
Optimization of magnetic circuit of induction motor for frequency up to 210 Hz
Binek, Martin ; Cipín, Radoslav (referee) ; Vítek, Ondřej (advisor)
This master’s thesis first deals with the theory concerning induction motor. It briefly desbribes the construction of threephase induction motors, the generation of tractive force, power flow with loss distribution and also torque characteristic. In the next part an analytical calculation of the parameters of equivalent circuit for an existing induction motor with known dimensions is performed. After the calculation it is possible to find out the rated parameters of the motor, which makes it possible to further compare results with the values obtained by other methods. The next step was to create a model of the motor in RMxprt program, which is later also translated to ANSYS Maxwell 2D model. Simulations were carried out in both interfaces. As the next step the results obtained by the three methods are compared with measured values and also evaluated. The final part of the thesis focuses on the optimization of the magnetic circuit for higher frequencies. Efficiency of the modified induction motor is examined for higher frequencies using RMxprt Optimetrics and this procedure is performed for both default and alternative electrical steel materials.


Thermal Model of Induction Machine and its Practical Verification
Toman, Marek
This article deals with making of thermal models of electric machines using socalled thermal network. The first part of this article describes reasons why thermal models of electric machine should be used. In the second part the heat transfer basics and thermal network basics are described. The last part is focused on simulation of a thermal network of a specific induction machine and its verification of correct functionality by measurements.


Frequency Characteristic of the Induction Machine
Kroupa, Martin
The paper focuses on the induction machine as the transfer member and on its behavior in the frequency domain. The linearized mathematical model of induction machine is introduced and the issue of its frequency transmissions is discussed. Finally, the appropriateness of the motor use as diagnostic tool for analysis of timevarying load torque is mentioned.


Possibility of Increasing Efficiency of Induction Machines by Means of Combined Stator Winding
Schreier, Luděk ; Bendl, Jiří ; Chomát, Miroslav
The paper analyses two basic variants of the combined connection of the stator winding of an induction machine. The aim of the use combined winding is to suppress the selected groups of higher spatial harmonics of the current layer and induction in the air gap and the flux in the yoke and thus lower the losses and improve the efficiency. There are given differential equations for both the variants.On the basis of a numerical solution of these equations, the ability of the two variants to suppress higher harmonics has been shown. The validity of the equations has been verified by experimental measurement on a physical model of an induction machine with the stator combined winding.


Constrained Modeling of Induction Motor Using Physical Modeling and FEM
Trávníček, Tomáš ; Huzlík, Rostislav (referee) ; Vlach, Radek (advisor)
Tato práce řeší návrh komplexního modelu asynchronního stroje, pomocí něhož se dá stroj analyzovat. Model se skládá z dílčích modelů, které popisují asynchronní stroj z hlediska elektromagnetického, elektrického a tepelného. Elektromagnetický model je řešen pomocí metody konečných prvků v programu zvaném FEMM. Další výpočty jsou provedeny pomocí Matlabu. Tepelný model počítá s ustáleným stavem stroje v požadovaném pracovním bodě. Elektrický model je řešen pomocí náhradního schématu, ze kterého jsou odvozeny vztahy pro elektrické veličiny. Výsledný propojený model je naprogramován v Matlabu a slouží jako nástroj pro analyzování asynchronního stroje.


Noise suppression of six pole induction machine
Lexa, Jakub ; Janda, Marcel (referee) ; Ondrůšek, Čestmír (advisor)
This thesis deals with noise of electromagnetic origin of six pole threephases induction machine. Task thesis was rendering literature review. Analysis of the problem consists of various analytical calculations using Matlab and subsequent comparison of results with measured data on real induction machine. The last part of thesis is a summary of conditions for induction machine with low noise.


Analysis of damage to the rotor bars of induction machines
Henzel, Roman ; Michailidis, Petr (referee) ; Skalka, Miroslav (advisor)
This bachelor thesis deals with disorders of induction machines with focus on the failure or damage to the rotor bars or end rings. The work includes a literature research of the low resistance measurement, which can be used to determine the rotor bar resistance of the squirrel cage induction machine. The experimental measurement of the analyzed motor with the following conditions (shortcircuit, noload and load) is also includes. The magnetic model of the machine was described and created in MAXWELL and results were compared with the LabVIEW software (in order to verify the accuracy of the particular simulation). Analysis results evaluation of three phase squirrel cage induction machine with broken rotor bars was done.


Traction DC/AC inverter 2,5kW for an induction machine of an electric garden tractor
Krist, Petr ; Patočka, Miroslav (referee) ; Vorel, Pavel (advisor)
This thesis deals with the proposal of power 3phase DC/AC inverter for an induction machine of small garden tractor. It concerns the choice of a voltage level of DC link, dimensioning of the power circuit, drivers for power transistors, implementation of metering and protection and also processor driving. The whole thing ends at proposal of PCB in the software program called EAGLE and PCB manufacturing. So we also check if the theoretical calculations are correct and if the whole drive works.


Electromagnetic field calculation of Induction machine for different mechanical load
Hetflajš, Martin ; Kurfürst, Jiří (referee) ; Skalka, Miroslav (advisor)
This bachelor’s thesis deals with an analysis of the induction machine electromagnetic field distribution with real parameters. Whole analysis was done for three point of the mechanical load by finite element method in ANSYS. In the next part is described a basic theoretically research of the electromagnetic field and also preliminary survey of the numeric method for FEM. This thesis also contains an analysis of electromagnetic model of analyzed induction machine with detailed description of each analysis step and in conclusion the results summary was done.


Design and analysis of threephase induction motor
Svoreň, Jan ; Skalka, Miroslav (referee) ; Vítek, Ondřej (advisor)
This project is focused to projecting and analysing the threephase 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.
