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Acceleration method of measuring electrical machines
Ředina, Ondřej ; Mach, Martin (referee) ; Červinka, Dalibor (advisor)
This thesis deals with the acceleration method of measuring electrical machines. The beginning of the work is dedicated to the description of standard loading methods, the description of the acceleration method and the analysis of losses in the electrical machine. Two speed modulations are selected: linear and sinusoidal. Each modulation requires a different procedure for determining the speed profile parameters. To apply the method, a diagram of the connection of the workplace is drawn and its optimization is carried out. Subsequently, the usability of the oscilloscope card is verified, which ensures the determination of the instantaneous frequency. Before the test itself, the moment of inertia is measured and the parameters of the speed profile are calculated. The acceleration method is supplemented by a full load test for a more detailed comparison of the results. The measured data almost coincide with the predicted values and trends.
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Evaluation of combine harvesters John Deere 670i and Claas Lexion 770
JURÁSEK, Martin
This bachelor thesis evaluates the John Deere 670i and Claas Lexion 770 combine harvesters in terms of cost, threshing quality, losses and area performance. The thesis describes the functions of the combine harvesters and their technological description and practical applications. The parameters calculated in the bachelor thesis are pre-harvest and harvest losses, area and weight performance, mass yield, travel speed, crushing quality, fuel consumption and fixed and variable costs.
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Switching loss reduction in the switch-mode supplies
Vašíček, Adam ; Vorel, Pavel (referee) ; Patočka, Miroslav (advisor)
The master's thesis covers in its first parts origins and consequnces of the switching losses, basic principles of the various resonant tanks and resonant DC/DC converters. Afterwards the innovative approach of the multiperiod modulation is presented. The main advantages of this kind of modulation include very wide zero current switching region and lowering the switching frequency as the output voltage decreases. In the remaining part of the thesis a prototype converter design is described.
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Energetic model of linear axis with ball screw and servodrive
Sládek, Vojtěch ; Tůma, Jiří (referee) ; Huzlík, Rostislav (advisor)
The aim of the thesis was to study the Energy Models of Linear Axes with Ball Screws and Servo Drives, to analyze the individual parts of the axis with respect to losses, the methodology of calculating the losses on the electrical part and the mechanical part of the drive and creating a complex algorithm that calculates the energy consumed for the specified motion. The thesis is divided into a theoretical and practical part, where the theoretical part is divided into the treatise on the electrical part of the axis and its losses and the part that deals with the mechanical part and its losses. The calculation is divided into the basic verification algorithm and the calculation on the given example. Each calculation is calculated for both linear acceleration and S-curve acceleration. For both types of acceleration, the result of energy and its course over time is also the waveforms of position, velocity, acceleration, angular acceleration, moments, powers, power, speed and currents over time.
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Calculation of optimum slip frequency of induction motor for minimisation of its losses
Bednařík, Václav ; Patočka, Miroslav (referee) ; Vorel, Pavel (advisor)
This master’s thesis focuses on the minimisation of losses by calculation of optimum slip frequency of induction motor. The next point of this master‘s thesis is supersaturation. Supersaturation must be solved for the size of losses, because of the effect that is cause of the losses, when current increases with saturation. However current is not increase proportionally with increasing saturation, but increases several times more. This problem is included in the calculation of the slip frequency. Optimum of slip frequency is solve for modified gamma model of induction machine. In the main point of this thesis is outlined the process, how the optimum can be found. With same process were already were found the equations, but they were too extensit. In the end is solved the optimum of slip frequency be minimum of the flux density.
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Family house in passive standard
Svoboda, David ; Jelínek, Petr (referee) ; Sedlák, Jiří (advisor)
The bachelor's thesis on a topic “The family house of standard passive” deals with the design of the house for family housing in accordance with applicable legislation. The house is designed in the Highlands on the edge of developing area Račerovice. The cellarless two-storey building is made of brick. The roof is according to local regulative plan made up of saddle-shaped truss system. The passive character of the house requires large glass areas on the south facade of the house and high-quality thermal insulation of the building envelope with minimal losses. The house is associated with a brick garage with a shed-roof.
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Efficiency Improvement of Small Induction Motors
Vilím, Martin ; Veselka, František (referee) ; Hájek, Vítězslav (advisor)
In this bachelor´s thesis I discuss about asynchronous engines in general, describe their construction and principle of operation, using. It also includes measurements of a specific motor and design engine. The first part deals with theprinciple of the engine options including the fundamental control over speed and torque. The second part deals with the measurement of the size of the searchengine and losses. The last part provides a proposal for a new induction motor.
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