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Design of fast magnetorheological damper piston group using selective laser melting technology
Vítek, Petr ; Růžička, Bronislav (referee) ; Strecker, Zbyněk (advisor)
The diploma thesis deals with the development of the magnetic circuit of Magnetoreological (MR) dampers with a short time response. To achieve a short response time, a shape approach was chosen whereby the geometry of the magnetic circuit was chosen to significantly eliminate the occurrence of eddy currents. The influence of structures on magnetic properties was first examined on a simpler toroidal core and then the optimization was subjected to the magnetic circuit of the MR damper itself. Geometry optimization was done using FEM simulations. The resulting geometry was made of pure iron using Selective Laser Melting technology (SLM). In addition, a MR damper was completed and its properties on air and with MR fluid were measured, which were then compared with previously developed rapid MR dampers. It has been found that the newly designed magnetic circuit achieves similar time responses as all other compared fast MR dampers and reaches a higher dynamic range than most of the compared variants. The proposed magnetic circuit also has a significantly reduced weight.
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Optimization of Control Algorithm of MR Damper
Strecker, Zbyněk ; Kotaba, Ondřej (referee) ; Ondrůšek, Čestmír (referee) ; Šindelář, Martin (referee) ; Mazůrek, Ivan (advisor)
This work deals with the usage of magneto-rheological (MR) damper in the semi-active car suspension. Semi-active suspension can improve ride comfort or tyre grip to the level, which cannot be achieved with the common passive setting of the damper. MR damper has however features, like time response of the controller with MR damper and the control range of the MR damper, which limit area of application. It was found out that especially the time response of the damper significantly influences the efficiency of semi-active algorithms. Current MR dampers with controllers are not capable of efficient control of the semi-active suspension. For proper design of semi-active suspension with MR dampers, the time response must be decreased. Therefore, a new PWM current controller was designed and verified. Also changes in MR damper design which eliminate eddy-currents in the magnetic circuit were proposed. The results of this work should contribute to the better design of semi-active suspension systems with MR damper.
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Optimalization of Induction Furnace Operation in foundry Vsetín
Trachta, Jiří ; Nowak, Stanislav (referee) ; Lázničková, Ilona (advisor)
The aim of this work is optimalisation of induction furnace in foundry for company PROMET FOUNDRY a.s. The company has two induction furnances. There are installed as identical construction. They have 2 modes of operation. First mode is founding and second mode is mode, where is temperature in maintain mode. Only one induction furnance can work in the founding mode at a time though. Inducion furnances are in the single-phase connection and they cause unbalance in the distribution network. Near the foundry there is a small network area whitch it is operated by company Zásobování teplem Vsetín a.s. The consumption of electrical energy in foundry so big, that in the year 2009 was made elaborate for Zásobování teplem Vsetín a.s. It was write at Laboratoře diagnostiky výkonů (Laboratory of performance diagnostics), which is a part of Electrotechnic Department at Technical Univarsity of Ostrava. The ordered study was named “Verification of causes of increased reactive energy consumption during transition from electricity delivery to electricity consumption”. The conclusion of this assignment confirms that in distribution network in the Jiráskova area in Vsetín there is unbalance of electrical energy and there is high part of reactive power. The next conclusion is crucial to find the customer who made the unbalance and to set relevant remedy. The last step will be the identification whether such device can actually be effectively balanced. It was subsequently proved that the Promet Foundry was causing the unbalance and that balanced consumption would be reasonable. Promet Foundry thus addressed Autel a.s. company with an inquiry to make a study of removing the causes of the unbalance which is caused by current induction furnaces operation at a minimum possible cost, least possible influence on the performance and minimum construction changes concerning the building. In this thesis there will be some topics. The result of which will be introducing of used heating technology, introducing of company and of effective plant performance and subsequent suggestions of possible unbalance removal or reactive power decrease. Several ways which are being implemented in the industry in order to balance consumption will be described. A suitable balancing plant will be subsequently chosen and its parameters will be calculated.
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Influence of skin effect, proximity effect and air gap on winding losses of HF inductors and transformers
Pitner, Tomáš ; Cipín, Radoslav (referee) ; Martiš, Jan (advisor)
The bachelor's thesis deals with power losses in the windings of high-frequency inductors and transformers. A detailed mathematical and qualitative analysis of the skin effect, proximity effect and leakage flux of air gap is performed, supplemented with the results of computer simulations using the finite element method. The thesis introduces analytical and numerical methods for calculating power losses in the windings of inductors and transformers and describes suitable measurement methods, which are further used in the thesis. For selected geometries of inductors and transformers, AC resistances of their windings are calculated using FEM and the results are compared with measurements on constructed prototypes. The winding geometries are also compared between each other.
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Design of synchronous linear motor
Jindra, Michal ; Mach, Martin (referee) ; Knebl, Ladislav (advisor)
Proposed thesis is focused on synchronous linear motor with an iron core, the design of an equivalent magnetic circuit and its calculation. The work describes the principle of a synchronous linear motor with permanent magnets, U-channel linear motor and a tubular linear motor. For these types of linear motors, the design solution is described and general advantages and disadvantages are mentioned. The losses generated in the motors are also described. The work introduces various methods of engine calculations that can be used for subsequent application to a particular type of motor. Subsequently, one of the methods is selected and used to calculate the motor. The last part is the evaluation and comparison of results.
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Magnetorheological shock absorber with short response time for train bogie
Šebesta, Karel ; Špalek, Petr (referee) ; Kubík, Michal (advisor)
The diploma thesis deals with the design of a magnetorheological damper with a short response time of the damping force for the bogie of a rail vehicle. The largest component, which slows down the response, is the eddy currents generated in the piston group of the MR damper. A rapid onset of damping force is achieved by using a shape approach in magnetic circuit design. The shape approach increases the distance that the eddy currents must travel, and therefore it helps to reduce them. The shape approach is realized by grooving the core and the shell of the MR damper. The proposed fast version of the MR damper is measured on a hydraulic pulsator and its results show a sufficient time response of the damping force. This response does not exceed 8 ms for the primary onset of the damping force. The new fast design of the MR damper combines the greatest advantages of the technology and enables to meet new requirements for damping elements in the rolling stock chassis.
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Skin effect in high-speed electrical machines.
Klíma, Petr ; Bárta, Jan (referee) ; Mach, Martin (advisor)
This master thesis deals with the suppression of the skin and proximity effects in high-speed machines. The first part summarizes the general knowledge of high-speed machines. The second part is devoted to the principle and possible suppression of consequences caused by skin and proximity effects. The third part shows the simulation results of models of a synchronous machine with permanent magnets. The results of these simulations reveal the consequences of skin and proximity effects. In addition, design measures are proposed to limit these and other undesirable phenomena to achieve the highest possible efficiency.
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Electrodynamic magnetic bearing design
Pavluš, Ondřej ; Janda, Marcel (referee) ; Rúra, Dávid (advisor)
High speed applications demands with a need for lower energy consumption lead to designing new types of bearings. In the last decades magnetic bearing, which would be able to obtain passive stable levitation using regular materials at room temperature, has been searched. This has lead to development of electrodynamic bearing based on eddy currents principle. Currently the electrodynamic bearings are still not fully explored and further research is needed. The aim of the work is to describe the theory about modern magnetic bearing, analysis and design of electrodynamic bearing according to given parameters. The finite element method is used for further analysis and evaluate behaviour of its properties.
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Eddy Current Probe Design and its Application on Aircraft Composite Structures
Boháčová, Marie ; Hájek, Karel (referee) ; Kopec, Bernard (referee) ; Mazal, Pavel (advisor)
This thesis deals with design of an eddy current transducer which enables non-destructive inspection of composite aircraft structures primarily carbon fiber reinforced plastic (CFRP) in areas of manufacture and maintenance. The design of the transducer is based on analytical-experimental approach and its electrical and mechanical parameters were optimized to ensure a good signal to noise ratio at the six composite samples. These samples contain artificial discontinuities in the form of various types of defects. These defects are simulating the various types of damage created in the aircraft structure, especially delamination or thickness changes of composite materials. The experimental measurements, data collection and non-destructive evaluation were performed during the period. The result of this work is functional eddy current probe, which is reliably able to detect some damage of the carbon composite structures to the depth of 3,9 mm.
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Non-destructive inspection methods of aircraft selected parts
Kníř, Jakub ; Třetina, Karel (referee) ; Trefilová, Helena (advisor)
Non-destructive testing (NDT) is a broad scientific field. This bachelor thesis provides an insight into NDT’s methods. It can’t embrace the whole field in any case because it’s needed to have knowledge from variety of other scientific fields in order to understand NDT completely. This thesis outlines basic testing methods and their usage for particular components of aircrafts. The thesis also includes a list of Czech and European standards relevant to the topic.
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