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1
Obiozor, Clarence Nwabunwanne. "Finite element analysis of a defective induction motor." Ohio University / OhioLINK, 1987. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1171672609.
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Levett, D. B. "Analysis and control of an induction motor." Thesis, University of Southampton, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370346.
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Liang, Darwin Tat Wai. "Simulation and analysis of induction motor drive systems." Thesis, Heriot-Watt University, 1993. http://hdl.handle.net/10399/1427.
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Zheng, Libo. "Analysis and control of five-phase induction motor drives." Thesis, University of Strathclyde, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.501695.
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Analysis and control of five-phase induction motor drives are investigated in this thesis. A vector model for five-phase induction motors is derived. Two distinct aspects related to multi-phase induction motor modelling are revealed and determination of the equivalent circuit parameters is explained from theoretical and experimental viewpoints. Modulation techniques for the five-phase voltage source inverter are developed, with both separate and simultaneous space excitation included. The analysis of five-phase induction motor drives is verified using a practical test rig. Indirect vector control applied to the first and third space harmonics, with separate excitation and simultaneous excitation, are experimentally assessed.
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Davidson, Innocent Ewean Agbongiague. "Performance analysis for a shaded-pole linear induction motor." Doctoral thesis, University of Cape Town, 1998. http://hdl.handle.net/11427/21326.
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Bibliography: pages 129-148.The induction motor remains the prime mover of present day industry with it's associated components in drive applications. In many such applications, fractional horse-power motors find ready use in small mechanisms where three-phase power supply is not available. In Southern Africa, these motors can be used is rural areas with simple reticulation systems, hence the renewed interest in the development of these low-power electrical motors, especially specialised models such as linear versions of such motors for special applications. This research is in the area of single-phase LIMs. The objective has been to model the shaded-pole LIM, in an attempt to enhance it's performance through improved design methods. This was carried out using an integrated analysis approach, involving circuital and field theory in the analysis of the practical motor, and computer simulation of it's equivalent model using the finite element method. Linear counterparts are possible for all the various forms of rotating electrical machines. All cylindrical machines can be 'cut' along a radial plane and 'unrolled' [32]. LIMs convert electrical energy directly into mechanical energy of translatory motion. Some advantages of linear version of induction motors are: they are gearless and often require minimal material thus minimising cost. While their scope of application are somewhat limited when compared to rotary versions, they do however give excellent performance in special situations where translator motion is required. However, the output power-to-mass and output power-to-volume of active materials ratio is reduced compared to rotary induction motors[45]. These disadvantages are caused by the large air-gap and the open magnetic circuit, which produces parasitical effects.
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Leedy, Aleck Wayne Nelms R. M. "Analysis of DC power systems containing induction motor-drive loads." Auburn, Ala., 2006. http://repo.lib.auburn.edu/2006%20Spring/doctoral/LEEDY_ALECK_32.pdf.
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Najjar, Mohamad. "Machine analysis : being a study of the application of the finite element method for solving the two-dimensional field of the single-phase shaded-pole induction motor." Thesis, University of Strathclyde, 1985. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21461.
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This thesis contains eight chapters, dealing with machine analysis and representation. A definition and a brief survey of previous investigation devoted to shaded-pole motors and the application of finite element method for solving the two-dimensional electromagnetic field is given in Chapter 1. An outline of the present investigation is also given. In Chapter 2, the experimental requirements and details of the equipment are given. This includes the techniques of recording the transient torque patterns and the method of measuring the complete torque-speed characteristics. The experimental methods for parameters determination are also mentioned. The finite element method is outlined in Chapter 3. This chapter deals also with the assumptions made, the formulation of the non-linear energy function, the solution of Poisson's equation and an example of a simple shape contianing 16 elements for illustrating the method. In Chapter 4, the computer program for the finite element is outlined. The iteration process and the numerical representation of the magnetization curve are mentioned. Application of the finite element method to the shaded-pole motor is also given. Calculation of parameters by finite element technique is given in Chapter 5. Self inductance is calculated using the concept of stored energy and the results of self and mutual inductances are tabulated. Basic performance equations of an electrical machine are derived in Chapter 6. Solution of the basic performance equations, by a step-by-step numerical method, is also given. In Chapter 7, the steady state performance equations are established in terms of harmonic currents and inductance coefficients. The flux linkages are evaluated by the approximated functions of mutual inductances. The electromagnetic torque is calculated from the stored energy in the magentic field. General conclusions and suggestion for further work are mentioned in Chapter 8.
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Guldemir, Hanifi. "Prediction of induction motor line current spectra from design data." Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287180.
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Wang, Chong Aerospace & Mechanical Engineering Australian Defence Force Academy UNSW. "Vibro-acoustic analysis of inverter driven induction motors." Awarded by:University of New South Wales - Australian Defence Force Academy. School of Aerospace and Mechanical Engineering, 1998. http://handle.unsw.edu.au/1959.4/38706.
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With the advent of power electronics, inverter-driven induction motor are finding increased use in industries because of applications that demand variable speed operations and because of the potential savings in energy usage. However, these drives sometimes produce unacceptably high levels in vibration and acoustic noise. A literature survey has revealed that while there has been intensive research on the design of inverters to minimize acoustic noise radiation from these drives, the vibro-acoustic behaviour of an induction motor structure has received relatively little attention. The primary objective of this research project, therefore, is to develop a general strategy/algorithm for estimating the acoustic noise radiated from inverter-driven induction motors. By using a three-phase, 2.2 kW induction motor, the vibration modes due to various structural components (such as the rotor, the stator/casing, the endshields and the base plate) of the motor structure were analysed by experimental modal testing. Results indicate that the vibration modes due to the rotor are only important at low frequencies. It has been found that the power injection method gives more accurate measurement of the damping of a motor structure than the modal testing and the time decay methods. If a point force excitation is used, then it is more accurate to measure the sound radiation efficiency than the power conversion efficiency for motor structures. The effect of three different inverter designs (an ideal ???almost sinusoidal??? controller and two commercially available PWM inverters) on the radiated acoustic power were assessed for both no-load and load conditions using sound intensity measurements conducted in an anechoic room. The results indicate that although the sound power level due to aerodynamic and mechanical noise increases at a rate of 12 dB per doubling of the motor speed, the electromagnetic noise dominates at low motor speeds and is still a significant noise source even at high motor speeds. For inverters with low switching frequencies, the radiated sound power level is almost 15 dB higher than the ideal case at low speeds and is relatively insensitive to the motor speed. For inverters that implement the random modulation technique, the change in the total sound power level with the level of the random modulation is very small but the tonal nature of the noise is greatly reduced. The vibration behaviour of a motor structure was modeled using the finite element method (FEM) and validated using the experimental modal testing results. It has been found that it is essential to model the laminated stator as an orthotropic structure. While the details of other structural components (such as the endshields, the teeth in the stator and the windings) are not so important, it is essential that they are incorporated into the structural model as simplified structures to account for their mass, stiffness and boundary conditions imposed on the motor structure. Based on this structural model, the radiated acoustic power for various operating conditions has been predicated using the boundary element (BEM) and the electromagnetic force calculated from an electromagnetic finite element model. The predicted results agree reasonably well with experimental measurements. Despite the success of the FEM/BEM approaches, they can be prohibitively expensive (in terms of computer resources required) to apply to large motors and high frequencies. Thus the feasibility of using a statistical method, namely, the statistical energy analysis (SEA), to estimate the radiated acoustic sound power from an inverter-driven induction motor has been examined. In order to carry out this analysis, analytical expressions for calculating the natural frequencies and radiation efficiency of finite length circular cylindrical shells (which are simplified models of the stator and casing of a motor structure) were firstly derived. The internal loss factors and coupling loss factors of the motor structure were determined experimentally using the power injection method. Then by introducing an equivalent surface mobility of circular cylindrical shells for the electromagnetic force, the vibration response and the acoustic noise radiated from each part of the motor structure were estimated. Results indicate that SEA method is potentially an efficient and effective tool in estimating the noise radiated from inverter-driven induction motors.
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Bal, Gungor. "Performance analysis of field-orientation controlled induction motor with parameter adaptation." Thesis, University of Strathclyde, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.392468.
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Al, Sayari Naji Mohammed Awn sulaiman. "Dynamic analysis of cage rotor induction motor using harmonic field analysis and coupling inductances method." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/dynamic-analysis-of-cage-rotor-induction-motor-using-harmonic-field-analysis-and-coupling-inductances-method(8c0aebfc-2d74-427e-9448-f9667a6ca099).html.
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The work presented in this thesis involves the development of a new analytical method for predicting the transient behaviour of squirrel cage induction motors subjected to pulsating mechanical loads such as a reciprocating compressor. The objective of this project is to develop analysis that will better inform the subsequent design method for determining the rating of industrial induction motors driving an oscillatory load. The analytical approach used to determine the transient response of the motor is based upon the harmonic coupling inductance method which is capable of accommodating any stator winding arrangement used in industrial motor designs. The analytical work described in this thesis includes the response of an induction motor subjected to a general oscillating load in terms of the damping and synchronous torque components. These torque components can be used to determine the additional system inertia required to limit the motor speed and current oscillations to predetermined levels. The work further identifies the motor-load natural resonant frequency and demonstrates the potential issues when driving a general oscillatory load at or close to this frequency. The analytical model was cross-checked using software modelling in Matlab for an industrial squirrel cage induction motor driving a selection of compressor loads. The simulation results were finally correlated with a detailed experimental validation in the laboratory using a squirrel cage induction motor connected to a permanent magnet synchronous motor controlled electronically to simulate general oscillatory load.
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Herwald, Marc A. "Control Design and Analysis of an Advanced Induction Motor Electric Vehicle Drive." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/32934.
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This thesis is about the development and performance enhancement of an induction motor electric vehicle drive system. The fundamental operation of the induction motor drive hardware and control software are introduced, and the different modulation techniques tested are described. A software simulation package is developed to assist in the control design and analysis of the drive system. Next, to establish the efficiency gains obtained by using space vector modulation in the improved drive system, an inverter with hysteresis current control is compared to the same inverter with space vector modulation in steady state and on separate driving profiles. A method for determining induction motor harmonic losses is introduced and is based on obtaining the phase current harmonics from sampled induction motor stator phase currents obtained. Using a semi-empirical loss model, the induction motor losses are compared between different pulse width modulation control strategies throughout the torque versus speed operating region. Next, several issues related to the robustness of the control design are addressed. To obtain good performance in the actual vehicle, a new method for driveline resonance compensation is developed and proven to work well through simulation and experiment. Lastly, this thesis discusses the development of a new method to compensate for the gain and phase error obtained in the feedback of the d-axis and q-axis stator flux linkages. Improved accuracy of the measured stator flux linkages will be shown to improve the field oriented controller by obtaining a more accurate measurement of the feedback electromagnetic torque.Master of Science
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Kanekal, Ramesh V. "Modeling, simulation and analysis of an indirect vector controlled induction motor drive." Thesis, Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/76443.
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Vector control technique is being widely used in ac motors drives for precise dynamic control of torque, speed and position. The application of vector control scheme to the induction motor drive and the complete modeling, analysis and simulation of the drive system are presented in this thesis. State space models of the motor and the speed controller and the real time models of the inverter switches and the vector controller are integrated to model the drive. Performance differences due to the use of PWM and hysteresis current controllers are examined. Simulation results of the torque and speed drive systems are given. The drive system is linearised around an operating point and the small signal response is evaluated.Master of Science
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Rehman, Habib-ur. "On the Analysis, Estimation, and Control of Field Oriented Induction Motor Drives." The Ohio State University, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=osu1380893074.
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Dalal, Dhaval B. "A novel parameter compensation scheme for indirect vector controlled induction motor drives." Thesis, Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/101179.
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Indirect vector controlled induction motor drives are gaining acceptance because they allow the induction motor to be controlled like a separately excited dc motor, i.e. they achieve decoupling of torque and flux producing currents. But, the effectiveness of these drives is lost as they are highly parameter sensitive. Studies have indicated that the decoupling of the torque and the flux channels is lost when machine parameters change with temperature, saturation, etc. Many schemes have been proposed to overcome these parameter sensitivity effects. But most of these schemes themselves are parameter-dependent and hence inapplicable to high precision control applications. A new parameter compensation scheme which uses air gap power equivalence for sensing parameter changes is developed in this thesis. It is shown that this scheme is independent of key motor parameters and requires no additional transducers for implementation.M.S.
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Goynuk, Yilmaz. "Development Of An Electrical Machines Analysis And Optimum Design Software Package." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609788/index.pdf.
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In this study, three different programs are developed for the analysis of the
three-phase induction motor, single-phase capacitor type induction motor
and switched reluctance motor. The programs are developed by using Pascal
and C++ programming languages. In the performance calculations of motors,
analytical methods are used and these methods are tested for accuracy.
These programs have also capabilities to design an optimum motor, which
meets a set of performance, material and manufacturing constraints while
minimizing the weight or any other defined objective function.
In addition, in this study, an optimization tool is used to obtain an appropriate
optimization method for the design of different types of motors.
The software is tested over different commercial motors. The results illustrates
that the performance calculations and optimization approach of the
programs lead to good results.
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Babu, Hareesh. "Finite-element analysis of an induction motor with inter-turn short-circuit faults." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-290082.
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Stator inter-turn short circuit (ITSC) faults are one of the common sources for induction machine failure affecting their reliable operation. In this thesis, a finite element (FE) model is developed to study the ITSC fault. The FE model is developed for a prototype induction machine that has the potential to emulate an ITSC fault in the stator. With the developed FE model of the prototype machine, a simulation study is performed to understand the behaviour of various electrical and magnetic quantities in time- and frequency-domain. The investigated quantities are potentially good signatures of the stator winding faults and they are therefore suitable to use in a condition monitoring system. The prototype machine with ITSC faults has been tested in an experimental setup and the results are compared to the simulation and also to analytical results. For the fault current it was found a good agreement between analytical results, FE simulations and experimental results. Moreover, the FE simulation results of the negative-sequence stator current amplitude present a minor mismatch with the analytical and experimental results. The reason for this mismatch is due to an inaccurate knowledge of the prototype machine geometrical parameters.Kortslutning mellan varven i en asynkronmotors statorlindning (ITSC) är en av de vanligaste källorna för fel som påverkar dess drifttillförlitlighet. I detta examensarbete utvecklas en finit-element (FE) modell för att studera ITSC- fel. FE-modellen är utvecklad för en asynkronmotorprototyp som kan emulera ITSC-fel. Med den utvecklade modellen utförs en simuleringsstudie för att förstå beteendet hos olika elektriska och magnetiska egenskaper både i tids- och frekvensdomän. Dessa egenskaper är goda indikatorer av statorlindningsfel och kan därför med fördel användas i ett tillståndsövervakningssystem. Prototypmaskinen har testats experimentellt och de erhållna resultaten jämförs med FE-simuleringen och analysresultaten. Det analytiska resultatet, FEM- simuleringarna och den experimentella utvärderingen uppvisade god överrensstämmelse vad gäller felströmmen. Dock finns det en mindre avvikelse när det gäller amplituden hos statorströmmens negativa fasföljd. Orsaken till denna avvikelse är att prototypmaskinens geometri inte är helt känd.
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Shaukat, Usman. "Performance Analysis of Unskewed Asymmetrical Rotor for LV Induction Motors." Thesis, KTH, Elektrisk energiomvandling, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-109726.
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This master thesis presents a comparative analysis of the starting performance and losses at rated operation for a 15 kW, 4-pole industrial induction motor, mounted with standard skewed, unskewed and unskewed asymmetrical die-cast aluminium rotors through measurements and simulations. It is a well-known fact that rotor skewing suppresses the synchronous torques at low speeds and also reduces the audible noise of the machine. However, the casting process results in a low resistive path between the rotor bars and the iron laminations, for skewed rotors, this promotes the flow of inter-bar currents. These currents, flowing between the rotorbars, increase the harmonic torques during a start and create additional losses at rated operation. For standard unskewed rotors, these losses are ideally zero, but these rotors may produce high audible noise. Studies have shown that rotors with asymmetrical rotor slot pitch can reduce the audible noise level in unskewed machines. By removing the skew, the inter-bar current losses are suppressed to a negligible level; ultimately increased machine efficiency is obtained. In this work the electrical performance is verified through measurements on the built prototypes. Direct-on-line starts and rated performance for motors with different rotor slot arrangements is simulated using 2D FEM tool FCSmek. The three prototypes are tested in the laboratory according to IEC 60034-2-1 standard and the simulation results are in good agreement with the measured results. An additional test for the measurement of high frequency delta connected stator winding currents for each prototype machine is also performed, in order to study the losses induced in the stator winding. Results have shown that by introducing the proposed asymmetry in the rotor slots, the synchronous torques at low speeds are suppressed effectively, thus, improving the starting performance of the asymmetrical rotor compared to the standard unskewed rotor. Additionally, a higher pull-out torque is obtained for the unskewed rotor motor compared to the standard skewed rotor motor. However, the losses were more or less re-distributed in the unskewed rotor motor, resulting in similar efficiency as the standard skewed rotor motor. One important observation is that; to capture the inter-bar current losses which are estimated to be 5.5% of the total losses, requires more accurate methods of measurements than the existing. And sufficient repeatability must be achieved; alternatively one should rely on statistical data obtained from measurements on several number of motors.
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Rylands, Naasef. "Condition monitoring of induction motors in the nuclear power station environment." Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/29686.
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The induction motor is a highly utilised electrical machine in industry, with the nuclear industry being no exception. A typical nuclear power station usually contains more than 1000 motors, where they are used in safety and non-safety application. The efficient and fault-free operation of this machine is critical to the safe and economical operation of any plant, including nuclear power stations. A comprehensive literature review was conducted that covered the functioning of the induction machine, its common faults and methods of detecting these faults. The Condition Based Maintenance framework was introduced in which condition monitoring of induction machines is an essential component. The main condition monitoring methods were explained with the main focus being on Motor Current Signature Analysis (MCSA) and the various methods associated with it. Three analysis methods were selected for further study, namely, Current Signature Analysis, Instantaneous Power Signature Analysis (IPSA) and Motor Square Current Signature Analysis (MSCSA). Essentially, the methodology used in this dissertation was to study the three common motor faults (bearings, stator and rotor cage) in isolation and compare the results to that of the healthy motor of the same type. The test loads as well as fault severity were varied where possible to investigate its effect on the fault detection scheme. The data was processed using an FFT based algorithm programed in MATLAB. The results of the study of the three spectral analysis techniques showed that no single technique is able to detect motor faults under all tested circumstances. The MCSA technique proved the most capable of the three techniques as it was able to detect faults under most conditions, but generally suffered poor results in inverter driven motor applications. The IPSA and MSCSA techniques performed selectively when compared to MCSA and were relatively successful when detecting the mechanical faults. The fact that the former techniques produce results at unique points in the spectrum would suggest that they are more suitable for verifying results. As part of a comprehensive condition monitoring scheme, as required by a large population of the motors on a nuclear power station, the three techniques presented in this study could readily be incorporated into the Condition Based Maintenance framework where the strengths of each could be exploited.
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Khodapanah, Mohammadali. "Critical analysis of determining induction motor operating power factor using measurement and estimation techniques." Thesis, Brunel University, 2018. http://bura.brunel.ac.uk/handle/2438/16199.
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Induction motors are the most used in commercial and industrial areas that consume the majority of generated electrical energy. The induction motors always create a low power factor. The low power factor not only create a penalty charge for industrial customers, but also produces energy losses in electrical systems. To prevent such issues, the users responsible to maintain the power factor to unity. Many researchers expressed that reactive power compensation by capacitors bank can be a substantial solution to maintain the power factor in the desired level at any loads, but providing the optimal reactive power still is a controversial topic. In the last decade, the power factor correction formula leads to obtain the optimal reactive power using measurement of input power and the operating power factor. However, measurement of these values synchronously create difficulties at any loading points. This research will examine a solution to determine the operating power factor of induction motors against input power from no-load to full/over-load conditions using measurement and estimation techniques. In this thesis, estimation techniques including Kriging, regression, neural network and support vector regression are implemented in three different induction motors with the size of 250 W, 10 HP and 100 HP in order to identify the best estimation technique. In these cases, the support vector regression technique with some inputs data determined the power factor and input power at every desired loading points with high accuracy. These estimated values contributed to obtain the optimal reactive power and so prevent under or over correction at any loading points.
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McKinnon, Douglas John Electrical Engineering & Telecommunications Faculty of Engineering UNSW. "Novel efficiency evaluation methods and analysis for three-phase induction machines." Awarded by:University of New South Wales. Electrical Engineering and Telecommunications, 2005. http://handle.unsw.edu.au/1959.4/21869.
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This thesis describes new methods of evaluating the efficiency of three-phase induction machines using synthetic loading. Synthetic loading causes the induction machine to draw full-load current without the need to connect a mechanical load to the machine's drive shaft. The synthetic loading methods cause the machine to periodically accelerate and decelerate, producing an alternating motor-generator action. This action causes the machine, on average over each synthetic loading cycle, to operate at rated rms current, rated rms voltage and full-load speed, thereby producing rated copper losses, iron loss and friction and windage loss. The excitation voltages are supplied from a PWM inverter with a large capacity DC bus capable of supplying rated rms voltage. The synthetic loading methods of efficiency evaluation are verified in terms of the individual losses in the machine by using a new dynamic model that accounts for iron loss and all parameter variations. The losses are compared with the steady-state loss distribution determined using very accurate induction machine parameters. The parameters were identified using a run-up-to-speed test at rated voltage and the locked rotor and synchronous speed tests conducted with a variable voltage supply. The latter tests were used to synthesise the variations in stator leakage reactance, magnetising reactance and the equivalent iron loss resistance over the induction machine's speed range. The run-up-to-speed test was used to determine the rotor resistance and leakage reactance variations over the same speed range. The test method results showed for the first time that the rotor leakage reactance varied in the same manner as the stator leakage and magnetising reactances with respect to current. When all parameter variations are taken into account there is good agreement between theoretical and measured results for the synthetic loading methods. The synthetic loading methods are applied to three-phase induction machines with both single- and double-cage rotors to assess the effect of rotor parameter variations in the method. Various excitation waveforms for each method were used and the measured and modelled efficiencies compared to conventional efficiency test results. The results verify that it is possible to accurately evaluate the efficiency of three-phase induction machines using synthetic loading.
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Astfalck, Allen Electrical Engineering Australian Defence Force Academy UNSW. "Analysis of electromagnetic force and noise in inverter driven induction motors." Awarded by:University of New South Wales - Australian Defence Force Academy. School of Electrical Engineering, 2002. http://handle.unsw.edu.au/1959.4/38671.
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This thesis is part of a major research project to analyse vibro-acoustic characteristics from variable speed inverter driven induction motors (VSIDIM). The overall projects??? aimed at providing a better understanding of the mechanisms of sound generation from electromagnetic origins and developing a numerical model to predict the sound power emitted from a VSIDIM. The scope of this thesis is to assess experimentally the effect of various controller strategies on the radiated sound power and to develop a finite element method for calculating the electromagnetic force distribution over the stator. Various sources of noise in induction motors and their behaviour with speed and load have been reviewed. Models of the electromagnetic field and vibro-acoustic character have been discussed. An outline of various techniques of reducing noise in induction motors through design of inverters and modifications to the motor structure has been given. Experiments were conducted to assess the effect of controller strategies on the radiated sound power. Three different supplies were tested: a dynamotor which produces an almost sinusoidal supply with very low harmonic content, an inverter with a low switching frequency (less than 1kHz) and an inverter with a high switching frequency (8kHz) and various levels of random modulation. Results indicate that the sound power level of the MSC drive is a lot higher than that of the VSC 2000 drive and the dynamotor drive. The sound power level of the VSC 2000 drive and the dynamotor drive increases almost linearly with motor speed, that for the MSC drive is almost independent of speed. The sound power level of the MSC drive is almost 28dB higher than that of the dynamotor drive at 450rpm and the difference is reduced to 14dB at 1500rpm where the aerodynamic noise becomes more dominant. It has been found that at the rated speed (1500rpm), the sound power level varies by less than 3dB from no load to full load for all three sources. Although increasing the switching frequency increases the cost of the inverters and switching losses, results from the MSC and VSC 2000 drives clearly show that it reduces the radiated sound power by shifting the harmonics into higher and inaudible frequency range. The tonal nature around the switching frequency has been reduced by increasing the levels of random modulation to spread the energy over a wider range of frequencies, although the sound power level has not varied by more than 0.2dB. A finite element model has been developed to calculate the electromagnetic force distribution. The quasi-static solution method has been implemented by stepping the rotor through the time domain using a fine regular mesh in the air gap. The stator currents were experimentally obtained while the rotor currents were obtained using a 4 parameter state space model of the motor. Results of the simulation indicate the influence of stator and rotor slots, saturation and time harmonics in the current. The calculated electromagnetic force distribution has been used in a FEM/BEM acoustic model and SEA acoustic model to predict the radiated sound power which agrees reasonably well with the measured sound, thus validating indirectly the electromagnetic force simulations.
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Nour, Fathy E. "The analysis of vibration signals during induction motor starting transients with a view to early fault detection." Thesis, Robert Gordon University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294706.
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Marques, Miguel Alexandre Castanheira. "On-line system for faults detection in induction motors based on PCA." Master's thesis, Faculdade de Ciências e Tecnologia, 2012. http://hdl.handle.net/10362/8578.
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Dissertation to obtain the degree of Master in Electrical and Computer EngineeringNowadays in the industry there many processes where human intervention is replaced by electrical machines, especially induction machines due to his robustness, performance and low cost. Although, induction machines are a high reliable device, they are also susceptible to faults. Therefore, the study of induction machine state is essential to reduce human and financial costs. The faults in induction machines can be divided mainly into two types: electrical faults and mechanical faults. Electrical faults represent between 40% and 50% of the reported faults and can be divided essentially in 2 types: stator unbalances and broken rotor bars. Taking into account the high dependency of induction machines and the massive use of automatic processes the industrial level, it is necessary to have diagnostic and monitoring systems these machines. It is presented in this work an on-line system for detection and diagnosis of electrical faults in induction motors based on computer-aided monitoring of the supply currents. The main objective is to detect and identify the presence of broken rotor bars and stator short-circuits in the induction motor. The presence of faults in the machine causes different disturbances in the supply currents. Through a stationary reference frame, such as αβ transform it is possible to extract and manipulate the results obtained from the supply currents using Eigen decomposition.
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Pina, Ortega Alejandro Jose. "Design and Comparison of Induction Motor and Synchronous Reluctance Motor for Variable Speed Applications: Design Aided by Differential Evolution and Finite Element Analysis." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1365429279.
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Štěpanovský, Libor. "Vyhodnocení provozního stavu asynchronních motorů jaderné elektrárny Dukovany metodou frekvenční analýzy statorového proudu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2021. http://www.nusl.cz/ntk/nusl-442548.
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The masters thesis is concerned with the setting of limits and criteria, the design of database environment and the evaluation of the current state of motors of the important machines related to own consumption of the Nuclear power plant Dukovany. The first part of the thesis is a short description of induction motors, the evaluation method and the inventory of the observed motors related to own consumption of Nuclear power plant Dukovany. The second part of the thesis concerns the design of limits and criteria for evaluating the current state of these important motors. Finally, the thesis shows a short description of the electro monitoring system together with the description of the database environment created. In the supplementary materials of the thesis, there is a design of a protocol template for evaluation of the current state of the motor and a technical report template for regular evaluation in monitored areas MCSA (Motor Current Signature Analysis) of the state of the induction motors.
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Wu, Long. "Separating Load Torque Oscillation and Rotor Faults in Stator Current Based-Induction Motor Condition Monitoring." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/14545.
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Stator current spectral analysis techniques are usually used to detect rotor faults in induction machines. Magnetic field anomalies in the airgap due to the rotor faults result in characteristic side-band harmonic components in the stator current spectrum, which can be measured as rotor fault signatures. A position-varying load torque oscillation at multiples of the rotational speed, however, has exactly the same effect. Stator current harmonics due to a load torque oscillation often obscure and even overwhelm rotor eccentricity fault detection since the magnitude of load oscillation induced harmonics is usually much larger.
Although previous research has suggested some methods to differentiate between these two effects, most of them rely heavily on the accurate estimation of motor parameters. The objective of this research is to develop a far more practical and computationally efficient method to detect rotor faults effectively in the presence of a load torque oscillation. A significant advantage of the proposed scheme is that it does not need any knowledge of motor parameters. The normalized negative sequence information induced by a mixed rotor eccentricity in the stator current or terminal voltage space vector spectra, serves as a reliable rotor fault indicator to eliminate load oscillation effects.
Detailed airgap magnetic field analysis for an eccentric motor is performed and all machine inductance matrices as well as their derivatives are reformulated accordingly. Careful observation of these inductance matrices provides a fundamental understanding of motor operation characteristics under a fault condition. Simulation results based on both induction motor dynamic model and Maxwell 2D Finite Element Model demonstrate clearly the existence of the predicted rotor fault indicator. Extensive experimental results also validate the effectiveness and feasibility of the proposed detection scheme.
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Narayanan, G. "Synchronised Pulsewidth Modulation Strategies Based On Space Vector Approach For Induction Motor Drives." Thesis, Indian Institute of Science, 1999. http://hdl.handle.net/2005/139.
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In high power induction motor drives, the switching frequency of the inverter is quite low due to the high losses in the power devices. Real-time PWM strategies, which result in reduced harmonic distortion under low switching frequencies and have maximum possible DC bus utilisation, are developed for such drives in the present work.
The space vector approach is taken up for the generation of synchronised PWM waveforms with 3-Phase Symmetry, Half Wave Symmetry and Quarter Wave Symmetry, required for high-power drives. Rules for synchronisation and the waveform symmetries are brought out. These rules are applied to the conventional and modified forms of space vector modulation, leading to the synchronised conventional space vector strategy and the Basic Bus Clamping Strategy-I, respectively. Further, four new synchronised, bus-clamping PWM strategies, namely Asymmetric Zero-Changing Strategy, Boundary Sampling Strategy-I, Basic Bus Clamping Strategy-II and Boundary Sampling Strategy-II, are proposed. These strategies exploit the flexibilities offered by the space vector approach like double-switching of a phase within a subcycle, clamping of two phases within a subcycle etc. It is shown that the PWM waveforms generated by these strategies cannot be generated by comparing suitable 3-phase modulating waves with a triangular carrier wave.
A modified two-zone approach to overmodulation is proposed. This is applied to the six synchronised PWM strategies, dealt with in the present work, to extend the operation of these strategies upto the six-step mode. Linearity is ensured between the magnitude of the reference and the fundamental voltage generated in the whole range of modulation upto the six-step mode. This is verified experimentally.
A suitable combination of these strategies leads to a significant reduction in the harmonic distortion of the drive at medium and high speed ranges over the conventional space vector strategy. This reduction in harmonic distortion is demonstrated, theoretically as well as experimentally, on a constant V/F drive of base frequency 50Hz for three values of maximum switching frequency of the inverter, namely 450Hz, 350Hz and 250Hz.
Based on the notion of stator flux ripple, analytical closed-form expressions are derived for the harmonic distortion due to the different PWM strategies. The values of harmonic distortion, computed based on these analytical expressions, compare well with those calculated based on Fourier analysis and those measured experimentally.
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Gule, Nkosinathi. "Analysis and evaluation of brush-DC equivalent controlled multiphase cage induction machine drive." Thesis, Stellenbosch : University of Stellenbosch, 2011. http://hdl.handle.net/10019.1/6489.
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Thesis (PhD (Electrical and Electronic Engineering))--University of Stellenbosch, 2011.ENGLISH ABSTRACT: The multiphase induction machine drive has been under investigation for the last half century. Although it offers several attractive advantages over the conventional three-phase induction machine drive, it is restricted to highly specialised applications. One aspect of the multiphase induction machine drive is the complexity of the control algorithm for decoupled flux and torque control. The complexity, arising from the required coordinate transformations, increases with increase in the number of phases of the machine. Recently, a method that allows the control of a six-phase induction machine drive without any coordinate transformations was developed and tested. This new control technique allows the control of the machine to be similar to that of dc machines through the use of special trapezoidal-shaped stator current waveforms. These stator phase current waveforms consist of field (flux) and torque current components, with flat-topped amplitudes allowing a stator phase to act alternately in time as either a flux or a torque producing phase. The idea is to have a number of stator phases acting as flux producing phases, whilst the remaining phases act as torque producing phases at each time instance. This dissertation takes a further step in the research on this particular control technique. As the control method relates directly to the brush-dc machine operation, in this dissertation, the control method is defined as a “brush-dc equivalent” (BDCE) control method. First, in this dissertation, a simple analytical method is developed to determine a defined optimal ratio of the number of field to the number of torque phases of a multiphase induction machine that utilises trapezoidal stator current waveforms. The method is applied to induction machines with up to fifteen stator phases. Finite element analysis is used to verify the validity of the developed criterion and to verify the square-like air gap flux density. Secondly, in this dissertation, an analytical method for predicting and evaluating the rotor bar current waveform of a cage multiphase induction machine is proposed. The method is based on the Fourier transform and the winding function theory under linear condition assumptions. The method also allows for the calculation of the electromagnetic torque and rotor bar losses. Skin effect is considered in the calculation of the rotor bar resistance of the machine. Again, finite element analysis is used to verify the analytically calculated results. The developed method can be expanded and used to evaluate the rotor current waveform of any multiphase induction machine supplied with any stator current waveforms. The BDCE control method is implemented on a prototype nine-phase cage-rotor induction machine drive. A nine-phase inverter and control system are developed for supplying the nine-phase induction machine with the trapezoidal stator current waveforms. Rotor current waveform measurements are taken on a specially designed rotor to verify the analytically predicted waveform. The linear relationship of the developed torque and torque current of the proposed BDCE control method is verified through measurements. Through the comparison of analytical calculated results with finite element calculated and measured results, it is shown in this dissertation that the developed analytical techniques can be used in the design and performance analysis of multiphase induction machines. Also, from the results, it is clear that the new control technique works remarkably well even in the flux weakening region. However, outstanding aspects, such as efficiency and generated torque quality of the proposed drive still need to be investigated further.
AFRIKAANSE OPSOMMING: Die multifase induksiemasjien aandryfstelsel word in die laaste halwe eeu al in navorsing ondersoek. Alhoewel dit verskeie aantreklike voordele bied bo die konvensionele driefase induksiemasjien aandryfstelsel, is dit beperk tot hoogs gespesialiseerde aanwendings. Een aspek van die multifase induksiemasjien aandryfstelsel is die kompleksiteit van die beheer algoritme vir ontkoppelde vloed en draaimoment beheer. Die kompleksiteit, wat voortspruit uit die vereiste koördinaat transformasies, neem toe met toename in die aantal fases van die masjien. Onlangs is 'n metode wat die beheer van ’n sesfase induksiemasjien sonder enige koördinaat transformasies doen, ontwikkel en getoets. Hierdie nuwe beheertegniek maak die beheer van die masjien soortgelyk aan dié van GS masjiene deur die gebruik van spesiale trapezium-vormige statorstroom golfvorms. Hierdie stator fasestroom golfvorms bestaan uit veld- (vloed-) en draaimoment-stroom komponente met plat amplitudes, sodat 'n statorfase om die beurt in tyd optree as óf' ’n vloed of 'n draaimoment genereerde fase. Die idee is om 'n aantal statorfases te hê wat as vloed genereerde fases dien, terwyl die oorblywende fases as draaimoment genereerde fases optree op enige tydstip. Hierdie tesis neem 'n verdere stap in die navorsing op hierdie spesifieke beheertegniek. Met die beheermetode wat direk verband hou met borsel-GS masjien werking, word in hierdie proefskrif die beheermetode as 'n "borsel-GS ekwivalente" ["brush-DC equivalent" (BDCE)] beheermetode gedefinieer. In die eerste plek word in hierdie proefskrif 'n eenvoudige analitiese metode ontwikkel om ’n gedefinieerde optimale verhouding van die aantal veld tot die aantal draaimoment fases van 'n multifase induksiemasjien te bepaal, wat van trapesoïdale statorstroom golfvorms gebruik maak. Die metode word toegepas op induksiemasjiene met tot vyftien statorfases. Eindige element analise is gebruik om die geldigheid van die ontwikkelde kriterium te verifieer en om die vierkantvormige luggaping vloeddigtheid te verifieer. In die tweede plek word in hierdie proefskrif 'n analitiese metode vir die voorspelling en evaluering van die rotorstaafstroom golfvorm van 'n kourotor multifase induksiemasjien voorgestel. Die metode is gebaseer op die Fourier transform en die wikkelingsfunksie teorie onder lineêre-toestand aannames. Die metode wend hom ook daartoe tot die berekening van die elektromagnetiese draaimoment en rotorstaafverliese. Die huideffek word in ag geneem in die berekening van die rotorstaafweerstand van die masjien. Weereens is eindige element analise gebruik om die analitiese berekende resultate te verifieer. Die ontwikkelde metode kan uitgebrei en gebruik word om die rotorstroom golfvorm van van enige multifase induksiemasjien te evalueer wat gevoer word met enige statorstroom golfvorms. Die BDCE beheermetode is toegepas op 'n prototipe negefase kourotor induksiemasjien. 'n Negefase omsetter en beheerstelsel is ontwikkel vir die toevoer van die trapesoïdale statorstroom golfvorms aan die negefase induksiemasjien. Die rotorstroomgolfvorm metings is geneem op 'n spesiaal ontwerpte rotor om die analitiese voorspelde golfvorm te verifieer. Die lineêre verwantskap tussen die ontwikkelde draaimoment en draaimomentstroom van die voorgestelde BDCE beheermetode is geverifieer deur metings. Deur die analitiese berekende resultate met die eindige element berekende en gemete resultate te vergelyk, wys hierdie proefskrif dat die ontwikkelde analitiese tegnieke gebruik kan word in die ontwerp en werkverrigting analise van ’n multifase induksiemasjien. Vanuit die resultate is dit ook duidelik dat die nuwe beheertegniek besonder goed werk, selfs in die vloedverswakking spoedgebied. Egter, uitstaande aspekte soos effektiwiteit en genereerde draaimoment kwaliteit van die voorgestelde aandryfstelsel moet nog verder ondersoek word.
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Deshmukh, Ram Raghotham Rao. "Voltage harmonics analysis and efficiency of three-phase induction motor with change in coil pitch of the stator winding." Thesis, Cardiff University, 2006. http://orca.cf.ac.uk/56143/.
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Variable speed drives employing induction motors have been widely used in industry for decades. Today there is a continually increasing demand for more precise and flexible speed control usually with close attention to energy efficiency. The inverter is used because of its reliability, flexibility and relatively low cost. However its output a.c. voltage is not sinusoidal so the core losses in the induction motors consequently increase. This research is centred on the design and testing of the stator winding configuration of three phase induction motors with various coil pitches and measure the dynamic performance under sinusoidal and PWM supplies. Measurements were carried out to determine the behavior of harmonic losses and the efficiency of four identical three-phase 746 W induction motors with stator coil pitches of 180 , 160 , 140 and 120 . The motors were fed from either a three-phase inverter or a three-phase sinusoidal voltage supply. The switching frequency was varied from 4 kHz to 16 kHz and the modulation frequency was varied between 30 Hz to 60 Hz. Simulations were carried out using OPERA 2D software under sinusoidal voltage supply. The phenomenon of chording by l/n* of pole pitch to suppress the n* harmonic was particularly followed by motors with 120 and 160 coil pitches under sinusoidal voltage supply. This phenomenon was also followed by 120 , 140 and 160 coil pitch motors under PWM voltage supply at all the switching frequencies and modulation * frequencies. The motor with 120 coil pitch showed a drastical increase in the lower order voltage harmonic components with simulation under sinusoidal supply when compared to full pitch motor. The total voltage harmonic distortion due to the third, fifth and ninth harmonics was less for the motor with 120 coil pitch under PWM voltage at higher switching frequencies and under over modulation condition. The efficiency of the same motor was higher at full load and over loads under all the switching frequencies and modulation frequencies. The measurement results and discussion enable motor manufacturers to consider 120 coil pitch motor under PWM voltage supply and 160 coil pitch motor under sinusoidal voltage supply for the 746 W induction motors as the increase in the efficiencies were 12% and 5% respectively when compared to full pitch motor.
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Volf, Lukáš. "Výpočet jednofázového asynchronního motoru." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219750.
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This work is in the first chapter deals with the basic properties of single phase and three-phase induction motors. The following describes the procedure for obtaining a starting torque of single-phase asynchronous motor. In the second part of the calculation is carried out single-phase induction motor with a permanently connected capacitor and its control, calculation of output values, the program proposed solution to this calculation in Microsoft Excel 2007 and calculated parameters of the development of methods of calculation were compared with measured, the values supplied by ATAS Náchod.
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Guimaraes, Geraldo C. "Computer methods for transient stability analysis of isolated power generation systems with special reference to prime mover and induction motor modelling." Thesis, University of Aberdeen, 1990. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU028173.
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This thesis aims to establish computer methods for the transient stability analysis of electric power systems which operate isolated from the large interconnected system. A typical isolated system is characterized by a compact network in which the size of the load is relatively large when compared to the total, installed generation capacity. The stability problems are thus more severe for this system than for the grid-type system. This results in the need for more accurate representations for the system components in the computer studies. This work considers particularly the prime mover and the induction motor modelling. The accurate modelling for turbo-charged diesel engines and single shaft gas turbines is considered first due to the significative presence of these types of prime movers in the isolated systems. The quasi-steady approach is adopted in the development of these models. The induction motor modelling is then dealt with and an accurate model which accounts for the deep-bar effects and includes the stator transients is presented. In addition, this work also investigates the possibility of substituting all these detailed models by simple, reduced models in the computer simulations since the latter pose less problem in assembling the necessary data than the former ones. Furthermore, some theoretical aspects for the representation of synchronous machines, automatic voltage regulators and transformers are included in the thesis. Some insight on the numerical integration method used in the stability program - the Trapezoidal implicit - is also given in the text with the advantages and disadvantages being stated. Several studies are shown in the thesis which aim firstly to compare the various models for prime mover and induction motor representations and secondly to test the complete simulation package when dealing with stability analyses of typical isolated systems.
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Blödt, Martin. "Condition Monitoring of Mechanical Faults in Variable Speed Induction Motor Drives. Application of Stator Current Time-Frequency Analysis and Parameter Estimation." Phd thesis, Toulouse, INPT, 2006. http://oatao.univ-toulouse.fr/7468/1/blodt.pdf.
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This Ph.D. thesis deals with condition monitoring of mechanical failures in variable speed induction motor drives by stator current analysis. Two effects of a mechanical fault are considered: load torque oscillations and airgap eccentricity. The analytical modelling using the magnetomotive force and permeance wave approach leads to two stator current models. The fault provokes amplitude or phase modulation of the fundamental current component. Suitable detection methods are spectral analysis and parameter estimation in steady state whereas time-frequency analysis is required during transients. Instantaneous frequency estimation, the Wigner Distribution and the spectrogram are studied. Simulation and experimental results validate the theoretical approach. Automatic extraction of fault indicators is proposed for an unsupervised monitoring system. Moreover, load torque oscillations and dynamic eccentricity can be discriminated with the proposed methods. The feasibility of an on-line monitoring system is demonstrated by a DSP implementation of the time-frequency analysis including indicator extraction.
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Pothuraju, Maneesha. "A Study on the Electromagnetic and Mechanical Vibrations of a Dynamometer Using Spectral Analysis." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1613747909641685.
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Juchelka, Roman. "Návrh asynchronního motoru pro kaskádní systém čerpání kapalin." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2016. http://www.nusl.cz/ntk/nusl-241987.
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This thesis deals with the design of electrical machine for direct drive of cascade liquid pumping system. At the beginning a suitable type of electrical machine and some of its basic parameters are selected. Finally, the 4 pole three phase induction machine powered by alternating voltage 3x400 V was chosen. After that complete design is made with respect to all specified requirements. The designed machine is analyzed with the use of ANSYS Maxwell and RMxprt software. The main outcome of the thesis are dimensional sketches of the engine that will be used as the basis for the production of the prototype.
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Cruz, Amanda Guerra de Araújo. "Sistema híbrido para diagnóstico de falhas em motores de indução trifásicos com base no método vibracional, corrente de armadura e lógica fuzzy." Universidade Federal da Paraíba, 2015. http://tede.biblioteca.ufpb.br:8080/handle/tede/8962.
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The three-phase induction motors are the most important way for electromechanical conversion, being present in almost every industrial process. Because of their importance, it is crucial that these devices have a proper predictive maintenance, avoiding lost production and operational accidents in the event of unexpected failures. In this scenario several researchers have conducted studies to detect incipient faults. About the sensing method used, the most common techniques are related to measuring the vibration levels using accelerometers and measuring electrical motor signals. The choice of technique involves factors such as invasiveness, drive motor type and the sensitivity to failure. The purpose of this work involves the development of a hybrid system that uses data collected by vibration and current sensors for fault detection in induction motors, earlier and more efficiently. The current and vibration signals were processed in the frequency domain and through the multiresolution analysis, serving as inputs of a fuzzy logic system, allowing to increase the sensitivity and efficiency in fault detection techniques in relation to the individual. The unbalance failure was investigated on a workbench with the motor coupled to a propeller and broken bars with another bench with DC motor to apply the load, the best methods being chosen in each case. The system was developed in Matlab software and was validated with correct detection for both failures, being able to detect the unbalance failure on the shaft or propeller as broken bars in different load conditions.
O motor de indução trifásico é o principal meio de conversão eletromecânica existente, estando presente em praticamente todos os processos industriais. Devido à sua importância, é fundamental que estes equipamentos tenham uma correta manutenção preditiva, evitando perda de produção e acidentes operacionais em caso de falhas inesperadas. Diante deste cenário vários pesquisadores têm realizado estudos para detecção de falhas incipientes. Quanto ao método sensor utilizado, as técnicas mais comuns estão relacionadas a medição dos níveis de vibração utilizando acelerômetros e medição de sinais elétricos do motor. A escolha da técnica envolve fatores como a invasividade, tipo de acionamento do motor e a sensibilidade à falha. A proposta deste trabalho envolve o desenvolvimento de um sistema híbrido que utilize dados coletados por sensores de vibração e de corrente para detecção de falhas incipientes em motores de indução trifásicos de maneira mais precoce e eficiente. Os sinais de corrente e de vibração foram processados no domínio da frequência pela transformada de Fourier e através da análise multiresolução, servindo como entrada para sistemas de lógica Fuzzy, permitindo que se aumente a eficiência na detecção da falha em relação às técnicas individuais. Foi investigada a falha de desbalanceamento em uma bancada com o motor acoplado a uma hélice e barras quebradas em outra bancada com motor de corrente contínua acoplado para aplicar a carga, sendo escolhidos os melhores métodos em cada caso. O sistema foi desenvolvido no software Matlab e foi validado através de diagnósticos corretos para ambas as falhas, sendo capaz de detectar a falha de desbalanceamento tanto na hélice quanto no eixo e de barras quebradas em diferentes condições de carga.
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Karásek, Ladislav. "Návrh vysokootáčkového motoru 350kW 40 000min-1." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2016. http://www.nusl.cz/ntk/nusl-242110.
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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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Nóbrega, Sobrinho Carlos Alberto. "Estudo comparativo de técnicas para Diagnóstico de falhas em motores de Indução trifásicos." Universidade Federal da Paraíba, 2015. http://tede.biblioteca.ufpb.br:8080/handle/tede/8958.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Electrical motors are responsible for 95% of primary movement source in industrialized nations. Among those, 90% are Three-Phase Induction Motors, present in almost all industrial sectors. Due to its importance on this sector, there is a need for monitoring them in order to avoid production stops and operational disasters. In this work, studies were conducted on common fault diagnostics in Three-Phase Induction Motors intending industrial applications. Different sensoring techniques were used and their performance were analyzed. An embedded system was developed to make field applications with different techniques possible. This installation can be done noninvasively and data collection can be obtained in real time. Fast Fourier Transform (FFT) and wavelet processing techniques are used as tools in mathematical processing of the data. In the first moment, fault analyses were conducted offline making use of data acquisition devices and further processing of the information. In a second phase, the embedded system was used to monitor automatically (online) the evolution of the damage developed. The system receives the motor current signal, and using local processing, conducts the spectral analysis of the signal identifying incipient faults. These data are available for communication with or without wires. For the embedded system implementation, the algorithms were adjusted to comply with the embedded hardware resources restrictions. Through theoretical and experimental development, several techniques were used and compared with the objective of performing a full diagnostic TIM malfunction. The experimental results corroborate the theoretical ones, and it was conducted a detailed study of the methods on the state of the art and new approaches were made.
industrializadas. Desses, 90% são motores de indução trifásicos (MIT), estando presentes em praticamente todos os setores industriais. Devido a sua importância no setor produtivo, existe a necessidade que os mesmos sejam devidamente monitorados evitando interrupções na produção e desastres operacionais. Nesse trabalho foram realizados estudos para diagnósticos de falhas comuns em motores de indução trifásicos visando aplicação industrial. As diferentes técnicas de sensoriamento foram utilizadas e o desempenho de cada método foi analisado. Um sistema embarcado foi desenvolvido com o intuito de se viabilizar as aplicações em campo, cuja instalação pode ser realizada de forma não invasiva e as informações podem ser obtidas em tempo real. A Transformadas Rápida de Fourier (FFT) e as técnicas de processamento wavelet serão utilizadas como ferramentas matemáticas no tratamento dos dados. Em um primeiro momento, as análises das falhas foram feitas de forma off-line, fazendo uso de placas de aquisição de dados e um posterior tratamento das informações. Em um segundo momento, foi desenvolvido o sistema embarcado que faz um monitoramento automático (online) da evolução da avaria, que recebe o sinal de corrente do motor e, utilizando processamento local, faz a análise espectral do sinal identificando falhas incipientes. Esses dados ficam disponíveis (off line e on line) por comunicação com ou sem fios. Para a implementação do sistema embarcado, os algoritmos foram ajustados de modo a respeitar as restrições de recursos do hardware embarcado. Através de desenvolvimento teórico e experimental, várias técnicas foram utilizadas e comparadas com o objetivo de se realizar um diagnóstico completo de avaria de MIT. Os resultados experimentais corroboram com os teóricos e foi realizado um estudo aprofundado dos métodos do estado da arte e novas abordagens foram realizadas.
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Kostov, Jiří. "Výpočet jednofázového asynchronního motoru." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2013. http://www.nusl.cz/ntk/nusl-219928.
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Diploma Thespis is focused on development, parameters and construction of one-phase induction motor underplayed by calculations. Emphasis was dealt to simplify motor development process by developed computer program. Program calculations were approved by parallel by hand calculations and by experimental measuring of real processed motor.
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Dejan, Reljić. "Otkrivanje kvara rotora kaveznog asinhronog motora primenom tehnika analize terminalnih veličina." Phd thesis, Univerzitet u Novom Sadu, Fakultet tehničkih nauka u Novom Sadu, 2017. https://www.cris.uns.ac.rs/record.jsf?recordId=104840&source=NDLTD&language=en.
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U disertaciji je predložena metoda za pouzdano otkrivanje kvara rotoratrofaznog kaveznog asinhronog motora. Metoda je zasnovana naidentifikaciji obeležja kvara rotora iz signala terminalnih veličinajednofazno napojenog trofaznog kaveznog motora u stacionarnom stanjupogona. Predložena metoda eliminiše potrebu za postojanja opterećenjamotora, što je osnovna prednost u odnosu na rešenja iz literature. Svateorijska razmatranja su praćena odgovarajućim rezultatima računarskihsimulacija, da bi se potom sprovela eksperimentalna verifikacija ipotvrdila efikasnost predložene metode. Takođe, predstavljen jepostupak za kvantitativnu procenu oštećenja štapnih provodnika rotora.In this Doctoral dissertation, a novel method for broken rotor bar fault detectionin a three-phase squirrel-cage induction motor (IM) is introduced. The proposedmethod is non-invasive and it is based on the analysis of the IM terminalquantities in a single-phase steady-state operating condition. Compared toconventional fault detection techniques, the developed method does not requireany loading on the motor, which is the main benefit of the method. The faultycondition of broken rotor bars was investigated analytically, while theeffectiveness of the proposed method was proven by the variety of computersimulations and experimental results. Based on these results, a methodology forthe quantification of broken rotor bars in the IM has been presented.
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Lyra, Gabriela Jordão. "Análise de métodos para estimação da velocidade no eixo de motores de indução trifásicos." Universidade Federal da Paraíba, 2014. http://tede.biblioteca.ufpb.br:8080/handle/tede/5386.
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Previous issue date: 2014-10-04Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
The three phase induction motor (MIT) is the main system in electromechanical conversion, present in practically all industrial processes. Due to its versatility and low cost, the use of frequency inverters combined with MIT practically replaced the DC motors in systems requiring variation in angular velocity. For closed-loop control at MIT, without the use of speed sensors (sensorless), it is essential to estimate the velocity on the axis with high accuracy and with satisfactory response time. The proposed work has the object of analyzing different methods that can be employed to estimate the speed in sensorless axis, named according to their fundamental principle, they are: the method of harmonic slots, the torque in the air gap and the acoustic emission. The first mentioned is the best known non-invasive method in the state art, the second one was recently developed in the laboratory and the third one was exhibited here for the first time. All methods are compared with a reference instrument for measuring speed (tachometer). In order to obtain validation of the techniques we constructed a work bench tests basically composed by a three phase induction motor, torque meter and DC motor used as a generator (to enforce the axis load variable). The main objective of the study is to compare the methods for various situations of speed and load, also based on the degree of invasiveness and accuracy of each method. For the development and analysis of technique for harmonic slots and acoustic emission, a spectral analysis by Fourier transform of the current signal and the sound was performed, respectively. It was used tools such as MATLAB and LABVIEW for the computational study. After extensive experimental testing, the methods have been validated and it was obtained conclusions about different aspects of each discussed technique.
O motor de indução trifásico (MIT) é o principal sistema de conversão eletromecânica existente, presente em praticamente todos os processos industriais. Devido a sua versatilidade e razoável baixo custo, a utilização de inversores de frequência combinados com os MIT, praticamente, substituíram os motores de corrente contínua em sistemas que necessitam de variação de velocidade angular. Para o controle de malha fechada em MIT, sem a utilização de sensores de velocidade (sensorless), é fundamental que se estime a velocidade no eixo com alta exatidão e com tempo de resposta satisfatório. O trabalho proposto visa analisar diferentes métodos que podem ser empregados para estimação na velocidade no eixo sensorless, denominados de acordo com o seu princípio fundamental, são eles: método pela harmônicas das ranhuras, pelo torque no entreferro e pela emissão acústica. Sendo o primeiro citado, o método não-invasivo mais conhecido no estado arte, o segundo, desenvolvido recentemente em laboratório e o terceiro, exposto aqui pela primeira vez. Todos os métodos são comparados com um instrumento de referência para medida de velocidade (tacômetro). A fim de se obter a validação das técnicas empregadas foi construída uma bancada de testes experimentais composta basicamente por um motor de indução trifásico, torquímetro e motor de corrente contínua utilizado como gerador (para impor carga variável ao eixo). O principal objetivo do estudo é comparar os métodos para diversas situações de velocidade e carga, tendo também como base o grau de invasividade e exatidão de cada método. Para o desenvolvimento e análise da técnica pela harmônicas das ranhuras e da emissão acústica, foi realizada uma análise espectral pela Transformada de Fourier do sinal da corrente e do som, respectivamente. Usou-se para este estudo ferramentas computacionais como o LABVIEW e MATLAB. Depois de extensos ensaios experimentais, os métodos foram validados e obteve-se conclusões sobre diferentes aspectos de cada técnica analisada.
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Dias, Cleber Gustavo. "Proposta de um novo método para a detecção de barras rompidas em motores de indução com rotor em gaiola." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/3/3143/tde-15092006-165225/.
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O estudo das condições de operação de um motor de indução em um ambiente industrial é indispensável, tendo em vista que eventuais problemas podem contribuir para um prejuízo na produção, ou ainda para custos adicionais relacionados à falta de manutenção dos equipamentos. Uma das principais falhas que podem ocorrer em um motor de indução do tipo gaiola de esquilo durante sua operação é o rompimento de uma ou mais barras que compõem o seu rotor. Apresenta-se neste trabalho um novo método para auxiliar na detecção de barras quebradas em um rotor tipo gaiola de esquilo, para um motor de grande porte, durante sua operação em regime permanente. A partir de um modelo matemático foi possível avaliar o rompimento de barras do rotor, detectando em uma posição específica, a variação da densidade de fluxo magnético resultante, produzida pela contribuição do fluxo de dispersão de cada barra do rotor, bem como pelo fluxo criado pelas correntes do estator. Um sensor de efeito Hall é instalado entre duas bobinas do estator, a fim de representar a posição onde é realizado o cálculo da densidade de fluxo magnético resultante pela modelagem matemática proposta. O sinal gerado pelo sensor a partir de uma falha é comparado com aquele obtido a partir do rotor saudável, para posterior análise. O trabalho sugere ainda a aplicação do método de detecção da falha em conjunto com uma técnica de inteligência artificial baseada nas redes neurais artificiais, a fim de contribuir para o diagnóstico da falha e estimativa do número de barras rompidas. Os resultados obtidos da simulação, bem como os dados obtidos durante o ensaio são apresentados e usados na validação do modelo matemático desenvolvido.The study of operational conditions of an induction motor in an industrial environment is indispensable, once eventual problems can contribute for production losses, or still for additional costs related to the lack of equipments maintenance. Among the principal faults, in a squirrel cage induction motor can occur the breaking of one or more rotor bars. This work presents a new method in aid of detection of broken bars in a large squirrel cage induction motor during its operation in steady-state. A mathematical model is used to evaluate the broken rotor bars, detecting in a specific point, the resulting magnetic flux density produced by the leakage flux created by the rotor and stator currents. The Hall effect sensor is installed between two stator coils, in order to represent the position where the resulting magnetic flux density is calculated by the proposed mathematical model. The signal detected in the sensor during a fault, is compared to the obtained result of the magnetic flux density from a healthy rotor for analysis. The work still suggests the application of the artificial intelligence technique, based on artificial neural networks in the mathematical model, in order to aid on the fault detection and estimate of the number of broken bars. The simulation and experimental results are presented in order to validate the developed mathematical model.
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Chvatík, Štěpán. "Asynchronní motor s vnějším rotorem." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2018. http://www.nusl.cz/ntk/nusl-377075.
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Lu, Bin. "Energy Usage Evaluation and Condition Monitoring for Electric Machines using Wireless Sensor Networks." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/14152.
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Energy usage evaluation and condition monitoring for electric machines are important in industry for overall energy savings. Traditionally these functions are realized only for large motors in wired systems formed by communication cables and various types of sensors. The unique characteristics of the wireless sensor networks (WSN) make them the ideal wireless structure for low-cost energy management in industrial plants.
This work focuses on developing nonintrusive motor-efficiency-estimation methods, which are essential in the wireless motor-energy-management systems in a WSN architecture that is capable of improving overall energy savings in U.S. industry.
This work starts with an investigation of existing motor-efficiency-evaluation methods. Based on the findings, a general approach of developing nonintrusive efficiency-estimation methods is proposed, incorporating sensorless rotor-speed detection, stator-resistance estimation, and loss estimation techniques. Following this approach, two new methods are proposed for estimating the efficiencies of in-service induction motors, using air-gap torque estimation and a modified induction motor equivalent circuit, respectively. The experimental results show that both methods achieve accurate efficiency estimates within ¡À2-3% errors under normal load conditions, using only a few cycles of input voltages and currents. The analytical results obtained from error analysis agree well with the experimental results.
Using the proposed efficiency-estimation methods, a closed-loop motor-energy-management scheme for industrial plants with a WSN architecture is proposed. Besides the energy-usage-evaluation algorithms, this scheme also incorporates various sensorless current-based motor-condition-monitoring algorithms. A uniform data interface is defined to seamlessly integrate these energy-evaluation and condition-monitoring algorithms. Prototype wireless sensor devices are designed and implemented to satisfy the specific needs of motor energy management. A WSN test bed is implemented. The applicability of the proposed scheme is validated from the experimental results using multiple motors with different physical configurations under various load conditions. To demonstrate the validity of the measured and estimated motor efficiencies in the experiments presented in this work, an in-depth error analysis on motor efficiency measurement and estimation is conducted, using maximum error estimation, worst-case error estimation, and realistic error estimation techniques. The conclusions, contributions, and recommendations are summarized at the end.
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Buchta, Luděk. "Kompenzace nelinearit při řízení střídavých pohonů." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2019. http://www.nusl.cz/ntk/nusl-408028.
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Analysis of the dead-time effect and other nonlinearities of the voltage source inverter was carried out in the introduction of the doctoral thesis. Three compensation strategies for vector controlled PMSM were proposed based on the analysis. The voltage disturbance observer with cost function of current errors is based on the model of PMSM, known machine parameters and easily measurable quantities. The second observer which estimates the dq- axes currents and the value of the voltage error with one parameter only is designed based on the harmonic analysis and Kalman filter algorithm. The third method combines an adaptive approach with feedback and voltage disturbance observer that is based on the PMSM model. Furthermore, the two compensation methods for vector controlled induction motor were proposed. In the first case, the standard compensation strategy is extended by a harmonic compensator that suppresses the residual 6th harmonic component in dq- axes currents. The last strategy detects the polarity of the estimated phase currents that are obtained by the Kalman filter. All compensation strategies have been verified by MATLAB/Simulink simulations and by experiments on real drives.
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Begg, Michael Colin. "Finite element analysis of induction motors." Thesis, Imperial College London, 1986. http://hdl.handle.net/10044/1/37942.
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Svoreň, Jan. "Návrh vysokootáčkového asynchronního motoru." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219753.
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This work deal with troubleshooting of problem parts of high-speed induction machines. Introduction is about conception of induction machines with reference to construction specialities due to high rpm and because machines are fed by inverter. Next part is focused to design problems. A classical induction machine was measured to determination change of various losses in classic and high-speed induction machines. The computation of laboratory sample high-speed motor was specified for calculation of effective resistance and leakage reactance of solid-steel rotor with copper layer. The results of numerical calculation were validated by using finite elements method and machine design was adjusted for improving operation characteristic.
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Stavrou, Andreas. "Analysis and simulation of faults in squirrel cage motors." Thesis, University of Aberdeen, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390266.
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Condition based maintenance of electrical machines offers significant advantages for industry. A large part of the research effort in this area is directed towards the evaluation of fault conditions. This thesis is concerned with analysing and modelling faults in induction motors. A method for evaluating the performance of induction machines with static and dynamic eccentricity is developed, using harmonic analysis of the air gap permeance. Models able to simulate eccentricity are presented. The slip ring model equations are obtained and then used to obtain the commutator models transformed to a single reference frame. A variety of effects accompanying these fault conditions are analysed, for example variation of the eccentricity level due to unbalanced magnetic pull and the possibilities of additional vibration harmonics examined. Damping of eccentricity fields due to current redistribution, saturation and slotting are discussed. Some general steady state calculations are also presented which show that the performance of the machine need not be changed over the operating range, due to such a fault. The characteristics of combined static and dynamic eccentricity are examined and it is shown that the combined asymmetry generates additional harmonic components which are not related to those which occur when the two asymmetries take place in isolation. The development of a simulation model of machines with broken rotor bars, based on the variation in rotor parameters is presented. Experimental investigations focus mainly on observable differences in the torque transient characteristics, due to such a condition. The possibilities for using current monitoring to identify inter-turn short circuits are investigated.
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LI, XIANG, and 李象. "Inverter-induction motor performance analysis." Thesis, 1989. http://ndltd.ncl.edu.tw/handle/60583838454078409230.
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LEE, HAN-CHUNG, and 李漢崇. "Application and Analysis of Induction Motor Protector." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/75423277148530322535.
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碩士崑山科技大學
機械工程研究所
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When the motor coil winding overheating or insulation properties decreased, the current flowing through the winding will cause a temperature rise, resulting in overheating of the motor coil winding. At this time, the motor needs a motor protection device. Usually the protection device of induction motor mainly has two kinds of current and temperature detection. This study analyzes the advantages and disadvantages of the existing motor protector. And then with the author of the service company designed a new type of protector to do the difference analysis among these protectors. Based on the difference analysis, the author uses the corporate resources to further develop new motor protector. The currently available motor does not require the installation of a motor protector. It is hoped that the development results of this new protector will be widely installed on newly manufactured motors to enhance the safety of motor use.