National Repository of Grey Literature 114 records found  beginprevious104 - 113next  jump to record: Search took 0.01 seconds. 
Blízká fotometrie
Škoda, Jan ; Sumec, Stanislav ; Baxant, Petr ; Krbal, Michal ; Pavelka, Tomáš
Paper describes deficiencies of conventional method for luminous intensity curve measuring and it brings comparison with newly used methods of near field photometry. There is also presented demonstration measurement of problematic type of luminaire with use of near field Photometry.
Bezdrátová svítidla
Krbal, Michal ; Škoda, Jan ; Štěpánek, Jaroslav ; Baxant, Petr
The development in the field of lighting technology is focused on new technologies, light sources with higher efficiency and better lighttechnical parameters and the development of luminaires, especially in the field of design and small light sources. The efficiency of light sources is associated with converting of electricity into the light in the entire process chain, including the efficiency of power wires and ballast systems. It can be stated that the losses in the power supply line and wires path are less important in comparison with the actual process of internal energy conversion in light sources. Since the beginning of use of electrical energy for the conversion to light the conductor and wires are used. The luminaires are fixed to one place and move with them is limited to a small place. The solution may be a wireless power and energy transfer. The result of this solution is the possibility of placing the luminaires anywhere in a defined space without wires and cables. The disadvantage is significantly lower efficiency of energy transfer and strong electromagnetic interference, which may exceed the limits of EMC and affect the operational of other electrical equipments. Questionable issue is the exposure of human body to RF fields unnecessarily. This paper deals with the search for potentially useful applications of wireless powering in lighting.
Creation of Knowledge Database for Lighting Technology with the Possibility of Expert Query Processing
Krbal, Michal ; Sokanský, Karel (referee) ; Gašparovský, Dionýz (referee) ; Baxant, Petr (advisor)
This presented thesis is focused on the complex description of creation the database system for the lighting. The important static and dynamic parameters of light sources and luminaires are listed in the first part of thesis. These parameters are complemented by the measured values and their relationships. The next chapters of thesis are focused to description of obtained parameters, structural design, historical and expected development of individual representatives of light sources. In the following sections are described current state of used data formats of luminaires and the possibilities for describing of light sources. The database systems are created as a result of this thesis. These databases are used for collecting, sorting, searching and sophisticate comparison of the parameters of light sources and luminaires.
Wind power generation and energy accumulation possibilities
Krbal, Michal ; Mastný, Petr (referee) ; Drápela, Jiří (advisor)
The goal of this bachelor’s thesis is to inform about conditions of running and the character of running of the wind power plants and about the suitable storage systems for the possibilities of time invariableness of power supply. For these reasons is immediately in the first chapter of the thesis described state of using wind power plants in The Czech republic and other countries in Europe which produce electric power. Description of individual functional parts is important mainly from the point of electrician conversion of kinetic energy of wind to electric energy with help of the electric power generator with the highest efficiency and without need for maintenance. It is necessary to know those functional parts of the power wind to be able to design appropriate storage system. The output electric power is very variable at time, mainly output voltage, because wind energy is variable too. The characteristics of the wind power plants as output voltage, frequency and their switching graded at time have to in accordance with requirements of the electricity supply systems not to disturb the stability or even collapse of the electricity supply system which would lead to serious economic consequences. These predicaments can be prevented with precise meteorological forecast or by using the acceptable storage system with small acquisition and operating costs, requirements to safeness and long service life, low weight and high efficiency of conversion of energy. The storage systems are classified into centralized and decentralizing systems with requirements to dynamic running and running time. To fulfil these conditions it is essential to choose acceptable and accessible locations with year lasting qualities of wind, which are being checked in advance using measurement and mathematical calculations.
Methods of ignition spark gaps
Pekárek, Dominik ; Štěpánek, Jaroslav (referee) ; Krbal, Michal (advisor)
This thesis deals with methods of spark gap ignition. The thesis describes spark gap ignition by external electrode, by Rogowski electrode and by lasers. Advantages and disadvantages of these methods are also discussed. In the final part of the thesis there is described experiment with high voltage spark gap.
Photobiological safety of light sources and lighting systems
Štěpánek, Jaroslav ; Krbal, Michal (referee) ; Škoda, Jan (advisor)
The thesis deals with the problems of the photobiological lamp and lamps systems safety. It is divided into theoretical and practical parts. The theoretical part touches the basic knowledge concerning the eye and vision, eye and skin diseases caused by excessive exposure to non-ionizing radiation. And besides that there are described the sources of light causing the possible exposure and further more it includes the methodology of measurement and evaluation of photobiological safety. The practical part investigates a measurement of the spectrum of light sources. The measured data are evaluated according to the methods mentioned in the theoretical part.
Partial discharge
Macek, Vratislav ; Krbal, Michal (referee) ; Toman, Petr (advisor)
The main subject of this diploma’s thesis is the creation of laboratory task on the partial discharge. The thesis is made up of two parts: theoretical and practical. In the theoretical part there are information about partial discharge. One of them is classification partial discharge by type, effects of partial discharge in insulation systems, parameters to assess the quality of electrical insulation of power systems and measurement techniques. Further part is user’s manual for measurement instrument. In practical part is created laboratory task on problematic of the partial discharge measurement. It is demonstrative measure of partial discharge with the aim of understanding problematic of partial discharge, calibration and noise.
Influence of Change in Frequency of the Supply Current to the Operational Parameters of the Discharge Light Sources
Kuptsov, Alexander ; Škoda, Jan (referee) ; Krbal, Michal (advisor)
The master’s thesis is devoted to exploiting of gas-discharge lamps and their dependence on frequency of the supply current. The first part describes the theory of discharge, its types and properties, terms of its origin, and ways of its exploitation. The second part concerns electrical ballast systems of gas discharge light sources, inductive (reactive) and electronic ballasts, principles of their functioning, advantages and disadvantages, and the comparison of their properties. The following chapters deal with low-pressure and high-pressure gas-discharged lamps, compare their properties and describe exploitation of fluorescent lamps. Before conducting laboratory experiments the influence of frequency of the supply current on different properties of gas-discharge lamps was described. Besides, simulation of basic electric parameters of high-pressure gas-discharged lamps was implemented in the program SIMULINK/MATLAB. As a result, the received graphs show the dependence of current, voltage and electric power on time. Another simulation included building of dynamic current-voltage characteristics at various frequencies of the supply current. Preparations for the laboratory experiment and the experiment itself were implemented. Compact and tube low-pressure fluorescent lamps were measured. The received graphs show the influence of change in frequency of the current on the operational parameters of the discharge light sources.
Influence of Change in Frequency of the Supply Current to the Operational Parameters of the Discharge Light Sources
Kuptsov, Alexander ; Škoda, Jan (referee) ; Krbal, Michal (advisor)
The master’s thesis is devoted to exploiting of gas-discharge lamps and their dependence on frequency of the supply current. The first part describes the theory of discharge, its types and properties, terms of its origin, and ways of its exploitation. The second part concerns electrical ballast systems of gas discharge light sources, inductive (reactive) and electronic ballasts, principles of their functioning, advantages and disadvantages, and the comparison of their properties. The following chapters deal with low-pressure and high-pressure gas-discharged lamps, compare their properties and describe exploitation of fluorescent lamps. Before conducting the experiment we have described the influence of frequency of the supply current on fluorescent tube lamps. Preparations for laboratory measuring have been also implemented. During the experiment the two types of lamps have been analyzed, the results of the research are summed up in the conclusion.
Efficiency of Converting Electric Energy to Light in Current Light Sources
Krbal, Michal ; Pavelka, Tomáš (referee) ; Baxant, Petr (advisor)
The goal of this diploma’s thesis is to inform about present development of light sources, new technologies and about achieved parameters of these light sources. The thesis is mainly directed to describe efficiency of transformation electric energy to light at single types of light sources. There are described the concrete technical parameters of sources quoted by manufacturers and the contructional solution of single types of light sources. There is created a graphic comparation of electrotechnical and light parameters of the light sources.

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