surfaces geometry was created to investigate dynamic contact loads in wheel-rail contact. A variety of methods can be used to evaluate forces in rolling contact, the method chosen for this study was algorithm CONTACT based on boundary element method. Four studies are presented in this papers: contact loads from a wheel with a flat and with a wavy tread pattern, loads on wavy rail and load in a curve. The first three studies investigated effects of existing wear patterns, the last one looked for cause of common wear pattern developing on rails. Results of the studies with worn components used showed that the worst kind of shape irregularities is a flat present on wheel. This type of shape cause loss of contact and following impacts. The study of ride in curve showed that cause of high wear in curves, especially those with small radii, is caused by vibration of wheelset. This vibration is then caused by different length of inner and outer rail and wheels travelling along a different path.
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Numerical Simulations of Dynamic Loads in Wheel-Rail Contact with Shape Irregularities
Jandora, Radek ; Janíček, Přemysl (advisor)
During life of railway vehicles, shape irregularities develop on wheels and rails because of wear. The shape irregularities then affect forces in wheel-rail contact and cause further damage of contact surfaces, vibrations and noise and increase risk of derailment. A numerical simulation of railway vehicle motion with more details on contact surfaces geometry was created to investigate dynamic contact loads in wheel-rail contact. A variety of methods can be used to evaluate forces in rolling contact, the method chosen for this study was algorithm CONTACT based on boundary element method. Four studies are presented in this papers: contact loads from a wheel with a flat and with a wavy tread pattern, loads on wavy rail and load in a curve. The first three studies investigated effects of existing wear patterns, the last one looked for cause of common wear pattern developing on rails. Results of the studies with worn components used showed that the worst kind of shape irregularities is a flat present on wheel. This type of shape cause loss of contact and following impacts. The study of ride in curve showed that cause of high wear in curves, especially those with small radii, is caused by vibration of wheelset. This vibration is then caused by different length of inner and outer rail and wheels travelling along a different path.
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Study of arc root movement in a model of the LV quenching system
Fendrych, Martin ; Aubrecht, Vladimír (referee) ; Valenta, Jiří (advisor)
Thesis focuses on the basic characteristics of plasma, problems about origin of electrode spots and electrodynamics force acts on the electric arc. In the practical part was realized and produced model of a LV quenching system. Using optical diagnostics was received necessary data to analyze the movement of the electrode spots. The movements of the electrode spots were analyzed in terms of value RMS current passing through the electric arc, value of absolute pressure model in the LV quenching system and distance from each electrode.
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