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Optimization of the cooling of induction machines
Halfar, Ivo ; Dostál, Lukáš (referee) ; Janda, Marcel (advisor)
This master‘s thesis deals with problems of optimization of cooling in electrical machines. This work includes introduction to the theory of mathematical optimization and brief introduction to optimization problems. This thesis deals with using of program Ansys Workbench for the thermal analysis in electrical machines and optimization of their cooling. Thesis contains thermal analyse of specific asynchronous motor with the squirrel cage and optimization of its cooling.
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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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Design and analysis of high-speed induction motor
Klusáček, Jiří ; Ondrůšek, Čestmír (referee) ; Vítek, Ondřej (advisor)
Classical series production induction motors are usually adequate to most of the industrial application by range of rpm. For application requiring higher speed is traditionally used gearbox which is between motor and driven equipment. Nowadays, where are settings demands on efficiency operations and the most easily maintainance, so aim is to join driven equipment narrow with motors. When operating motors over 3000 rpm there are some proper problems. Generally, there is higher losses due to supply voltage from frequency converters and mechanically strength of rotor. This thesis provides a view on existing solutions of high speed induction machines. In the text there are mentioned options of using laminated rotor and solid rotor. Due to regard to angular speed of rotor there are mentioned the most important equations and knowledge, which are related to a mechanical strength of used materials and dimensions of machines. Later on is there mentioned groundwork, which when we are respecting them, we may improve the efficiency of machine. In this thesis is mentioned design, analyses and manufacturing process of high speed induction motor with solid rotor and copper layer at the surface. After that there are simulation of electromagnetic field through the use of finite element method in program FEMM. In the last chapter there are presented measured data of manufactured high speed motor and they are compared with calculations.
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Analysis and Optimisation Power Parameter of Small Induction Motors
Pařízek, Jiří ; Mach, Martin (referee) ; Hájek, Vítězslav (advisor)
This thesis deals with the asynchronous engines, describes their structure, principles, properties, use, and briefly describes the design of three-phase asynchronous motor. The first section describes the most common three-phase induction motor, the emergence of the rotating magnetic field and the basic relationships. The second part deals with asynchronous motors for specific applications, their design and features. The next section is an analysis engine borrowed from the electric company ATAS Náchod, and The last section lists ways to improve the basic parameters of induction motors designed and optimized engine.
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Unconventional Design of Internal Combustion Engines
Konečný, Tomáš ; Drápal, Lubomír (referee) ; Svída, David (advisor)
The content of bachelor thesis is to explore the possibility of replacing the traditional arrangement of crankshaft and timing mechanism in combustion engines. The aim of this work is to design the default parameters for the selected engine performance. After designing the default parameters are designed and created CAD models of basic engine components. Subsequently developed a basic overview of alternative concepts of internal combustion engines and elaborated a basic available analysis of the structure. In the conclusion of the thesis is evaluation of the results.
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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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Analysis of birth weight and losses in piglets
DULOVCOVÁ, Ivana
The aim of the theses was to evaluate the characteristics of reproduction of sows with focus on birth weight of piglets and losses of piglets. Forty-two litters were studied. The average number of piglets born alive was 12.38. The average percentage of stillborn piglets per one litter was 5.43, the percentage of mortality until the weaning was 27.8. The average birth weight of piglets born alive was 1.29 kg. Most of the piglets (51%) fell into 1.051.5 kg category with an average weight of 1.30 kg. The relationship between number of piglets born alive and their birth weight was r = -0,121. The average weight of stillborn piglets was 1.08 kg. The gestation period of gilts was 0.28 day shorter than the sow gestation period and they gave birth to 4.03 fewer piglets born alive than sows. The gilts showed a higher proportion of piglets' mortality until the weaning (the difference was 3.46%). The sows showed higher average weight of piglets born alive (the difference was 0.19 kg). The sows with longer gestation period (114 days) gave birth to 0.15 piglet born alive more than the sows with shorter gestation period (less than 113 days). The sows with shorter gestation period showed smaller proportion of stillborn piglets from all born piglets, the sows with longer gestation period showed smaller proportion of piglets' mortality until weaning. In deliveries longer than 8 hours 10.37 piglets were averagely born alive, which was 2.52 piglets less than for sows with deliveries shorter than 6 hours, or 2.6 piglets less than for the sows with deliveries from 6 to 8 hours. In deliveries shorter than 6 hours was the highest number of stillborn piglets. The highest mortality of piglets was until 24 hours after a birth (33%), 28% of piglets died the second day, 12% died the third day and 9% the fourth day. The mortality decreased noticeably from the fifth day after the birth.
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Possibilities of implementation the lean production in the choosen company
MALATÍNOVÁ, Lenka
The aim of this thesis work is to evaluate the functioning of the already established elements of lean production, analyze production effectiveness before and after the introduction of these elements in the choosen company. This thesis characterizes the production before the introduction of lean production and shows deficiencies in the production process. These deficiencies have been eliminated implementation of lean production on the line. Subsequently indicators are evaluated before and after the introduction of the lean production. The experiment participants explains the principle of push and pull, one-piece-flow or customer tact.An integral part of the implementation of lean manufacturing was 5S method. It was proposed posible improvements for enterprise . It was recommended to conduct thorough supplier evaluation and subsequent communication with them. Other recommendations focused on Kaizen management, which is a system for proposals to improve employees.
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