National Repository of Grey Literature 36 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Temporal Development Of Relative Ablation Of Plastics In Miniature Circuit Breaker During Switching Process
Simek, David
The paper is focused on an ablation of plastic materials in contact with an electric arc inside the electrical apparatus during the switching process. It is possible to obtain temporal development using method based on optical emission spectroscopy. The emission spectra were taken during the switching process. The hydrogen alpha spectral line of Balmer series was used as an indicator for evaluating of plastics ablation. Complications connected with the measurements are discussed. The main part of the paper deals with a temporal development of relative concentration of a hydrogen in plasma inside the miniature circuit breaker. Atomic spectral lines database of National Institute of Standards and Technology was used as a spectral data source for evaluation.
DC arc extinguishing in low voltage switching devices for critical currents
Fencl, Martin ; Šimek, David (referee) ; Píška, Jakub (advisor)
This bachelor’s thesis deals with DC arc extinguishing for critical currents. The first, theoretical part describes and defines an arc, a DC arc and methods of its extinguishing. The second, theoretical part concerns spectral analysis – specifically, the emission method. Methods of research of extinguishing critical currents are also presented. The practical part consists of two measurements. The first measurement consists of spectrum measuring in time, in conjunction with voltage and current measurements. In the second measurement, the goal was to measure the dependence of arc burning time on voltage and current. The thesis concludes with summary of the results of each individual measurement and their presentation in the wider context.
Design of MV contactor for railway application
Pala, Lukáš ; Šimek, David (referee) ; Valenta, Jiří (advisor)
In the introduction a traction circuit is analyzed with different types of electric devices. The thesis describes power railway electric circuits, their loads and types of used contactors. Railway standards chapter summarizes requirements of standards for railway contactors. Follows literature focusing on power current switching and power switching devices design. Based on previous, a design procedure is developed for railway MV contactor in accordance with end-user and standards requirements. Thesis closes with pre-designing a railway contactor by calculating electrodynamic forces, heatflow and mechanical components.
Remanent magnetism of electromagnets of DC contactors
Horký, Jakub ; Píška, Jakub (referee) ; Šimek, David (advisor)
The master thesis is focused on a remanent magnetism of electromagnets of DC contactors. In the first part of the thesis deals with the formation of a magnetic field in different kinds of materials, description of their magnetization and sorting. The next part is focused on the principle and history of an electromagnet. Negative effects and remanent induction of the contactor are described in the end of the theoretical part. The second part is a practical part. First, the reaction times were measured on a pair of DC contactors. Using the obtained data, an electronic circuit was designed to minimize the difference in switching times of the given DC contactors.
Experimental Measurement Of Radial Temperature Distribution Of DC Arc
Šimek, David
The paper is focused on an electric arc spectroscopy diagnostics related to electric low voltage apparatuses. Measurement of radiation spectra of the electric arc burning between carbon electrodes with cooper admixture is presented. Cooper has a lot of suitable atomic spectra lines for calculation purposes. The problems connected with the measurements are discussed. The main part of the paper deals with a calculation of radial temperature distribution of the arc. Abel inversion was used to extracts the radial (2D) distribution from a one-dimensional projection measurement. Atomic lines database of National Institute of Standards and Technology was used as a spectral data source for the calculations.
Control of Low Voltage Contactor by calculation and measurement
Veselý, Matěj ; Šimek, David (referee) ; Bušov, Bohuslav (advisor)
The bachelor project deals with controlling mean parametres of low voltage contactor by calculation and measurement. Deals more specifically with calculation of the applied electrodynamic forces on the contactor's movable contact, the determination of the minimum compressive force on the contactor's movable contact and the design of the contactor trip system. It also deals with calculation of heating of the current-carrying path on contactor and its following check by measuring.
Design of DC electromagnet
Mayer, Aleš ; Bušov, Bohuslav (referee) ; Šimek, David (advisor)
This bachelor thesis deals with electromagnets and measurements on them. There is described the history of discovery of electromagnets, the principle of operation, their construction, and classification according to various criteria. More detailed descriptions of individual basic types are presented. The method of deriving the tensile force calculation is explained for DC as well as for AC electromagnets. There is a detailed description of the design process of a core DC electromagnet, which is then simulated in the FEMM program, and a 3D model with technical documentation is created in the Inventor program. The part also deals with measurement on electromagnets. More precisely, it is a measurement of static and dynamic tensile characteristics, measurement of electromagnets temperature rise. In the next part, transient phenomena and their measurements are explained, namely inrush current and switching overvoltage.
Assessment of the design of a small photovoltaic power plant for a family house and elaboration of its revision process
Kovaľ, Nikodém ; Šimek, David (referee) ; Veselka, František (advisor)
The bachelor's thesis deals with the assessment of a domestic photovoltaic power plant for a family house and the processing of its revision. At the beginning are explained the principle of conversion of solar energy into electrical energy, types of individual photovoltaic cells used in practice, methods of increasing the efficiency of photovoltaic modules, the most common failures of PV modules and methods of their detection. Furthermore, the assessed photovoltaic power plant is presented, its theoretically described components, graphical dependencies showing its production and the possibilities of increasing its production. The practical part of the work deals with the revision of the assessed PV plant and its documentation.
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.
Software for evaluation of data from CVVOZE laboratory
Petráček, Dominik ; Šimek, David (referee) ; Pikula, Stanislav (advisor)
The diploma thesis is focused on the innovation of partially user-unsuitable software which is used in the CVVOZE short-circuit laboratory for the evaluation of testing of switching and protection devices. The introductory part of the work presents a technical laboratory, which is used for research and development in the field of electrical devices with possibility of testing of short circuits and over-currents. At the first part of thesis, there is made a description of the technical laboratory. The following past is a chapter with basic introduction of tested devices and standard testing conditions of electrical devices in the laboratory. Then following a description of the original evaluation software is made and its shortcomings are pointed out. The practical part is devoted to the creating in LabVIEW, implementation and verification of the functionality of the new evaluation software.

National Repository of Grey Literature : 36 records found   1 - 10nextend  jump to record:
See also: similar author names
13 Simek, David
1 Šimek, D.
5 Šimek, Daniel
3 Šimek, Dominik
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