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Influence of welding direction on depth of penetration for MAG method
Šmak, Radim ; Mrňa, Libor (referee) ; Kubíček, Jaroslav (advisor)
This bachelor thesis deals about Influence of welding direction on depth of penetration in S 235 JR steel for MAG welding. First theoretical part of the thesis was devoted to a description and technology of the chosen method. In the second practical patr of the thesis was designed optimal welding parameters and conditions of welding. Based on them was performed an experiment. From the experiment was detected the depth penetration, heat affected zone and structure of the metal.
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Idea design of experimental model for LV electric arc properties investigation
Fazekas, Tibor ; Valenta, Jiří (referee) ; Vávra, Zdeněk (advisor)
The aim of the work was a planing of an experimental model for the observation of the low voltage electric arc. The opening part observes the basics of the electric network switching and the electric arc in theory. The next point is definition about the behaviour of the electric arc in the low voltage switching devices, focusing on the movement of the arc along electrodes and in the extinguish chamber. The design of the experimental model, created in Autodesk Inventor 2008, is described in the last part of the work.
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Welding of steel C45
Hála, Kamil ; Sigmund, Marian (referee) ; Kubíček, Jaroslav (advisor)
The aim of this bachelor‘s thesis is to propose a suitable welding parameters for a small part of steel C45. This steel contains a high percentage of carbon and therefore is difficult to weld. Gas shielded arc welding techniques were considered to be used, and from such techniques, the TIG method seems to be the most advantageous one. For this technique were suggested three groups of parameters and the most suitable one was chosen to be used for the production. The option chosen is of a welding power I=40 A and with preheating 200 °C. The component is made in the single-part production in SAAB Czech s.r.o.
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Electric arc in the switchgear
Kutal, Ondřej ; Dohnal, Petr (referee) ; Bušov, Bohuslav (advisor)
This thesis focuses on description of creation, properties and behavior of an electric arc in the switchgear. In addition, it focuses on description how an electric arc can be created and how it effects contacts in electrical switchgear. Electric arcs is divided into arc with DC or AC. Quenching of the electric arc supplied by DC is more difficult than in case of AC since the DC does not pass through zero value. For the design of quenching chamber it is important to know the characteristics of the electric arc under both conditions. The behavior of static V-A characteristic of the electric arc supplied by DC was determined with experimental measurements using the equation by Ayrton. Subsequently, measurement of the dynamic characteristics of the electric arc with AC were determined. And the limits values for the emergence of electric arc were measured of. Last, the results wereevaluated and expansion of measurement task was proposed. The numerous influences on the arc were described. In conclusion the thesis extends diagnostic of the arc under the laboratory conditions.
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Switching arc plasma diagnostics by usage of two high-speed cameras
Buchta, Martin ; Dostál, Lukáš (referee) ; Valenta, Jiří (advisor)
This bachelor thesis deals with an electrical arc formation and its properties. The thesis also describes some of the electrical devices and principles, which are used for arc extinction. It is mainly focused on design, construction and testing of model of the LV quenching system, which allows high speed cameras to record arc movement. Recorded images are then used to create three-dimensional reconstruction of the electric arc with help of created program 3DMaker. The final reconstruction is the output of this work.
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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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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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Plasma speaker - audio modulated electric arc
Klein, Ondřej ; Červinka, Dalibor (referee) ; Martiš, Jan (advisor)
The bachelor thesis deals with design and realization of electric arc modulated by audio signal. It is also known as plasma speaker. Absence of any mechanical components gives membranless speaker no frequency limitation. The design consist of single circuits as power sources for power and control section, control electronics, which modulates the signal, and power section, which reproduce signal in form of sound.
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The effectiveness of welding on furnace structures.
Rousová, Michaela ; Mrňa, Libor (referee) ; Kubíček, Jaroslav (advisor)
This diploma thesis is resolving all the possibilities of enhancing the efficiency of furnace structures welding. Small batch production does not offer many possibilities for implementing mechanization or automation. On the other hand, when using a big batch production, efficiency can be enhanced by means of a robotic workstation. When the production batch is big enough, we will see a costs save after a short time, mainly in labor costs. This means the return of investments will be in short time period. In the LAC company there are three types of products made. At laboratory furnaces the efficiency can be enhance by using fixtures. At other standard and atypical furnaces is very difficult to design fixtures or positioners because of their different sizes. Big complication can be also a company location on second floor. The most suitable product regarding to welding efficiency enhancement is big batch production of heaters. For this type the welding time can be shortened by means of a robotic workstation.
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Fibre optic tapering and shaping methods for special applications
Hruška, Andrej ; Jelínek, Michal (referee) ; Mikel, Břetislav (advisor)
The thesis deals with the tapering of optical fibres and the shaping of their ends. The thesis describes the fibre tapering and shaping methods and compares them in terms of advantages and disadvantages. It mainly focuses on methods using electric arc, flame and chemical etching. The practical part of the work describes the methodology of fibre tapering for 125 m, 400 m and 1000 m fibre diameters and the methodology of fibre end shaping for 400 m and 1000 m fibre diameters.
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