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Axial magnetic bearing as a passive vibration damper
Polák, Robert ; Marada, Tomáš (referee) ; Pruša, Radomír (advisor)
The aim of the bachelor thesis is to design a mathematical model describing the damping effects of a prototype passive axial magnetic bearing. The prototype consists of three permanent axial magnets, the two outer ones are stators and are connected to the base, the middle magnet works as a rotor. Part of the work was a research on the topic of vibration dampers and their mathematical models. An experimental measurement of the dependence of the response of the axial deflection of the rotor on the axial load of the shaft was performed on a prototype bearing. The approach to creating a mathematical model was divided into two parts. First, the geometry of the bearing was simulated using the finite element method programme FEMM and the dependence of the force acting on the rotor magnet as a function of its deflection was determined. In the second part, the permanent magnets were replaced by conductive loops, for which the dependence of the magnitude of the power dissipation on their mutual deflection was compiled by the gradual derivation from the known equations. By connecting these two parts, an equation of motion was created for the middle loop or magnet. Using the Matlab and Simulink programs, this equation was simulated and then the results were compared with experimental measurements. Finally, the measurement and suitability of the mathematical model were evaluated.
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Design of magnetic bearing for pump
Pruša, Radomír ; Ondrůšek, Čestmír (referee) ; Huzlík, Rostislav (advisor)
The aim of this thesis is to design a magnetic bearing system for a pump. The use of magnetic bearings is based on the necessity of preventing the contact of the pumped fluid with a lubricant. The designed passive bearing consists of three axially polarized annular magnet using repulsive magnetic forces. The designed eight-pole radial bearing is formed by a laminated stator with salient poles and two-layer concentric winding. The rotor of the bearing is hollow because it also serves as a liquid supply of the impeller to centrifugal pump. The design of both bearings is based on the finite element method from the software ANSYS Maxwell. The results from simulating the axial bearing forces have been compared with the values obtained from experimental laboratory measurements. The component stress has been verified by implementing the function of stress analysis in Autodesk Inventor. The work includes research on the topic of constructing active and passive magnetic bearings.
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Passive axial magnetic bearing
Dostál, Patrik ; Štěpánek, Vojtěch (referee) ; Pruša, Radomír (advisor)
The goal of the bachelor thesis is to measure the characteristics of a passive magnetic bearing. The practical part of the thesis consists of two segments – experimental measurement of properties of a passive axial magnetic bearing and a simulation of this bearing using the finite element method in the FEMM application. The simulation also dealt with the effects of temperature on the bearing. It was discovered that high temperatures considerably lower the axial stiffness of the magnetic bearing. Other effects on the stiffness of the bearing were taken into consideration, especially the dimensions of used magnets and the distance between them. The values that were determined by the experimental measurement and the FEMM simulation were mutually compared. The analysed bearing was built for use in a seal-less centrifugal pump. The values determined by the simulation and the measurement were applied to practical use in pumps. A part of the thesis was concerned with a research on passive magnetic bearings. The research dealt with the principle of the bearings, their structure and their application.
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Axial magnetic bearing as a passive vibration damper
Polák, Robert ; Marada, Tomáš (referee) ; Pruša, Radomír (advisor)
The aim of the bachelor thesis is to design a mathematical model describing the damping effects of a prototype passive axial magnetic bearing. The prototype consists of three permanent axial magnets, the two outer ones are stators and are connected to the base, the middle magnet works as a rotor. Part of the work was a research on the topic of vibration dampers and their mathematical models. An experimental measurement of the dependence of the response of the axial deflection of the rotor on the axial load of the shaft was performed on a prototype bearing. The approach to creating a mathematical model was divided into two parts. First, the geometry of the bearing was simulated using the finite element method programme FEMM and the dependence of the force acting on the rotor magnet as a function of its deflection was determined. In the second part, the permanent magnets were replaced by conductive loops, for which the dependence of the magnitude of the power dissipation on their mutual deflection was compiled by the gradual derivation from the known equations. By connecting these two parts, an equation of motion was created for the middle loop or magnet. Using the Matlab and Simulink programs, this equation was simulated and then the results were compared with experimental measurements. Finally, the measurement and suitability of the mathematical model were evaluated.
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Passive axial magnetic bearing
Dostál, Patrik ; Štěpánek, Vojtěch (referee) ; Pruša, Radomír (advisor)
The goal of the bachelor thesis is to measure the characteristics of a passive magnetic bearing. The practical part of the thesis consists of two segments – experimental measurement of properties of a passive axial magnetic bearing and a simulation of this bearing using the finite element method in the FEMM application. The simulation also dealt with the effects of temperature on the bearing. It was discovered that high temperatures considerably lower the axial stiffness of the magnetic bearing. Other effects on the stiffness of the bearing were taken into consideration, especially the dimensions of used magnets and the distance between them. The values that were determined by the experimental measurement and the FEMM simulation were mutually compared. The analysed bearing was built for use in a seal-less centrifugal pump. The values determined by the simulation and the measurement were applied to practical use in pumps. A part of the thesis was concerned with a research on passive magnetic bearings. The research dealt with the principle of the bearings, their structure and their application.
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Design of magnetic bearing for pump
Pruša, Radomír ; Ondrůšek, Čestmír (referee) ; Huzlík, Rostislav (advisor)
The aim of this thesis is to design a magnetic bearing system for a pump. The use of magnetic bearings is based on the necessity of preventing the contact of the pumped fluid with a lubricant. The designed passive bearing consists of three axially polarized annular magnet using repulsive magnetic forces. The designed eight-pole radial bearing is formed by a laminated stator with salient poles and two-layer concentric winding. The rotor of the bearing is hollow because it also serves as a liquid supply of the impeller to centrifugal pump. The design of both bearings is based on the finite element method from the software ANSYS Maxwell. The results from simulating the axial bearing forces have been compared with the values obtained from experimental laboratory measurements. The component stress has been verified by implementing the function of stress analysis in Autodesk Inventor. The work includes research on the topic of constructing active and passive magnetic bearings.
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