National Repository of Grey Literature 15 records found  1 - 10next  jump to record: Search took 0.00 seconds. 
Line protection against overload and short circuit
Konšel, Ladislav ; Vaněk, Jaromír (referee) ; Valenta, Jiří (advisor)
This work includes a theoretical treatise on the operation of electrical wiring for the overload and short circuit. This is mainly on thermal effects of over current and their influence on the properties of conductors and insulation. Work Includes links to determine the load current, depending on the properties of leadership and its surroundings. It also deals with the protection of conductors against overload and short circuit. The work includes measurements process of warming wires. Practical project of proposal circuit is created using SICHR. The project includes proposals of conductor’s sizes and safety components for both residential building and individual flats.
Calculation of heat and force field UniGear ZS1
Mokrý, Lukáš ; ABB, Drahomír Tůma, (referee) ; Dohnal, Petr (advisor)
The aim of my work is to describe high-voltage switchgear type UniGear 500R, which is part of UniGear switchgears family. I will focus on heating issue of one 500R unit and its parts during operation. Maximum values of this heating is limited by standards and can´t be exceed to ensure safe and reliable operation. That is why the heating tests are necessary part of designing and developing switchgears. Calculation will be made by two different ways. First is classic one-pole heating net method and second is numerical simulation in Solidworks flow simulation program. Except the theoretical description there will be presented also used 3D model and explanation of both method, used to calculation and simulation. Last point of this work is measuring of this type of switchgear and getting real data. The main point there is to compare measured values with values calculated and decide if is possible to simulate tests with appropriate accuracy. Then would be also possible to substitute the real test in laboratory, which costs many thousand crowns and takes lots hours of time. This work is collaborated with EJF division of ABB Company, where I am employed. Heating issues in this company is always on process, because of developing and improving of their products. So this work could be helpful in this field. ABB provides all materials needed, especially technical catalogues, 3D model and final values from laboratory measuring. Support from college faculty is mainly in study consultations and proposing of calculations making. In the end of work will be make final comparison and evaluation of achieved results.
Power supply of electrostatic separator
Broďák, Kamil ; Pazdera, Ivo (referee) ; Huták, Petr (advisor)
The diploma thesis focuses on the problems of electric power precipitators. Due to their current dominant position, the work concentrates on the sources of single phase transformers operating at the frequency of 50 Hz controlled by thyristors. The first part describes the electrostatic precipitator and its principle. This is followed by a brief insight into the proposal for an electrostatic precipitator. The work also explains the high voltage source that is divided into a transformer with a rectifier and into a control box with power circuits and control circuits that provide the power supplied by a transformer. The work also offers an explanation of the HV source system that operates at different conditions. The last part suggests a proposal for cooling cabinet including thyristors, for power line control box resources, for a supply line and a line to the transformer.
Model for the Cable Thermal Characteristic Calculation
Starý, Zdeněk ; Drápela, Jiří (referee) ; Orságová, Jaroslava (advisor)
The result of this assignment is the Model for the Cable Thermal Characteristic Calculation. Firstly, there is a prepared overview that is focused on the essential ideas of cable technology. The following part describes the simple possibilities of passaging the heat. Secondly,the physical essence of warming cables as well as the possibility to discover the methods how to calculate the warming cables are also mentioned in this task.There is an opportunity to find the methods for calculating the warming cables as well. The model was verificationed in the conclusion of my assignment. The measurement was done and the empirical results were compared with the results that were achieved by modeling.
Calculations of temperature fields on the model of induction motor
Koníček, Pavel ; Makki, Zbyněk (referee) ; Janda, Marcel (advisor)
The aim of this work is to get acquainted with the construction of induction motor, the calculation of temperature fields in the motor model in ANSYS Workbench and subsequent evaluation of the results for different operating conditions. There is provided a general description of the function and design of induction motor, a summary of sources of heat inside the engine design, heat transfer theory, the basic description of the finite element method and ANSYS Workbench description. Furthermore, comparison of temperatures measured on a real engine with the values obtained from the calculation program.
Reconstruction of discharging shakeout machine electric installation
Bednář, Vojtěch ; Blecha, Martin (referee) ; Pazdera, Ivo (advisor)
This Diploma work is concerned with the design of project documentation for discharging shakeout machine electric installation. This work continues in the Semestral project 2 in which the background of a new machine was made. Then, this work deals with the replacement of a switch room with required devices including the design of a new connecting cables and power streams. In the first part, the work deals with the control part of the device and the design of control and signal cables including the product documentation of the device. In the second part, the work deals with the proposal of building electro installation in which a new lighting and its use is described. The last part focuses on the coordination during the realization of a suggested device. In this part, all problems coming from the particular working procedures including a proposal of possible solutions are described. According to the project documentation and following realization, the documentation of final concept reflecting the real status of the device is described.
The use of molecular markers for the study of the impact of global change on fungal communities
Faltysová, Julie ; Baldrian, Petr (advisor) ; Koukol, Ondřej (referee)
Fungi are an essential part of life on Earth. Besides their main role in decomposition of organic matter, they belong among key symbiotic organisms and they take part in providing a range of ecosystem processes important for humankind such as primary production and with that related food availability or soil water regulation. For the study of fungal distribution, we often use a method called DNA metabarcoding which combines the use of specific molecular markers, most commonly universal fungal ITS, and high-throughput sequencing. The importance of the method has been rising in the current time of changing environment and it has helped us observe changes in fungal communities due to global change. It seems that primarily various climatic factors such as warming, changes in rainfall patterns and nitrogen deposition have strongly influenced community and fungal guilds composition. Consequently, these changes may potentially have an impact on ecosystem functioning so that their overall balance can be in threat. Key words: molecular markers, DNA metabarcoding, fungal community, warming, climate change, nitrogen deposition
Diagnosis warming selected parts of an electric machine
Prezbruchý, Martin ; Skalka, Miroslav (referee) ; Veselka, František (advisor)
This work is describing warming parts of an electric machine. In the first part, it is describing heat and temperature, its origin and radiation. Work is carrying on with the problems of heat origin in electric machines and in selected parts of an it. In the next part, the work is describing measurment and devides it in contact and contactless. The third part is dealing with electric machines and considers commutator motors. Work continues with practical part, which describes measurments on selected electric machine, includes calculations and graphs. After this part, work is dealing with temperature allocation in graphic interface and describes a 3D model production. In the conclusion, it is evaluating the measurment achievements and comparing the results of various used metods.
Calculations of temperature fields on the model of induction motor
Koníček, Pavel ; Makki, Zbyněk (referee) ; Janda, Marcel (advisor)
The aim of this work is to get acquainted with the construction of induction motor, the calculation of temperature fields in the motor model in ANSYS Workbench and subsequent evaluation of the results for different operating conditions. There is provided a general description of the function and design of induction motor, a summary of sources of heat inside the engine design, heat transfer theory, the basic description of the finite element method and ANSYS Workbench description. Furthermore, comparison of temperatures measured on a real engine with the values obtained from the calculation program.
Reconstruction of discharging shakeout machine electric installation
Bednář, Vojtěch ; Blecha, Martin (referee) ; Pazdera, Ivo (advisor)
This Diploma work is concerned with the design of project documentation for discharging shakeout machine electric installation. This work continues in the Semestral project 2 in which the background of a new machine was made. Then, this work deals with the replacement of a switch room with required devices including the design of a new connecting cables and power streams. In the first part, the work deals with the control part of the device and the design of control and signal cables including the product documentation of the device. In the second part, the work deals with the proposal of building electro installation in which a new lighting and its use is described. The last part focuses on the coordination during the realization of a suggested device. In this part, all problems coming from the particular working procedures including a proposal of possible solutions are described. According to the project documentation and following realization, the documentation of final concept reflecting the real status of the device is described.

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