Dissertations / Theses on the topic 'Rotor windings'

Thesis (PhD)--Stellenbosch University, 2012.
ENGLISH ABSTRACT: In this dissertation a new type of electrical machine, a Radial Flux Air-Cored Permanent Magnet machine with a Double-sided Rotor and utilising concentrated, non-overlapping windings, is proposed. The concept of the Double-sided Rotor Radial Flux Air-Cored Permanent Magnet machine, or RFAPM machine for short, was derived from the Double-sided Rotor Axial Flux Air-Cored Permanent Magnet (AFAPM) machine. One of the problems that AFAPM machines experience, is the deflection of the rotor discs due to the strong magnetic pull of the permanent magnets, especially with double-sided rotor machines. The main advantage of a RFAPM machine over a AFAPM machine is that the rotor back-iron is cylindrically shaped instead of disk shaped. Due to the structural integrity of a cylinder, the attraction force between the two rotors does not come into play any more. The focus of this dissertation is on a thorough analytical analysis of the Double-Sided Rotor RFAPM machine. With the RFAPM being an air-cored machine, the feasibility to develop a linear, analytical model, to accurately predict the radial flux-density and hence the induced EMF in the stator windings, as well as the accurate calculation of the developed torque of the machine, needed to be investigated. The need for a thorough analytical examination of the Double-Sided Rotor RFAPM machine stemmed from the need to reduce the blind reliance on Finite Element Modelling (FEM) software to calculate the back-EMF and torque produced by these machines. Another problem experienced with the FEM software was to obtain accurate torque results. Excessive ripple torque oscillations were sometimes experienced which took a considerable amount of time to minimise with constant refinement to the meshing of the machine parts. Reduction in the mesh element size unfortunately also added to the simulation time. The requirement for an accurate analytical model of the RFAPM machine was also necessary in order to reduce the amount of time spent on successive FEM simulation to obtain the optimum pole arc width of the permanent magnet in order to minimise the harmonic content of the radial flux-density distribution in the the stator windings. In this dissertation, the use of single-layer and double-layer, non-overlapping, concentrated winding for the RFAPM machine is also investigated. It was decided to include a comparison of these two non-overlapping winding configurations with a “hypothetical” concentrated, overlapping winding configuration. This would allow us to gauge the effectiveness of using nonoverlapping winding with respect to the reduction in copper losses as well as in the reduction in copper volume. It would also allow us to investigate the extent of how much the developed torque is affected by using non-overlapping windings instead of overlapping windings.
AFRIKAANSE OPSOMMING: In hierdie proefskrif word ’n nuwe tipe elektriese masjien, ’n Radiale-vloed Lugkern Permanent Magneet Masjien met ’n dubbelkantige rotor en nie-oorvleuelende Windings voorgestel. Die konsep vir die Radiale-vloed Lugkern Permanent Magneet Masjien, of RVLPM vir kort, is afgelei vanaf die Dubbelkantige Rotor, Aksiale-vloed Lugkern (AVLPM) masjien. Een van die probleme wat met AVLPM masjiene ondervind word, is die defleksie van die rotorjukke as gevolg van die sterk aantrekkingskragte van die permanente magnete, veral in dubbelkantige rotor masjiene. Die hoof voordeel wat die RVLPM masjien inhou bo die AVLPM masjien, is die feit dat die RVLPM se rotorjukke silindries is in plaas van ronde skywe. As gevolg van die strukturele integriteit van ’n silinders, speel die aantrekkingskrag van die permanente magnete nie meer ’n rol nie. Die fokus van die proefskrif gaan oor die deeglike analitiese analise van die dubbelkantige RVLPM masjien. Weens die feit dat die RVLPM masjien ’n lugkern masjien is, is daar besluit om ondersoek in te stel na die moontlikheid om ’n lineêre, analitiese model vir die masjien op te stel waarmee die radiale-vloeddigtheid, teen-EMK asook die ontwikkelde draaimoment vir die masjien akkuraat bereken kan word. Die behoefde aan ’n akkurate analitiese model vir die dubbelkantige rotor RVLPM masjien is om die blinde vertroue te elimineer wat daar in Eindige-Element Modellering (EEM) sagteware gestel word om die teen-EMK en ontwikkelde draaimoment van die RVLPM masjien uit te werk. ’n Verdere probleem wat daar met EEM sagteware ondervind is, is die akkurate berekening van die ontwikkelde draaimoment. Oormatige rimpel draaimoment ossillasies is soms ondervind wat heelwat tyd geverg het om te minimeer, deur voortdurende verfyning van die EEM maas in die verskillende dele van die masjien. Soos die maas egter kleiner word, verleng dit die simulasie tyd van die EEM aansienlik. Nog ’n rede vir ’n akkurate analitiese model van die RVLPM masjien, is om vinnige metode te verkry om die optimale permanente magneet pool hoekwydte te verkry, wat die minste Totale Harmoniese Vervorming (THV) in die radiale-vloeddigtheidsdistribusie in die statorgebied sal veroorsaak, sonder om herhaaldelike EEM simulasies te loop. In die proefskrif word die gebruik van enkellaag en dubbellaag, nie- oorvleuelende, gekonsentreerde wikkelings vir die RVLPM masjien ook ondersoek. Daar is besluit om hierdie twee nie-oorvleuelende windingskonfigurasies met ’n “hipotetiese” gekonsentreerde, oorvleuelende windingskonfigurasie te vergelyk. Dit behoort ons in staat te stel om die doeltreffendheid van nie-oorvleuelende windings te bepaal, met betrekking tot die afname in koperverliese asook die afname in kopervolume. Verder sal dit ons in staat stel om ook mate waartoe die ontwikkelde draaimoment deur nie-oorvleuelende windings beïnvloed word, te ondersoek.

The organic materials used for stator winding insulation are subject to deterioration from thermal, electrical, and mechanical stresses. Stator winding insulation breakdown due to excessive thermal stress is one of the major causes of electric machine failures; therefore, prevention of such a failure is crucial for increasing machine reliability and minimizing financial loss due to motor failure. This work focuses on the development of an efficient and reliable stator winding temperature estimation scheme for small to medium size mains-fed induction machines. The motivation for the stator winding temperature estimation is to develop a sensorless temperature monitoring scheme and provide an accurate temperature estimate that is capable of responding to the changes in the motors cooling capability. A discussion on the two major types of temperature estimation techniques, thermal model-based and parameter-based temperature techniques, reveals that neither method can protect motors without sacrificing the estimation accuracy or motor performance. Based on the evaluation of the advantages and disadvantages of these two types of temperature estimation techniques, a new online stator winding temperature estimation scheme for small to medium size mains-fed induction machines is proposed in this work. The new stator winding temperature estimation scheme is based on a hybrid thermal model. By correlating the rotor temperature with the stator temperature, the hybrid thermal model unifies the thermal model-based and the parameter-based temperature estimation techniques. Experimental results validate the proposed scheme for stator winding temperature monitoring. The entire algorithm is fast, efficient and reliable, making it suitable for implementation in real time stator winding temperature monitoring.

Heat transfer inside rotating coolant channels have a significant impact in design of gas turbine airfoils and other rotating components such as generator windings.  The effects of the Coriolis acceleration and centrifugal buoyancy have a significant impact on heat transfer behavior inside such rotating coolant channels due to the complex flow patterns of coolant.  Detailed heat transfer knowledge greatly enhances the designers\' ability to validate numerical models of newly designed channels. A rotating experimental rig was designed and built to model scaled up coolant channels at speeds up to 750 rotations per minute (rpm).  A camera is mounted onto the rotating test section and a transient liquid crystal technique is used to measure detailed heat transfer coefficients on a surface of interest.  The experimental set-up is innovative, as it involves no surface heating of the test section, very little instrumentation beyond a few thermocouples and a spray coating of thermochromic liquid crystals on the test surface.  To validate the test rig and the experimental method, multipass coolant channels with rib turbulators, large diameter radially outward channels with rib turbulators, and jet impingement cooling schemes are studied during rotation.  90deg, W, and M-shaped rib enhancements are studied and detailed heat transfer measurements clearly capture the heat transfer enhancement mechanisms with and without rotation.  Jet impingement schemes with single and double rows, normal and off-angle jets, and a cross flow outlet condition are all studied under rotation.  Non-rotating studies are also performed for baseline comparisons to rotating conditions.  Large aspect ratio, diverging channels with dimple and rib turbulators are studied in a stationary condition.  Results for all different test geometries show good comparisons with published studies indicating that the rotating rig and experimental method are valid.  Jet impingement schemes produce higher heat transfer compared to the two-pass channels with ribs, however pressure losses are significantly higher.  The fewer the jets and H/d=1 produces the highest pressure losses with no significant gain in heat transfer.  Off angle jets at H/d=1 produces very high pressure losses with no heat transfer advantage.  A final study with radially outward coolant channels is performed with the highest rotation speeds.  The structure, test section, and camera are thoroughly designed to withstand the exceptional g-forces.  Heat transfer in the radial channels with and without rotation show very little effect of rotation due to the small rotation number.
Ph. D.

The thesis theme is the design of 3 MW high-speed permanent magnet synchronous motor. The work is divided into several parts, and contains the information given on the topic. The first part lists trends and new technologies of high-speed electric machines, and the issues and construction of high-speed synchronous machines are also listed here. In the second part, the machine is analytically designed from the specified values, which is then modelled in the RMxprt program. In the penultimate part, the engine is simulated by programs that are included in the ANSYS Electronics Desktop package, they are RMxprt and Maxwell. The modified engine model in RMxprt is simulated using defined formulas and then converted to Maxwell 2D, where the engine is simulated using the finite element method. In the last part, the results from the analytical calculation are compared with other high-speed machines. In addition, the results of simulations from RMxprt and Maxwell were compared in the last part.

Insulating sheets, impregnants and encapsulation materials commonly used for winding insulation offer low thermal conductivities. This leads to an increased heating of the winding of electrical machines and to the existence of hotspots. The electromagnetical utilization of the machine has to be reduced with respect to the allowed maximum winding temperature. In this paper, the development and experimental investigation of novel polysiloxane composites with ceramic fillers are presented. The materials are tested by means of impregnated and encapsulated samples of a round-wire winding as well as the main insulation of electrical steel sheets and laminated cores. Numerical models are implemented for determining the equivalent thermal conductivity of the winding compound comprising the enameled wire and the impregnant. Based on the example of a permanent-magnet synchronous machine with outer-rotor in modular construction, the potential for increasing the electromagnetical utilization is shown.

This master´s thesis treats of all asynchronous motor. The project is about type and distribution motors, about differences between three-phase and single-phase machines and efficiency. In one of the chapters describes a particular type of engine with all the parametersfrom the manufacturer. This engine is completely analyzed and it is measured in detail. Then the project deals with the division, the calculation of losses and subsequent possibilities to increase the efficiency of induction motor. In the last chapter is calculation of single-phase motors, based on the engine produced.

This work is dedicated to increasing the effectiveness of a particular draft induction motor, which was before the change and subjected to laboratory measurements according to EN60034 - 2-1, an analytical calculation of the losses and the overall efficiency and analysis program RMxprt. The first part focuses on the analysis of measurement data, measurement of partial loss in the machine and overall efficiency. In the second chapter, losses and efficiency calculated analytically, in the first case using the links in the professional literature dealing with the design of electric motors and in the second case by a program for the rapid design of rotating electrical machines, RMxprt program. At the end of this chapter all parameters are obtained measurements and calculations are compared. The third chapter is devoted to the calculation of losses and the resulting efficiency machines in a computer program, in which I gradually adopted changes to increase the efficiency of electrical machines. It also shows the calculation of the new dimensions of the stator and rotor slots. In the fourth chapter, the preparation of documentation for the production of a new two-layer winding for the current machine, while preserving the original dimensions of stator slots. The last part is devoted to the analysis of measurement data on the supplied asynchronous motor with a newly designed stator winding. In conclusion then discussed the results of work.

The master's thesis deals and introduces a single-phase inductions machines, the principle of operation, types of design and operating conditions. This thesis includes analysis of individual losses in the machine and reduce the possibility of different ways. After a theoretical proposal for reducing losses are measured by mass-produced single-phase induction machine. Further machine modifications proposed for reducing losses in the stator windings and designed a prototype machine with the adjustment of the magnetic circuit to reduce iron losses made by ATAS elektromotory Nachod a.s. The results are supplemented by a simulation using software Maxwell RMxprt and finite element method (FEM). Finally, they are compared to each machines modifications mainly in terms of energy consumption.

In this thesis, the feasibility to integrate an brake disc and electric machine is investigated. In wheel motors (IWMs) have several advantages, such as saving space in the vehicle, individual and direct control at the wheels and the absence of a mechanical transmission. However, today’s IWMs are heavy and, thus, negatively affect the driving performance of the vehicle due to the increase of the unsprung mass. By integrating an already existing part in the wheel, this increase of the unsprung mass can be minimized. The brake disc manages high temperatures, a significant wear in rough environ-ment, which puts high demands on the rotor. The second part of the machine, the stator, will be significantly affected by the high temperatures of the rotor. The temperatures of the stator are transferred by convection, conduction and radiation from the rotor or brake disc. Liquid cooling of the stator back is analyzed as a potential solution for handling the high temperatures. In order to analyze the feasibility of the concept, thermal, electric and mechanical modelling has been used. The evaluation whether it is possible or not to integrate the brake disc has been with regard to the results of weight, cost, thermal tolerance and electric performance.
I detta arbete undersöks möjligheten att integrera en bromsskiva med elmaskin. Hjul-motorer har flera fördelar, bland annat sparas utrymme i själva bilen, individuell kontroll samt drivning av hjulen utan mekaniska transmissioner. Men hjulmotorer som kan användas idag väger oftast så pass mycket att den odämpade massan ökar kritiskt och köregenskaper av fordonet då blir lidande. Genom att integrera en befintlig del i hjulet kan ¨okningen av odämpade massan minskas. Att använda bromsskivan som rotor, kräver att denna tål temperaturer ¨over 500◦C samt påfrestningar och slitage som en vanlig mekanisk friktionsbroms måste uthärda. Den andra delen av maskinen, statorn kommer även denna att påverkas av de höga temperaturerna av bromsskivan som kommer ledas via konvektion, konduktion och strålning. Möjligheten att kyla statorn med vätska och om detta är tillräckligt undersöks. För att analyserna genomförbarheten av projektet har termiska, elektriska och mekaniska modeller använts. Resultaten har analyserats där maskinens vikt, kostnad, termisk tålighet och elektrisk prestanda har legat till grund för bedömningen om lösningen; att integrera en broms-skiva med elmaskin är rimlig eller ej.

This master's thesis considers by single-phase asynchronous motor. The first part discuss about construction, principle of operation and basic parameters of this motor type. It also discussed the emergence of torque and torque characteristics of the different types of engines. The second part explains the basic ways of obtaining grip moment including outline the principles of functions particulars constructions types, which is produce in practice. In the third part is minutely analyse single-phase asynchronous motor with auxiliary phase and permanently conect capacitor, including method of assign size of a capacitor. Fourth part section provides the principles of the procedure for calculating basic parameters of the single asynchronous motor with auxiliary phase. At the last part is accomplished a calculation of single-phase asynchronous motor with permanently conect capacitor at auxiliary phase including comparation with already manufacturing motor.

Hydropower research is often perceived to be an old and exhausted field of study but with ageing equipment and the need for more intermittent operation caused by an increased share of other renewable energy sources new challenges lie ahead. The main focus of this dissertation are the electromagnetic forces resulting from nonuniform air gap flux, whether it be caused by rotor eccentricity or a faulty field winding. Results are predominantly obtained from measurements on an experimental generator and numerical simulations. With the computational capacity available today it is possible to numerically analyse physical phenomena that previously could only be studied with analytical tools. Numerical models can also be expanded to encompass more than one aspect of generator operation in coupled field-circuit models without model complexity surpassing computer capability. Three studies of unbalanced magnetic pull, UMP, in synchronous salient pole generators constitute the main part of this thesis. The first is a study of how parallel stator circuits affect the unbalanced magnetic pull caused by rotor eccentricity. Depending on the relationship between the geometry of the separate circuits and the direction of the eccentricity it was found that parallel circuits could reduce the UMP substantially. Secondly, an investigation of the effect of damper winding configuration on UMP was performed. The results showed that damper winding resistivity and the distance between the damper bars in a pole determine the effectiveness of the damper winding in reducing the UMP. Simulations of a production machine indicate that the reduction can be substantial from damper windings with low resistivity. The third study analyses the consequences of field winding interturn short circuits. Apart from a resulting rotating unbalanced magnetic pull it is found that the unaffected poles with the same polarity as the affected pole experience an increase in flux density. In a fourth article a new stand still frequency response, SSFR, test method including measurements of damper winding voltage and current is presented. It is found that the identified models are capable of predicting the stator to damper transfer function both with and without the damper winding measurements included.

This thesis focuses on the analysis of the dynamic behavior of the load from the measurement of stator currents of induction motor. Work is sorted from basic engine failures equations, mathematical models, types of signal processing, simulation and measurement. The practical part deals with the design of the motor model in Matlab Simulink, the simulated and the measurement of the pump BETA 12 YC On the Department of Fluid Engineering Victor Kaplan. Use appropriate types of signal processing evaluate the results. The aim of this work is to analyze the dynamic changes of the load.

The possibility to save energy in synchronous machines operation by dismissing d-axis damping bars and surrogating them with active excitation current control in sectored field winding is proved. In particular a way to recover the energy of rotor oscillations during power regulation is shown by means of a studycase generator whereas a self-starting machine is analytically and numerically designed in view of its next construction and test. Principal design requirements and limits for both applications are presented and discussed.

Cette thèse est dédiée à la conception optimale de la machine synchrone à rotor bobiné modulaire sans balais pour les systèmes embarqués. Cette machine est basée sur une structure POKIPOKITM développée par Mitsubishi Electric Coopération avec les convertisseurs de puissance intégrée pour augmenter la capacité de tolérance aux défauts. L'analyse électromagnétique est utilisée pour étudier les différentes machines synchrones à rotor bobiné et donc, pour sélectionner la structure qui offre la meilleure tolérance aux défauts et les performances les plus élevées. D’abord, le choix des nombres de phases, d’encoches et de pôles est un point critique. Ensuite, quelques machines sont analysées et comparées selon les critères tels que la densité de couple, le rendement, l'ondulation de couple. La machine avec 7 phases, 7 encoches et 6 pôles est alors choisie. Cette machine est ensuite comparée à la machine synchrone à aimant permanent monté en surface. Le résultat démontre que la machine synchrone à rotor bobiné modulaire sans balais possède le potentiel de remplacer la machine synchrone à aimant permanent dans notre application parce qu’elle présente des performances similaires avec une capacité de tolérance aux défauts élevée. Dans un second temps, une fois la structure 7phases/7encoches/6pôles choisie, cette machine est optimisée en utilisant NOMAD (qui est un logiciel d'optimisation de boîte noire) afin de minimiser le volume externe sous les contraintes électromagnétiques, thermiques et mécaniques. Comme ce problème d'optimisation est extrêmement difficile à résoudre, quelques relaxations ont été effectuées pour tester les différents algorithmes d'optimisation : fmincon (de Matlab) et NOMAD. Nous remarquons que NOMAD est plus efficace que fmincon pour trouver des solutions à ce problème de conception où certaines contraintes sont calculées par des simulations numériques (ANSYS Maxwell ; code éléments finis). En utilisant la méthode NOMAD basée sur l’algorithme Mesh Adaptive Direct Search, nous obtenons des résultats optimaux qui satisfont toutes les contraintes proposées. Il est nécessaire de valider ce design optimisé en vérifiant toutes les contraintes par des simulations électromagnétiques et thermiques en 3D. Les résultats montrent que le couple moyen obtenu par la simulation en 3D est inférieur à la valeur souhaitée. Par conséquent, en augmentant la longueur de la machine, une nouvelle machine corrigée est ainsi obtenue. Nous observons que les pertes de fer obtenues en 3D sont plus élevées qu'en 2D en raison du flux de fuite dans la tête de bobinage. En prenant les valeurs des pertes analysées par la simulation en 3D, la température de surface de la nouvelle machine analysée par la méthode Computational Fluid Dynamics est plus élevée que celle calculée dans l’optimisation. Enfin, un prototype de machine est construit et quelques tests expérimentaux est réalisés. Le résultat montre que la force électromotrice à vide a une forme d'onde similaire par rapport à la prédiction numérique en 3D et la différence de couple statique maximum entre les tests expérimentaux et les simulations par éléments finis en 3D est faible
This thesis is dedicated to the design and the optimization of modular brushless wound rotor synchronous machine for embedded systems. This machine is constructed based on POKIPOKITM structure with integrated drive electronics. Finite element analysis based optimization becomes more popular in the field of electrical machine design because analytical equations are not easily formalized for the machines which have complicate structures. Using electromagnetic analysis to comparatively study different modular brushless wound rotor synchronous machines and therefore, to select the structure which offers the best fault tolerant capability and the highest output performances. Firstly, the fundamental winding factor calculated by using the method based on voltage phasors is considered as a significant criterion in order to select the numbers of phases, stator slots and poles. After that, 2D finite element numerical simulations are carried out for a set of 15 machines to analyze their performances. The simulation results are then compared to find an appropriate machine according to torque density, torque ripple and machine efficiency. The 7phase/7-slot/6-pole machine is chosen and compared with a reference design surfacemounted permanent magnet synchronous machine in order to evaluate the interesting performance features of the wound rotor synchronous machine. In the second design stage, this machine is optimized by using derivative-free optimization. The objective is to minimize external volume under electromagnetic, thermal and mechanical constraints. Given that an accurate finite element analysis for machine performance takes a long time. Moreover, considering that the average torque can be obtained by simulating the model with only four rotor positions instead of one electric period, optimization strategy is proposed to reduce computational time and therefore, obtain a fast convergence ability by defining relaxed problems which enable minimizing the external volume of the machine under only several constraints such as average torque, torque ripple and copper losses. By testing relaxed problems, two different optimization methods (NOMAD and fmincon) are compared in order to select an appropriate method for our optimization problem. Using NOMAD method based on Mesh Adaptive Direct Search, we achieve optimal results which satisfy all of the constraints proposed. In the third design stage, all constraints are validated by 3D electromagnetic and thermal simulations using finite element and computational fluid dynamics methods. The 3D results show that the average torque obtained is lower than the desired value. By increasing the length of the machine, a new corrected machine is thus obtained. It can be observed that the iron losses obtained in 3D are higher than that in 2D due to the leakage flux in the end-winding. Then, the machine temperature is analyzed by using ANSYS Fluent. Note that the surface temperature is higher than that calculated in the optimization and the coil temperature is 8.48°C higher than the desired value (105°C). However, some dissipation by the shaft and the bearings of the machine are expected to reduce the machine temperature. Finally, a machine prototype is built and some experimental tests are carried out. The results show that the electromotive force has a similar waveform compared to 3D prediction and the difference of the measured and predicted maximum static torques is small

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Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior
Electrical Motors transform electrical energy into mechanic energy in a relatively easy way. In some specific applications, there is a need for electrical motors to function with noncontaminated fluids, in high speed systems, under inhospitable conditions, or yet, in local of difficult access and considerable depth. In these cases, the motors with mechanical bearings are not adequate as their wear give rise to maintenance. A possible solution for these problems stems from two different alternatives: motors with magnetic bearings, that increase the length of the machine (not convenient), and the bearingless motors that aggregate compactness. Induction motors have been used more and more in research, as they confer more robustness to bearingless motors compared to other types of machines building with others motors. The research that has already been carried out with bearingless induction motors utilized prototypes that had their structures of stator/rotor modified, that differ most of the times from the conventional induction motors. The goal of this work is to study the viability of the use of conventional induction Motors for the beringless motors applications, pointing out the types of Motors of this category that can be more useful. The study uses the Finite Elements Method (FEM). As a means of validation, a conventional induction motor with squirrel-cage rotor was successfully used for the beringless motor application of the divided winding type, confirming the proposed thesis. The controlling system was implemented in a Digital Signal Processor (DSP)
Motores el?tricos transformam energia el?trica em energia mec?nica com relativa facilidade. Em algumas aplica??es particulares, necessita-se de motores el?tricos para trabalhar com flu?dos sem contamina??o, em regime de altas velocidades, em condi??es in?spitas, ou, ainda, em locais de dif?cil acesso e ? profundidade bastante consider?vel. Nestes casos, os motores com mancais mec?nicos, cujo desgaste ocasiona a necessidade de manuten??es, n?o s?o adequados. Uma solu??o poss?vel para este problema adv?m de duas alternativas: motores com mancais magn?ticos, que t?m o inconveniente de aumentar o comprimento da m?quina, e motores-mancais, que agregam compacidade. Motores de indu??o t?m sido cada vez mais utilizados em pesquisas, pois conferem maior robustez aos motores-mancais comparados a esses tipos de m?quinas constru?das com outros motores. As pesquisas j? realizadas com motores-mancais de indu??o utilizaram prot?tipos, cujas estruturas do estator e/ou rotor foram modificadas, diferindo em grande parte dos motores de indu??o convencionais. ? objetivo deste trabalho, estudar a viabilidade do uso dos motores de indu??o convencionais para a aplica??o de motores-mancais, apontando os tipos de motores dessa categoria que mais se ad?quam. O estudo utiliza o M?todo dos Elementos Finitos FEM. Como comprova??o, um motor de indu??o convencional com rotor gaiola de esquilo foi utilizado com sucesso para a aplica??o de motor-mancal do tipo enrolamento dividido, ratificando a tese proposta. O sistema de controle foi implementado em um Processador Digital de Sinais DSP

This thesis deals with the possibility of using the finite elements method for the analysing of synchronous permanent magnets machines. The aim of this work is to discuss the possibility of the machine design more effectively with using the finite elements method and Maxwell software for the simulations. On the created parametric model, simulations were performed according to master thesis assignment. The aim of this work is to determine induced voltage, iron losses, machine inductances and make a permanent magnets demagnetization analysis. From simulations results the machine efficiency is calculated. The parametric model was used for the optimization of selected parameters. From results of optimization new dimensions of permanent magnets was obtained. Machine efficiency was increased by new permanent magnet material and optimized design.

Permanent magnet synchronous machine (PMSM) are widely used in many industrial applications. This thesis starts with familiarization with the properties and structure of each type of synchronous machines with permanent magnets. Subsequently there are described properties and possible division of AC winding types. Afterward analytical designs of four machines with two different types of winding were realized. These designs were compared by means of simulations using the RMxprt program and their properties were subsequently verified by method of finite element using the Maxwell 2D program. Evaluation and comparison in terms of utility properties for all designs of machines were performed at the conclusion of this thesis.

The master´s thesis deal with the thesis of a single-phase induction motor that is more and more used all over the world. Its aim is assembling the information about this type of motor and its calculation. The content of the first part is the theoretical analysis of a single-phase induction motor and acquirement ways of the stroke moment. Than the work contains a project of basic schema of the single-phase induction motor with an auxiliary phase. The practical part is devoted to an elaboration of demonstration example of the single-phase induction motor with concrete parameters calculation, its method was projected before. Than there is practising successived measuring on the motor of the same parameters made firm EMP s.r.o. Slavkov by Brno in this part. In the conclusion there is the evaluation of the whole process with reached results.

This project deals with increasing efficiency of one phase induction motor with permanent split capacitor. We can whole thesis divide into two parts, the first one is basic and the second is interested in analysis and measurement. First part handles with construction of single phase induction motor, explanation of function principle, start and run of motor. Calculating of efficiency including type of losses, which reduce efficiency. Second part concerns analysis losses including moment load characteristic, motor measurement while rotor is locked, with no load operation, measuring mechanical and additional losses. Further there will be measured useful values for creation model for simulation (reactance of windings etc.). Than will be the model created in ANSYS Maxwell with module RMxprt. After analytic calculation in RMxprt and using Finite Element Method (FEM) load characteristics will be compared together. This comparison gives us information about accuracy of model for simulation. Simulation and measurement will be carried out on another engine with high quality ferromagnetic material used for magnetic circuit of motor. Further will be done simulation of motor with modifications shown in previous chapter for high efficiency.

This diploma thesis deals with the possibility of using a concentrated winding in an induction motor and the use of copper bars in a rotor cage. The first part of the thesis explains the basic theoretical knowledge of the operation and principle of the induction machine. In this theoretical part we will learn what is actually a concentrated winding and how it is placed on the stator. The second part is focused on the analytical design of the machine with classical distributed winding and with concentrated winding. The third theoretical part is an introduction to the issue of influencing the motor harmonics. The last final part of the thesis shows differences in operational properties of designed machines.

Hydropower maintains its position as the most important source of renewable electric energy in the world. The efficiency of large hydropower plants is unsurpassed, and after more than hundred years of development, the technology is mature and highly reliable. While new hydro resources are currently being developed in Asia and South America, most European countries go through a phase of intense refurbishment and upgrading of existing plants. Challenges faced by the hydropower industry include a knowledge transfer to new generations and the adaptation of unit designs to meet new operational requirements. As with all branches of engineering, the use of computerized design tools has revolutionized the art of hydropower plant design and the analysis of its performance. In the present work, modern tools like coupled field-circuit models and semi-analytic permeance models are used to address different aspects of electromagnetic analysis of generators in large hydropower plants. The results include the presentation of a mathematical model that uses concepts from rotating field theory to determine the air-gap flux density waveform in a hydroelectric generator. The model was succesfully used to evaluate armature voltage harmonics and damper bar currents at no-load and load conditions. A second study is concerned with the importance of losses due to rotational fields in core loss calculations. It is found that dynamic and rotational effects typically increase the total core loss estimates with about 28% in large hydroelectric generators. In a third study, linear models for the calculation of salient pole shoe form factors at an arbitrary level of magnetic loading are presented. The effect of the damper winding configuration on the damping capability of salient-pole generators is then evaluated in a separate study. The predicted impact of the coupling between damper cages on adjacent poles on the damping torque production is verified in a set of experiments.

Master thesis deals with design and construction of the most widely used engines currently. Overall, it is divided into five chapters, the first chapter deals with constructional features of various three-phase asynchronous motors, the second chapter briefly paid attention to single-phase motors. The next chapter focuses on the specific engine types, which differ from standard induction motors in its design implementation. This is an engine with full rotor, hysteresis, linear and with shaded field. Although asynchronous motors are considered the most reliable machines work in imperfect conditions, it leads to frequent breakdowns. This is covered in chapter four. Based on the findings from previous chapters the fifth chapter includes a preliminary draft of the asynchronous motor with a full rotor. The last chapter is devoted to the measurement on functional models.

L'apparition dans les années 80 de semi-conducteurs fonctionnant aux fréquents industrielles avec de très faibles pertes a relancé l'étude des machines supraconductrices. L'association d'un induit supraconducteur statique avec un inducteur à aimants permanents conduit à des moteurs couples robustes. Ces structures hybrides très compactes et légères sont destinées aux systèmes embarqués qui nécessitent de forts couples massiques. Les essais menés sur une maquette de petite puissance ont validé le concept et les calculs théoriques. Pour tirer des conclusions sur cette structure hybride originale il convenait de concevoir, construire et tester une machine de taille significative. L'objet de cette thèse est l'étude de définition de ce démonstrateur de 150 kW à 400 tr/min. En vue de la construction, une étude des matériaux utilisés a été menée, notamment sur les composites en fibres de verre. Les contraintes thermiques expliquent la structure, dite air, des moteurs hybrides. Après une réflexion sur la réalisation de l'induit et l'inducteur, la machine a été calculée à partir d'un programme d'optimisation pour maximiser le rendement rapport au couple massique. Le démonstrateur présente de bonnes caractéristiques, principalement limitées par la cryogénie. De nombreuses simulations numériques avec le programme d'éléments finis flux ont permis de mieux apprécier les caractéristiques de la machine. Enfin, l'extrapolation à de plus forts couples donne une idée du seuil de compétitivité de ces moteurs hybrides et gains possibles en termes de poids, encombrement et rendement. Une comparaison avec une solution classique a été menée pour la chaîne de traction du T. G. V.

The magnetic field analysis by MKP and magnetic probe project deals with magnetic field analysis of asynchronous machine cross section. This analysis is written in detail along with the necessary theory of asynchronous machine and the ANSYS program. The magnetic field of selected machine is measured by magnetic probe and results are compared with calculation. The next part of thesis is draft of device for the magnetic field analysis.

Documentos apresentados no âmbito do reconhecimento de graus e diplomas estrangeiros
Induction machines are one the most important electrical equipment in industrial plants and manufacturers. They have a great variety of features, structures and performance. So, proper and secure protection design and fault detection are important issues. The induction machines are divided into two categories as squirrel-cage and wound-rotor types. Due to many advantages of squirrel cage motors (e.g. simplicity, lower cost, less maintenance and etc.) they are the most common choice for industries. However, wound rotor induction motors have their own applications, where they have high start-up torque for industries such as hoist, cement and steel ones. According to the fault destructive effects on induction motors, fault detection and the related region identification in early stages are the most important protection criteria. In this thesis, monitoring of the air-gap flux and measuring the rotational magnetic field distortion and asymmetricity caused by stator or rotor Turnto-Turn fault is regarded as the main parameter to detect such faults. To achieve such aim, some simple flux sensors are installed in the specified stator slots, so that each phase equipped by two flux sensors aligned with the magnetic axis of the related coils. In motor healthy condition, passing fluxes from the corresponding sensors are equal, which results in the identical induced voltages in them and then difference of them (i.e. Δ ) is equal to zero. In case of stator or rotor winding Turn-to-Turn fault, Δ will no longer be zero due to rotational magnetic field distortion and such phenomenon is the main criterion to detect the faulty condition and discriminate the stator or rotor winding faults, in this thesis. To demonstrate the capability of this method, not only the simulation results but also the experimental test results have been used. The ability to detect and discriminate rotor and stator winding Turn-to-Turn fault, faulty phase detection in the cases of stator faults, low processing burden and high sensitivity in the face of permissible voltage unbalance and mechanical load variation are the undeniable advantages of this method, which can be pointed out.