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Electronically commutated motor
Vykopal, Petr ; Melichar, Petr (referee) ; Vítek, Ondřej (advisor)
The main idea that lead to the development of EC (electronic commutation) motors is to remove from commutation motors, called DC (direct current) motors, the mechanical commutation system i.e. the cylinder brushes and the commutator that limits in most of the applications the longevity of direct current motors. The commutator is the source of electromagnetic interference and it limits the motor speed. At the same time it is required to keep the outstanding features of DC motors, mainly the multiple overload capacity, high starting torque, low time constant and small dimensions. Thesis introduces the problematic of electrically switched machines and their possible construction versions. Based on obtained findings there is performed an analytical calculation of EC-machine with classical stator (made with two grooves on pole and phase) and with segmental stator for given parameters. With the known parameters of the machines from personal design there were created models of both machine types, and the results obtained from the program FEMM were compared to those of analytical calculations.
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Design and analysis of three-phase induction motor
Svoreň, Jan ; Skalka, Miroslav (referee) ; Vítek, Ondřej (advisor)
This project is focused to projecting and analysing the three-phase induction machine. It starts with introduction to principle functions of electrical machines and their design issues. The main objective is to develop a method to calculate and analysis a smaller machine. The design involves the calculation of the main dimensions of the machine, the calculation of the number and dimensions of the rotor and stator grooves and calculation of the stator windings. Designed machine is analysed by calculation and finite elements method.
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Minimizing induction motor losses
Trn, Ondřej ; Cipín, Radoslav (referee) ; Vítek, Ondřej (advisor)
This bachelor thesis is aimed at reducing losses of three-phase induction motor. The first part deals with the construction and principle of engine operation. Another part of the thesis is focused on the calculation of asynchronous motor parameters according to technical documentation. Subsequently, the calculated parameters are verified using the Ansys RMxprt program. The third part of the thesis is focused on the detection of losses from the motor measurement. The last part focuses on engine adjustments to reduce losses.
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Design of a Magnetic Bearing for an Electrical Machine
Rúra, Dávid ; Vítek, Ondřej (referee) ; Bárta, Jan (advisor)
The current development in the field of electric machinery is focusing on high-speed electric machines. This opens also other fields related to high-speed machines. One of them are magnetic bearing systems. Tradition approach of using ball bearing brings a few problems in design dealing with friction at high speeds. Together with magnetic bearings, development is their control. Faster chips opened a new way of thinking of control and helped to evolve robust control loops. The biggest advantage of magnetic bearing is non-friction run and almost no maintenance. Compare to traditional ball bearing, a magnetic bearing system needs more space and in some applications could happen that the shaft will be twice as long. This problem can be solved designing complex system with motor and integrated magnetic bearing what leads to downsizing. In this master thesis, the design of magnetic bearing for 12kw, 45000rpm is discussed. It focuses on practical design and correlations between parameter selection. The analytical approach is used to sketch the design and optimization is done afterwards. Problem with an analytical design is that it doesn't cover all parasitic phenomenae and thus numerical modelling snd optimization are demanded. Also, the critical speed analyze is included in this thesis. The results of the work will be used for manufacturing prototype as an extension to the existing high-speed machine.
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Flux density measurement in electric machines
Hájek, Jan ; Vítek, Ondřej (referee) ; Janda, Marcel (advisor)
Magnetic induction is one of the basic variables. This quantity is mainly used in engines. Without a magnetic induction range of engines would not work. For example, for an asynchronous motor is the distribution of magnetic induction is very important. Measurement of cognition and values, such as magnetic induction, there's still the new findings, which are for this very important issue. Measured magnetic induction is not so easy matter. Manufacturers will attempt to make the best of magnetic induction meter. They include GAUSS / TESLAMETR model 7030 working on the Hall effect. In practice, it is possible to calculate the size of magnetic induction into the engine through programs designed for this purpose. These include ANSYS Workbench. This program is able to very accurately detect and simulate what size will have a magnetic induction. Show us the place where the magnetic flux density in the largest and the smallest engine. Evaluated using these results we can then design the engine so as to give the best characteristics and minimize losses.
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Electromagnetic analysis and modeling of a solid rotor induction machine
Bílek, Vladimír ; Vítek, Ondřej (referee) ; Bárta, Jan (advisor)
Tato diplomová práce se zabývá elektromagnetickou analýzou a modelováním asynchronního stroje s plným rotorem. Tato práce tedy zahrnuje literární rešerši na téma vysokootáčkových elektrických strojů s porovnáním s klasickými elektrickými stroji s převodovkou a popisem jejich výhod či nevýhod, rozdělení vysokootáčkových elektrických strojů s plnými rotory a srovnání jejich výhod či nevýhod, kde se tato práce nejvíce soustřeďuje na vysokootáčkové asynchronní stroje s plnými rotory a jejich použití v průmyslu. Dále se tato práce zabývá metodami výpočtu elektrických asynchronních strojů s plnými rotory. Proto jsou zde uvedeny a popsány metody výpočtu stroje mezi které patří analytické metody i metoda konečných prvků. Vzhledem k povaze elektrických strojů s plnými rotory je hlavně kladen důraz v této práci na výpočet stroje pomocí metody konečných prvků ve 2D prostoru s využitím korekčních činitelů konců plných rotorů, které jsou zde velmi detailně popsány a rozděleny. Na základě dostupné literatury je vypočítaný elektrický stroj s plným rotorem pomocí MKP analýzy. Elektromagnetický výpočet stroje je automatizován pomocí skriptu vytvořeného v Pythonu. Dalším hlavním cílem této práce je popis tzv. náhradních modelů, uvedení jejich výhod či nevýhod, použití v jiných průmyslových odvětvích a hlavně použití náhradních modelů na elektrický stroj s plným rotorem. S využitím náhradních modelů je dále optimalizovaný vybraný asynchronní stroj s plným rotorem a to pomocí programů SymSpace a Optimizer. Pro samotnou optimalizaci byly uvažovány 3 návrhy stroje, které byly na závěr mezi sebou porovnány a to hlavně z hlediska jejich elektromagnetického výkonu.
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Electric machines - education materials
Boháč, Karel ; Huzlík, Rostislav (referee) ; Vítek, Ondřej (advisor)
Semestral´s Thesis is oriented on practical consecution in calculating and derivation property of direct current machines. Guide reader by point elementary relations to correct result. Separately situations are completed with word description, pictures apposite actual condition of machine and animation of machine running.
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Calculation of 50kW permanent magnet synchronous motor
Šatava, Patrik ; Cipín, Radoslav (referee) ; Vítek, Ondřej (advisor)
This master’s thesis deals with a permanent magnet synchronous machine calculation. In the first part of the thesis, the synchronous machine in general is described. Knowledge of these machines is essential for the remaining parts of the thesis. In the next part, an analytical calculation process of a given permanent magnet synchronous machine is presented. The given machine had already been manufactured before the thesis assignment. The calculation is to be adapted to the given machine. This way the parameters of the calculated machine should match the reference machine. The accuracy of the calculation can then be evaluated. Furthermore, calculations of the machine using Ansys RMxprt and Ansys Maxwell 2D are presented. The calculations are then compared with data obtained by measurements performed on the given machine. In the last part of the thesis, a modification in the analytical calculation is made to reduce the inaccuracy of the calculation. The thesis is concluded by evaluating the results.
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Design and analysis of single-phase induction machine
Souček, Jiří ; Mach, Martin (referee) ; Vítek, Ondřej (advisor)
This thesis deals with the design issues of single-phase induction motors. The content is divided into several basic parts. The first chapter deals with the principle function of single-phase induction motors. In particular, the asymmetry of these machines discussed with regard to the importance of connecting the auxiliary stage and its character. The following part is devoted to the analytical calculation of specific single-phase two-pole motor. I analyzed two-pole motor because at that time there were not available data for six-pole motor from Siemens. The calculation is performed according to the literature, and the resulting parameters are then compared with the model of this motor created by RMxprt. There is model of six-pole induction motor created by Ansoft/Maxwell in third part. This model shows the influence of skew of the rotor slots on the torque of machine. Then I performed measurement of this motor and analyzed of results in the last part.
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Design of high speed induction motor 350kW, 40000r.p.m.
Karásek, Ladislav ; Vítek, Ondřej (referee) ; Ondrůšek, Čestmír (advisor)
This thesis deals with the problem of the high-speed electrical machines. In the introduction summary of the high-speed machines are discussed. Induction machine with squirrel cage winding and solid rotor is chosen as suitable solution for given requirements. The multiple types of designs of the induction machines with solid rotor and problematic areas are discussed. Main part of this thesis is an electromagnetic design of the machine with respect to mechanical stress. The designed machine is analyzed with the use of finite element method in ANSYS Mechanical and Maxwell software.
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