Academic literature on the topic 'Rotor ends'
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Journal articles on the topic "Rotor ends"
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Daif, Omar S., M. Helmy Abd El-Raouf, Mohamed Adel Esmaeel, and Abd Elsamie B. Kotb. "Economic design of sleeve rotor induction motor using rotor ends." International Journal of Electrical and Computer Engineering (IJECE) 12, no. 2 (2022): 1233. http://dx.doi.org/10.11591/ijece.v12i2.pp1233-1242.
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<span>In this paper, the field analysis of the sleeve rotor induction motor (IM) is carried out taking the rotor ends into consideration. Here, the field system equations are derived using the cylindrical model with applying Maxwell's field equations. It is expected that, both starting and maximum torques will increase with taking the rotor ends than that without rotor ends. A simple model is used to establish the geometry of the rotor ends current density and to investigate the air gap flux density. The magnetic flux is assumed to remain radially constant through the very small air gap length between the sleeve and stator surfaces. Variation of the field in the radial direction is ignored and the skin effect in the axial direction is considered. The axial distributions of the air gap flux density, the sleeve current density components and the force density have been determined. The motor performance is carried out taking into account the effects of the rotor ends on the starting and normal operations. The sleeve rotor resistance and leakage reactance have been obtained in terms of the cylindrical geometry of the machine. These equivalent circuit parameters have been calculated and plotted as functions of the motor speed with and without the rotor ends.</span>
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Omar, S. Daif, Helmy Abd Raouf M., Adel Esmaeel Mohamed, and Elsamie B. Kotb Abd. "Economic design of sleeve rotor induction motor using rotor ends." International Journal of Electrical and Computer Engineering (IJECE) 12, no. 2 (2022): 1233–42. https://doi.org/10.11591/ijece.v12i2.pp1233-1242.
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In this paper, the field analysis of the sleeve rotor induction motor (IM) is carried out taking the rotor ends into consideration. Here, the field system equations are derived using the cylindrical model with applying Maxwell's field equations. It is expected that, both starting and maximum torques will increase with taking the rotor ends than that without rotor ends. A simple model is used to establish the geometry of the rotor ends current density and to investigate the air gap flux density. The magnetic flux is assumed to remain radially constant through the very small air gap length between the sleeve and stator surfaces. Variation of the field in the radial direction is ignored and the skin effect in the axial direction is considered. The axial distributions of the air gap flux density, the sleeve current density components and the force density have been determined. The motor performance is carried out taking into account the effects of the rotor ends on the starting and normal operations. The sleeve rotor resistance and leakage reactance have been obtained in terms of the cylindrical geometry of the machine. These equivalent circuit parameters have been calculated and plotted as functions of the motor speed with and without the rotor ends.
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Whalley, R., and M. Ebrahimi. "Torsional Vibrations in Rotor Shells." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 212, no. 4 (1998): 263–76. http://dx.doi.org/10.1177/095440629821200402.
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Rotors comprising a motor-driven thin cylindrical shell with rigidly attached ends and torsional dampers, all of which are supported on bearings, are investigated. Analysis procedures enabling the variations in the model singularities with parameter changes are outlined. General results are derived indicating that the system damping ratio is maximized under specific operating conditions. A typical high-speed rotor for a paper manufacturing process is considered and analytical and simulation results are presented, confirming the predicted optimum damper settings and thereby minimizing the transient oscillations.
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de Santiago, O., L. San Andre´s, and J. Oliveras. "Imbalance Response of a Rotor Supported on Open-Ends Integral Squeeze Film Dampers." Journal of Engineering for Gas Turbines and Power 121, no. 4 (1999): 718–24. http://dx.doi.org/10.1115/1.2818532.
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Rotor vibration attenuation and structural components isolation in jet engines are achieved with squeeze film dampers, many of them supported on long elastic squirrel cages. Integral squeeze film dampers (ISFDs) are comprised of arcuate pads and wire-EDM webs rendering a compact viscoelastic support. An experimental study is conducted to evaluate the effectiveness of ISFDs in attenuating the imbalance response of a massive test rotor. Measurements of the damper structural stiffness and rotor natural frequencies are detailed. Impact tests on the test rotor supported on its dampers reveal the supporting structure to be very flexible, thus requiring the experimental evaluation of an equivalent stiffness for the damper and supports system. System damping coefficients extracted from impact load excitations vary with the lubricant viscosity and include a significant structural damping from the bearing supports. Rotor coast-down tests demonstrate the ISFDs to damp well the rotor response with peak vibration amplitude proportional (linear) to the imbalance. Viscous damping coefficients estimated from the amplitude response at the critical speeds agree reasonably well with predictions from a full-film, finite element model.
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Zhao, Fang, Jun Ming Zhang, Wei Wang, and De Rong Duan. "Research on the Load Distribution of Throwing Ends in Vertical Shaft Impact Crusher." Advanced Materials Research 156-157 (October 2010): 1463–66. http://dx.doi.org/10.4028/www.scientific.net/amr.156-157.1463.
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With ADAMS dynamics software to simulate the stone movement in the vertical shaft impact crusher rotor, the law of an impact frequency and load on the throwing ends with the variation of feed size and rotor speed is studied, the reasons that the middle throwing end is most vulnerable to wear failure and the rotor speed is not as high as possible are explained.
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Recalde-Camacho, L., W. Leithead, L. Morgan, and A. Kazemi Amiri. "Controller design for the X-Rotor offshore wind turbine concept." Journal of Physics: Conference Series 2767, no. 3 (2024): 032050. http://dx.doi.org/10.1088/1742-6596/2767/3/032050.
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Abstract This paper explores the design of a full envelope speed controller to operate the X-Rotor Offshore Wind Turbine. The X-Rotor is a heavily modified V-rotor vertical axis wind turbine, in which the primary rotor has conventional blades angled both up and down from the ends of a relatively short and stiff cross-arm. The upper half employs full span blade pitching for speed regulation and the lower half is aimed at reducing overturning moments on the main bearing and provides power take-off through compact secondary horizontal axis turbines mounted at the tip of the lower blades. The operational strategy is somewhat similar to that of a variable speed pitch regulated horizontal axis wind turbine, however it differs in the following aspects: the way aerodynamic torque is balanced across the operating envelope, the adjustment of equilibrium operating points at below rated operation, the relationship of aerodynamic torque on the primary rotor to pitch angle, and the operation of the secondary rotors to increase energy capture. These aspects increase the complexity of the control strategy but also ease the controller requirements. The developed controller is tested on a turbine model with sufficient complexity to model the essential dynamic properties of the turbine concept.
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Roy, Haraprasad, Abhinav Khare, Saurabh Chandraker, and J. K. Dutt. "Fatigue based design and life estimation of viscoelastic rotors." Aircraft Engineering and Aerospace Technology 90, no. 1 (2018): 96–103. http://dx.doi.org/10.1108/aeat-01-2015-0015.
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Purpose High-speed rotor subjected to cyclic stress during operation may cause fatigue failure. Thus, the design of a rotor-shaft should involve the fatigue analysis for predicting safe life. Design/methodology/approach A damped rotor shaft with a centrally mounted disc, which is simulated as steam turbine rotor, is considered for fatigue analysis. The shaft is subjected to thermal load and axial torque. It is supported by two orthotropic flexible bearings at its two extreme ends. The bearings are modelled with two-element Voigt model along each orthogonal direction to consider the elastic damped behaviour. Finite element modelling is done through Rayleigh beam theory, where each element is also considered as a Voigt model. The mathematical model involves effect of external axial torque, softening and compressive action of the shaft due to thermal load by the high temperature steam. Findings This paper attempts to find dynamic stresses in a viscoelastic rotor-shaft subject to combined bending and torsional loading and is exposed to thermal environment during operation. The dynamic stress is then used to determine fatigue and also the life of rotors. Research limitations/implications Internal damping plays an important role in deciding dynamic behaviour of rotor shaft systems. Because of this, the rotor shaft becomes unstable after a certain spin speed. Thus, the design of the rotor based on fatigue analysis is limited to the stable zone. Practical implications For this purpose, equations of whirl motion of a viscoelastic rotor-shaft are first obtained after discretizing the continuum with finite beam elements and then the time domain solution of rotor displacement is used to find the bending stress and shear stress at various locations of the rotor. Location for the maximum stress decides the failure point. Safe rotor dimensions have been predicted by comparing dynamic stresses with the Soderberg diagram. Originality/value Design of rotor for safe life operation and prediction of stability could serve a good reference for designers.
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Glinka, Tadeusz, and Jakub Bernatt. "Asynchronous slip-ring motor synchronized with permanent magnets." Archives of Electrical Engineering 66, no. 1 (2017): 199–206. http://dx.doi.org/10.1515/aee-2017-0015.
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Abstract The electric LSPMSM motor presented in the paper differs from standard induction motor by rotor design. The insulated start-up winding is located in slots along the rotor circumference. The winding ends are connected to the slip-rings. The rotor core contains permanent magnets. The electromechanical characteristics for synchronous operation were calculated, as were the start-up characteristics for operation with a short-circuited rotor winding. Two model motors were used for the calculations, the V-shaped Permanent Magnet (VPM) – Fig. 3, and the Linear Permanent Magnet (IPM) – Fig. 4, both rated at 14.5 kW. The advantages of the investigated motor are demonstrated in the conclusions.
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Muszynska, Agnes. "Transition to Fluid-Induced Limit Cycle Self-Excited Vibrations of a Rotor and Instability Threshold “Hysteresis”." International Journal of Rotating Machinery 5, no. 2 (1999): 123–33. http://dx.doi.org/10.1155/s1023621x99000111.
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The transient process which starts at the instability threshold of a rotor rotating in a fluid environment, and ends up in the limit cycle of self-excited vibrations known as fluid whirl or fluid whip, is discussed in this paper. A one-lateral-mode, isotropic, nonlinear model of the rotor with fluid interaction allows for exact particular solutions and an estimation of the transient process. The fluid interacting with the rotor is contained in a small radial clearance area, such as in bearings, seals, or rotor-to-stator clearances, and its effects are represented by fluid film radial stiffness, damping, and fluid inertia rotating at a different angular velocities.The effects of fluid damping and fluid inertia circumferential velocity ratios on the rotor startup and shutdown instability threshold differences are also discussed.
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Kheder, Ahmed Samir, M. A. Elwany, and A. B. Kotb. "Analysis of Disc Motor with Asymmetrical Conducting Rotor." International Journal of Electrical and Electronics Research 12, no. 2 (2024): 487–92. http://dx.doi.org/10.37391/ijeer.120221.
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The homogenous disc rotor construction allows higher rotational speeds and relatively higher power densities. This paper deals with a two-phase induction motor with homogenous disc rotor construction. The field analysis of an axial flux disk motor with a conducting disc rotor is carried out, using a new application of the Maxwell's field equations. A Suggested model is introduced to establish the geometry of motor construction and to enable the derivation of the field system differential equations. A new strategy is applied for the boundary conditions to complete the field solution. This is carried out by determining the complex integration constants. The current density is completely derived with it is components (the radial, the tangential current density and the axial air gap flux density). The performance of the flux density, rotor current components and the torque-slip characteristics are determined with and without disk rotor ends. The effects of the disk rotor design data and the rotor asymmetry on the motor performance are investigated.
Dissertations / Theses on the topic "Rotor ends"
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Samadli, Vugar. "Rotor-bearing system dynamics of a high-speed micro end mill spindle." [Gainesville, Fla.] : University of Florida, 2006. http://purl.fcla.edu/fcla/etd/UFE0015756.
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Hartland, Jonathan. "Secondary loss reduction in rotor blades by non-axisymmetric end-wall profiling." Thesis, Durham University, 2001. http://etheses.dur.ac.uk/1665/.
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Rabe, Douglas Cameron. "Shock wave end wall boundary layer interaction in a transonic compressor rotor." Diss., Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/49872.
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The passage shock wave end wall boundary layer interaction in a transonic compressor was investigated with a laser transit anemometer. A two stage transonic compressor designed without inlet guide vanes was used in this flow field investigation. Measurements of the flow velocity were made within the first stage rotor passage of this transonic compressor. Laser measurements were made in two blade passages at six axial locations from 10% of the axial blade chord in front of the leading edge to 30% of the axial blade chord into the blade passage. At three of these axial locations, laser traverses were taken at different radial immersions to investigate the flow behavior near the tip end wall. Twenty-six different locations were traversed circumferentially. The measurements reveal that the end wall boundary layer in this region is separated from the core flow by what appears to be a shear layer where the passage shock wave and all ordered flow seem to end abruptly.<br>Ph. D.<br>incomplete_metadata
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Macdonald, John Charles. "Efficient Estimation for Small Multi-Rotor Air Vehicles Operating in Unknown, Indoor Environments." BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3496.
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In this dissertation we present advances in developing an autonomous air vehicle capable of navigating through unknown, indoor environments. The problem imposes stringent limits on the computational power available onboard the vehicle, but the environment necessitates using 3D sensors such as stereo or RGB-D cameras whose data requires significant processing. We address the problem by proposing and developing key elements of a relative navigation scheme that moves as many processing tasks as possible out of the time-critical functions needed to maintain flight. We present in Chapter 2 analysis and results for an improved multirotor helicopter state estimator. The filter generates more accurate estimates by using an improved dynamic model for the vehicle and by properly accounting for the correlations that exist in the uncertainty during state propagation. As a result, the filter can rely more heavily on frequent and easy to process measurements from gyroscopes and accelerometers, making it more robust to error in the processing intensive information received from the exteroceptive sensors. In Chapter 3 we present BERT, a novel approach to map optimization. The goal of map optimization is to produce an accurate global map of the environment by refining the relative pose transformation estimates generated by the real-time navigation system. We develop BERT to jointly optimize the global poses and relative transformations. BERT exploits properties of independence and conditional independence to allow new information to efficiently flow through the network of transformations. We show that BERT achieves the same final solution as a leading iterative optimization algorithm. However, BERT delivers noticeably better intermediate results for the relative transformation estimates. The improved intermediate results, along with more readily available covariance estimates, make BERT especially applicable to our problem where computational resources are limited. We conclude in Chapter 4 with analysis and results that extend BERT beyond the simple example of Chapter 3. We identify important structure in the network of transformations and address challenges arising in more general map optimization problems. We demonstrate results from several variations of the algorithm and conclude the dissertation with a roadmap for future work.
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Bílek, Vladimír. "Elektromagnetická analýza a modelování asynchronního stroje s plným rotorem." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2021. http://www.nusl.cz/ntk/nusl-442791.
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Tato diplomová práce se zabývá elektromagnetickou analýzou a modelováním asynchronního stroje s plným rotorem. Tato práce tedy zahrnuje literární rešerši na téma vysokootáčkových elektrických strojů s porovnáním s klasickými elektrickými stroji s převodovkou a popisem jejich výhod či nevýhod, rozdělení vysokootáčkových elektrických strojů s plnými rotory a srovnání jejich výhod či nevýhod, kde se tato práce nejvíce soustřeďuje na vysokootáčkové asynchronní stroje s plnými rotory a jejich použití v průmyslu. Dále se tato práce zabývá metodami výpočtu elektrických asynchronních strojů s plnými rotory. Proto jsou zde uvedeny a popsány metody výpočtu stroje mezi které patří analytické metody i metoda konečných prvků. Vzhledem k povaze elektrických strojů s plnými rotory je hlavně kladen důraz v této práci na výpočet stroje pomocí metody konečných prvků ve 2D prostoru s využitím korekčních činitelů konců plných rotorů, které jsou zde velmi detailně popsány a rozděleny. Na základě dostupné literatury je vypočítaný elektrický stroj s plným rotorem pomocí MKP analýzy. Elektromagnetický výpočet stroje je automatizován pomocí skriptu vytvořeného v Pythonu. Dalším hlavním cílem této práce je popis tzv. náhradních modelů, uvedení jejich výhod či nevýhod, použití v jiných průmyslových odvětvích a hlavně použití náhradních modelů na elektrický stroj s plným rotorem. S využitím náhradních modelů je dále optimalizovaný vybraný asynchronní stroj s plným rotorem a to pomocí programů SymSpace a Optimizer. Pro samotnou optimalizaci byly uvažovány 3 návrhy stroje, které byly na závěr mezi sebou porovnány a to hlavně z hlediska jejich elektromagnetického výkonu.
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Ha, Monica, and Johanna Bångsbo. "Från textil soldatutrustning till garn : En studie av möjligheter till mekanisk återvinning och garnspinning av klädesplagg från FMV." Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-23823.
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Varje år kasserar Försvarets materielverk (FMV) en stor mängd av soldatutrustning av textil. Den textila soldatutrustningen kasseras med anledning att den inte längre går att laga eller har förlorat sin funktion och skickas därmed till förbränning. I enlighet med FMV:s miljöpolicy 2020 vägs ekonomiska och tekniska krav mot mer hållbara alternativ för att bli en mer miljömässigt hållbar verksamhet. Med avsikt att ytterligare utveckla sitt hållbarhetsarbete vill FMV utreda möjligheterna till textilåtervinning för att förlänga livslängd av textila material ytterligare. Därav har denna rapport behandlat mekanisk återvinning av textila soldatutrustningar samt garnspinning av återvunna fibrer. Arbetets bedrivs med syfte att redogöra en studie på uppdrag av FMV med fokus på möjligheter till hur mekanisk återvinning genomförs av textila soldatutrustning och hur garn kan spinnas av fibrer från återvunna fibrer. Genom en litteraturstudie har faktorer som påverkar mekanisk återvinning av textila material samt lämpliga garnspinningsmetoder för återvunna fibrer undersökts i detta arbete. En analys har även genomförts med fokus på fyra klädesplagg fån FMV: skjorta, t-tröja, långkalsong, och stickad tröja. De parametrar som i högsta grad behöver tas hänsyn till för att uppnå så hög garnkvalité är fiberblandning, samt inställningar för spinning, sträckning och kardning. Vid garnspinning är fiberlängden av stor betydelse och därav behöver den mekaniska återvinningen utföras på ett så skonsamt sätt som möjligt för att minska fiberslitaget. För att spinna garn av återvunna fibrer är rotorspinning och friktionsspinning de mest lämpliga metoder, men garnet som produceras har en hög grovlek. För en högre garnkvalité behövs en blandning av jungfruliga fibrer med återvunna fibrer för ett mer tillfredsställande resultat.<br>Each year, Försvarets Materielverk (FMV) discards a massive amount of textile soldier equipment no longer possible to repair and unqualified to use and are therefore incinerated. In accordance with FMV:s policy for environmental sustainability 2020, economic and technical requirements have to be considered in relation to more sustainable alternatives in order to become a more environmentally sustainable organization. With the purpose to further develop towards more sustainable practices, FMV are interested in investigating the possibilities for mechanical textile recycling and yarn spinning of the re-cycled fibers to extend the life cycle of textile materials. The report’s goal was to focus on possibilities and challenges considering the following garments assigned by FMV: t-shirt, knitted sweater, shirt and thermal underwear. The method is based on a literature study and examination of the garments.Conclusions drawn from the study are that fiber blend and settings for carding, drawing and spinning are crucial to produce yarn of high quality. Especially the fiber length has an impact on the possibilities of yarn spinning since it needs to be long enough. To spin yarns from recycled fibers, open-end spinning methods such as rotor spinning and friction spinning are the most suitable. Furthermore, recycled fibers need to be blended with virgin fibers to enable spinning.
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Adabi, Firouzjaee Jafar. "Remediation strategies of shaft and common mode voltages in adjustable speed drive systems." Thesis, Queensland University of Technology, 2010. https://eprints.qut.edu.au/39293/1/Jafar_Adabi_Firouzjaeel_Thesis.pdf.
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AC motors are largely used in a wide range of modern systems, from household appliances to automated industry applications such as: ventilations systems, fans, pumps, conveyors and machine tool drives. Inverters are widely used in industrial and commercial applications due to the growing need for speed control in ASD systems. Fast switching transients and the common mode voltage, in interaction with parasitic capacitive couplings, may cause many unwanted problems in the ASD applications. These include shaft voltage and leakage currents.
One of the inherent characteristics of Pulse Width Modulation (PWM) techniques is the generation of the common mode voltage, which is defined as the voltage between the electrical neutral of the inverter output and the ground. Shaft voltage can cause bearing currents when it exceeds the amount of breakdown voltage level of the thin lubricant film between the inner and outer rings of the bearing. This phenomenon is the main reason for early bearing failures.
A rapid development in power switches technology has lead to a drastic decrement of switching rise and fall times. Because there is considerable capacitance between the stator windings and the frame, there can be a significant capacitive current (ground current escaping to earth through stray capacitors inside a motor) if the common mode voltage has high frequency components. This current leads to noises and Electromagnetic Interferences (EMI) issues in motor drive systems.
These problems have been dealt with using a variety of methods which have been reported in the literature. However, cost and maintenance issues have prevented these methods from being widely accepted. Extra cost or rating of the inverter switches is usually the price to pay for such approaches. Thus, the determination of cost-effective techniques for shaft and common mode voltage reduction in ASD systems, with the focus on the first step of the design process, is the targeted scope of this thesis. An introduction to this research – including a description of the research problem, the literature review and an account of the research progress linking the research papers – is presented in Chapter 1.
Electrical power generation from renewable energy sources, such as wind energy systems, has become a crucial issue because of environmental problems and a predicted future shortage of traditional energy sources. Thus, Chapter 2 focuses on the shaft voltage analysis of stator-fed induction generators (IG) and Doubly Fed Induction Generators DFIGs in wind turbine applications. This shaft voltage analysis includes: topologies, high frequency modelling, calculation and mitigation techniques. A back-to-back AC-DC-AC converter is investigated in terms of shaft voltage generation in a DFIG. Different topologies of LC filter placement are analysed in an effort to eliminate the shaft voltage.
Different capacitive couplings exist in the motor/generator structure and any change in design parameters affects the capacitive couplings. Thus, an appropriate design for AC motors should lead to the smallest possible shaft voltage. Calculation of the shaft voltage based on different capacitive couplings, and an investigation of the effects of different design parameters are discussed in Chapter 3. This is achieved through 2-D and 3-D finite element simulation and experimental analysis.
End-winding parameters of the motor are also effective factors in the calculation of the shaft voltage and have not been taken into account in previous reported studies. Calculation of the end-winding capacitances is rather complex because of the diversity of end winding shapes and the complexity of their geometry. A comprehensive analysis of these capacitances has been carried out with 3-D finite element simulations and experimental studies to determine their effective design parameters. These are documented in Chapter 4. Results of this analysis show that, by choosing appropriate design parameters, it is possible to decrease the shaft voltage and resultant bearing current in the primary stage of generator/motor design without using any additional active and passive filter-based techniques.
The common mode voltage is defined by a switching pattern and, by using the appropriate pattern; the common mode voltage level can be controlled. Therefore, any PWM pattern which eliminates or minimizes the common mode voltage will be an effective shaft voltage reduction technique. Thus, common mode voltage reduction of a three-phase AC motor supplied with a single-phase diode rectifier is the focus of Chapter 5. The proposed strategy is mainly based on proper utilization of the zero vectors.
Multilevel inverters are also used in ASD systems which have more voltage levels and switching states, and can provide more possibilities to reduce common mode voltage. A description of common mode voltage of multilevel inverters is investigated in Chapter 6.
Chapter 7 investigates the elimination techniques of the shaft voltage in a DFIG based on the methods presented in the literature by the use of simulation results. However, it could be shown that every solution to reduce the shaft voltage in DFIG systems has its own characteristics, and these have to be taken into account in determining the most effective strategy.
Calculation of the capacitive coupling and electric fields between the outer and inner races and the balls at different motor speeds in symmetrical and asymmetrical shaft and balls positions is discussed in Chapter 8. The analysis is carried out using finite element simulations to determine the conditions which will increase the probability of high rates of bearing failure due to current discharges through the balls and races.
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Wei, Hsin-Jung, and 魏杏容. "A Study on Processing Parameters Optimization and Quality Characteristic Prediction for Open-End Rotor Spinning Frame." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/40271758546977753668.
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碩士<br>國立臺灣科技大學<br>高分子工程系<br>92<br>The spinning frame to carry out the optimal combination of processing parameter is very important for textile industry. In this thesis, high cleanliness Lyocell cellulose staple was applied for open-end rotor spinning yarn with Ne 32’s. In order to find out the optimal combination of processing parameters, Taguchi experimental method was applied with orthogonal array in the selection of processing parameters for open-end rotor spinning frame. In this case, the optimal processing parameters under steady spinning conditions are take-up speed 91.032 m/min, draft roller speed 91.614 m/min, feed speed 0.437 m/min and rotor speed 60,000 r.p.m. The back propagation neural network was employed to predict the corresponding processing parameters during the operation as well. The efficiency of this research can be shown from the experiments.
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Chen, Hwang-Kuen, and 陳煌坤. "The Influence of End Loads and Cracks on the Whirl Speeds and Stability of a Rotor System." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/73156404185267674585.
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博士<br>國立成功大學<br>機械工程研究所<br>83<br>The stability types and variations of natural whirl speeds of a
rotor system subjected to the end loads (an axial compressive
force, moment, semi-tangential torque and quasi- tangential
torque) are studied in the first part of this thesis. Also, the
critical spin speeds of the rotor system are predicted by using
two methods, whirl frame analyses and Newton-Raphson method.
The influences of an existing crack of the shaft on the dynamic
characteristics of the system will be discussed in the second
part of this thesis and then the charts of the instability of
the system are plotted. A consistent derivation of the
equations of motion in an inertial frame is presented, and then
equations of motion in the spin frame or whirl frame are
obtained by a suitable coordinates transformation. A finite
element model of Timoshenko beam is adopted to approach the
continue shaft part, and the important factors such as rotatory
inertia, shear deformations and gyroscopic effects are taken
into account. The existing crack results in a local flexibility
of the shaft and it will be replaced by a set of springs based
on the balance of energy. The results show that the instability
types of the rotor system due to different end loads are not
the same when the loads reach the critical values. The natural
whirl speeds of the shaft do not always decrease when the loads
increase. Additional instability regions of the shaft''s spin
speed are observed when a crack occurs on the shaft. The
effects of the crack on the whirl speeds of the forward modes
are important than that of the backward modes. The influences
of the crack on the stability of the system are significant as
the depth increases to an evident value.
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Hove, Mazviita. "Development of an empirical model for the prediction of a frictional interaction factor from parameters of the fiber separation section of the open-end rotor yarn spinning machine." 1990. http://hdl.handle.net/1993/16987.
Full textBooks on the topic "Rotor ends"
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Vaez-Zadeh, Sadegh. Machine Modeling. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198742968.003.0002.
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This chapter presents dynamic and steady-state modeling of permanent magnet synchronous (PMS) machines with the help of reference frames. The modeling starts with a machine model in terms of phase variables. An equivalent two-axis model in a stationary reference is then obtained by a reference frame transformation. A further transformation to a two-axis rotor reference frame, with its direct axis aligned with the axis of a permanent magnet rotor pole, is derived. Another transformation to a two-axis stator flux linkage reference frame is also presented. Finally, a motor model in polar coordinates, based on space vector theory, is developed. In this chapter, PMS motor equivalent circuits are drawn, based on the mathematical models where appropriate. Iron losses and iron saturation are also taken into the models. The chapter ends with a brief presentation of the dynamic equation of PMS machines mechanical parts.
Book chapters on the topic "Rotor ends"
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San Andrés, Luis, Sung-Hwa Jeung, and Gary Bradley. "Dynamic Forced Performance of Short Length Open-Ends Squeeze Film Damper with End Grooves." In Proceedings of the 9th IFToMM International Conference on Rotor Dynamics. Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-06590-8_70.
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Atepor, L., F. Davis, and P. M. Akangah. "Experimental Investigations of the Flexible Rotor System by Introducing Parametric Excitations into Both Ends of the Rotating Shaft Axially." In Sustainable Education and Development – Making Cities and Human Settlements Inclusive, Safe, Resilient, and Sustainable. Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-90973-4_23.
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Vas, Peter. "Steady-State and Transient Operation Of Induction Machines and Induction Motor Drives." In Electrical Machines and Drives. Oxford University PressOxford, 1993. http://dx.doi.org/10.1093/oso/9780198593782.003.0003.
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Abstract In Section 2.7.6 a systematic approach for the deduction of various types of electrical machines was presented. It has been shown that a constant electromagnetic torque can be produced by a machine where on the stator there is a symmetrical multi-phase winding excited by symmetrical multi-phase voltages and on the rotor there is a symmetrical multi-phase winding which carries symmetrical multi-phase rotor currents. These requirements can be fulfilled by an induction machine. In an induction machine the air gap can be considered to be uniform if the effects of slotting are neglected. The stator of an induction machine is usually wound with a three-phase winding and on the rotor there is a wound three-phase winding or a squirrel-cage winding. The three-phase stator windings are usually connected in star or delta and the three-phase rotor windings, which have a different number of turns from the stator windings, can also be connected in star or delta, and the ends of the windings are connected to slip rings (slip-ring induction machine). A typical connection is shown in Fig. 3.1.
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"KAPITEL III: Die Wiedergründung nach dem Ende des Krieges." In Ein rot-roter Sonderweg? Böhlau Verlag, 2011. http://dx.doi.org/10.7788/boehlau.9783412213640.247.
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Roytgarts M., Varlamov Yu., and Smirnov A. "Electromagnetic Computations in the End Zone of Power Turbogenerator." In Studies in Applied Electromagnetics and Mechanics. IOS Press, 2008. https://doi.org/10.3233/978-1-58603-895-3-324.
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The mathematical model and computations results of electromagnetic fields, eddy currents and losses in the construction of the power turbogenerators end zone are presented. Effect of the stator and rotor size relations, geometry of the skewed core end part, shape, sizes and arrangement of stator core screens and pressure plate by the method of numerical experiment are investigated. The results of numerical modeling in designs of powerful turbogenerators are implemented. Computational and test data are compared.
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Khadar, Saad, Mohaned Menzou, and Tahar Abbassi. "A Full-Order Terminal Sliding-Mode Observer-Based Optimal Resistance Estimation for High-Performance Control Applications." In Induction Motors - Latest Research and Applications [Working Title]. IntechOpen, 2024. http://dx.doi.org/10.5772/intechopen.1006065.
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This chapter introduces a sensorless field-oriented control (FOC) method for an induction motor with an open-end winding (IM-OEW). A full-order terminal sliding-mode (FOTSM) observer is proposed to accurately estimate the rotor flux, motor speed, and stator currents. The work presented in this chapter endeavors to elevate the sensorless control of the researched IM-OEW topology and fortify its ability to withstand parameter variations. Therefore, an estimation method has been developed to ascertain both the stator and rotor resistance during motor operation, thus contributing to the advancement of the sensorless FOC technique’s exceptional performance and reducing system uncertainties. Combining the resistance estimation approach with the suggested control improves both speed estimates and control accuracy, especially at low speeds. The simulation results produced validate the improved performance and evident effectiveness of the developed control method in a range of various operating scenarios.
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Petrovic Lj., Binder A., Deak Cs., Irimie D., Reichert K., and Purcarea C. "Numerical Methods for Calculation of Eddy Current Losses in Permanent Magnets of Synchronous Machines." In Studies in Applied Electromagnetics and Mechanics. IOS Press, 2008. https://doi.org/10.3233/978-1-58603-895-3-116.
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Eddy current losses in rotor permanent magnets (PM) of synchronous machines are calculated for sinusoidal stator currents and for PWM inverter supply. Three calculation methods are compared in the FE environment: a) time-stepping method, b) quasi-static method, c) semi-analytical post-processing. These 2D methods are with end effect coefficients, and they consider the time variation of currents and of the rotor position. Whereas method a) includes the variation of flux-density over the magnet cross section and the reaction field of the eddy currents, method b) is neglecting the reaction field. Method c) in several variants features either neglecting of the eddy current reaction field or an averaging of the flux density along the magnet width or height. Neglecting the reaction field is possible for materials with low conductivity and low permeability like rare-earth magnets for low to medium frequencies up to several kHz. The quasi-static methods need less computation time, but depend on the machine geometry like stator MMF wave length, slot pitch, segmented vs. massive magnets and small or big magnet height. The comparison of methods a), b), c) is given for two different stator geometries of permanent magnet synchronous machines with open vs. semi-closed slots and surface-mounted vs. buried magnets.
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Lokhande, Yogita. "Centrifuge." In Bio Instrumentation: Tools and Techniques. Iterative International Publishers, Selfypage Developers Pvt Ltd, 2024. http://dx.doi.org/10.58532/nbennurbich2.
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Centrifugation is a process used to separate particles from a solution based on their size, shape, density, medium viscosity and rotor speed using centrifugal force. The denser particles tend to move along the length of the tube to a greater radius of rotation, displacing the lighter particle to the proximal end. It is carried out with an apparatus called centrifuge. A centrifuge is a device for separation of microbes from the suspended fluid using centrifugal force or gravitational force. The word centrifugal force isoriginated from Latin word centrum, meaning ―center‖, and fugere, means ―to flee. The speed of centrifuge is denoted as rpm or revolutions per minute.
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Matt, Daniel, and Nadhem Boubaker. "Very Low Voltage and High Efficiency Motorisation for Electric Vehicles." In Emerging Electric Machines - Advances, Perspectives and Applications. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.95832.
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This chapter details the design of a new innovative solid bar winding for electrical machines (either motors or generators) dedicated to the electric propulsion. The goal of this new winding technique is to enhance the performance by better utilizing the stator slot and increasing the copper fill factor to higher than 75%, and also to reduce the inactive copper at the end-windings. Accordingly, many advantages arise from the application of this solid bar winding: higher torque-to-weight ratio, better thermal behavior, lower rotor losses, higher efficiency, higher reliability and lower cogging torque. However, the solid bar has its inherent constraints, which should be considered with care when designing an electric motor: the AC copper losses and the manufacturing process. The suggested winding technique aims at addressing these challenges.
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Liu, Qunying, Haifeng Zeng, Shaojian Ni, Bowen Li, Jingsong Meng, and Yiguo Zhang. "Design of Power Grid Intelligent Patrol Operation and Maintenance System Based on Multi-Rotor UAV Systems." In Studies in Applied Electromagnetics and Mechanics. IOS Press, 2020. http://dx.doi.org/10.3233/saem200011.
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Complex geographical conditions and bad weather have caused great difficults to inspect transmission line of power grids. This work aims to develop a micro multi-rotor Unmanned Aerial Vehicle (UAV) system for inspecting power grid. The proposed system integrates with an intelligent robot and mobile communication networks. The high-resolution aerial images of the inspection line can be obtained to improve the operational efficiency and safety. The time period from the front-end signal acquisition to terminal decoding and playback is 1.5s for condition-based maintenance. The system supports TDD-LTE, FDD-LTE, WCDMA, CDMA2000, and other network standards. It also supports the video input signals with the resolution of standard 576i, HD 720p, FHD 1080i, and FHD 1080p. It is compatible with a variety of transmission formats and codes, help to achieve timely, comprehensive and efficient high-resolution aerial image acquisition of patrol lines, and improve operational efficiency and safety, real-time monitoring and condition-based maintenance of power transmission lines.
Conference papers on the topic "Rotor ends"
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Tan, Jianfeng, George Barakos, Yiming Sun, Tianyi Zhou, and Richard Green. "Simulation of the Aerodynamic Interaction between Rotor and Ground Obstacle Using Vortex Method." In Vertical Flight Society 74th Annual Forum & Technology Display. The Vertical Flight Society, 2018. http://dx.doi.org/10.4050/f-0074-2018-12841.
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The aerodynamic interaction between rotor wake and surrounding obstacles is complex, and generates high compensatory workload for pilots, degradation of the vehicle handling qualities and performance, and unsteady forces on the structure of the obstacles. The interaction also affects the minimum distance between rotorcraft and obstacles to operate safely. A vortex-based approach is here employed to investigate the complex aerodynamic interaction between rotors and ground obstacles and identify the distance where the interaction ends. This is also one of the objectives of the GARTEUR AG22 effort. In this approach, the aerodynamic loads of the rotor blades are described through a panel method, and the unsteady behavior of the rotor wake is modelled using a vortex particle method. The effects of the ground plane and obstacle are accounted for via a viscous boundary model. The method is then applied to "Large" and "Wee" rotor near the ground and obstacle and compared with earlier experiments carried out at the University of Glasgow. The results show that the predicted rotor induced inflow, and flow-field compare reasonably well with the experiments in terms of magnitude and phase, for the peaks of the radial outwash and vertical downwash. Furthermore, at certain conditions the tip vortices are pushed upwards and are re-ingested into the rotor wake due to the effect of the obstacle resulting in a recirculation. Moreover, contrary to cases without the obstacle, the peak and thickness of the radial outwash near the obstacle is lower due to blockage effects, and an up-wash is observed. Additionally, as the rotor closes to the obstacle, the rotor slipstreams impinge directly on the obstacle, and the up-wash near the obstacle is faster, indicating a stronger interaction between the rotor wake and the obstacle. Also, contrary to the case without the obstacle, the fluctuations of the rotor thrust, roll and pitch moments are obviously strengthened. When the distance between the rotor and the obstacle is larger than 3R, the effect of the obstacle is small.
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Richter, Kai, and Erich Schülein. "Boundary Layer Transition Measurements on Hovering Helicopter Rotors by Infrared Thermography." In Vertical Flight Society 70th Annual Forum & Technology Display. The Vertical Flight Society, 2014. http://dx.doi.org/10.4050/f-0070-2014-9435.
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High speed infrared thermography was applied for boundary layer transition measurements on the upper side of helicopter rotors. The transition detection is based on the analysis of a single instantaneous thermal image of the rotating blade and allows the determination of both the locations of the onset and of the end of the transition region. Measurements were performed on a Mach scaled BO105 model rotor for different rotation frequencies. The transition characteristics are presented and compared to two-dimensional numerical simulations, and the measurement scatter is discussed. Additional transition measurements were performed on the main rotors of the DLR research helicopters Eurocopter BO105 and EC135. The transition behavior of the EC135 rotor blade is presented for different cases and the effect of the contamination of the rotor blade leading edge on the laminar flow is discussed.
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Schatzman, Natasha, Athena Chan, Michael Fillman, et al. "Performance Analysis and Data Processing for the Mars Sample Recovery Helicopter in the Jet Propulsion Laboratory 25-ft Space Simulator." In Vertical Flight Society 80th Annual Forum & Technology Display. The Vertical Flight Society, 2024. http://dx.doi.org/10.4050/f-0080-2024-1357.
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On April 19, 2021, Ingenuity became the first helicopter to fly on Mars at Jezero Crater, completing a total of 72 flights by the end of its mission. The success of Ingenuity resulted in various research efforts to further exploreMars via vertical flight, including two optimized Ingenuity-sized helicopters proposed to retrieve samples for the 2028 Mars Sample Return mission. To aid in the design process for the two proposed Sample Retrieval Helicopters, both heritage and optimized, increased diameter rotors were tested at the NASA Jet Propulsion Laboratory in the 25-ft Space Simulator. Three test campaigns were performed using the Ingenuity rotors and optimized Sample Retrieval Helicopter (SRH) rotors for several rotor speeds, densities, configurations, and collectives to identify performance limitations. These three test campaigns included the Ingenuity Engineering Design Model 1 (EDM-1) with and without a cruciform box, Transonic Rotor Test (TRT) rig, and SRH Dual Rotor Test (DRT). Experimental setup, test matrix, data processing, data quality, and performance results for EDM-1, TRT, and DRT campaigns are presented and discussed. Experimental results from the test campaigns will aid in future experimental methods and validation efforts for planetary rotorcraft exploration.
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van Gestel, Ron, and Sjef Mattheij. "Rotor Repairs." In ASME 1994 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1994. http://dx.doi.org/10.1115/94-gt-351.
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Often, turbine and generator rotors are produced from a single forging or from two forged bearing ends with a stack of discs in between. As with many other components in rotary equipment these precision machined forgings can be damaged or worm during operation. Due to the sensitivity of the material to any kind of heat treatment, including welding, repair of this damage presents a challenge for repair engineers. This paper will give a general overview of repair. Repair may include welding, heat treatment, plasma spraying, shaft straightening, stress relieving, etc. Some recent repairs will be discussed.
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de Santiago, Oscar, Luis San Andrés, and Juan Oliveras. "Imbalance Response of a Rotor Supported on Open-Ends Integral Squeeze Film Dampers." In ASME 1998 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/98-gt-006.
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Rotor vibration attenuation and structural components isolation in jet engines are achieved with squeeze film dampers, many of them supported on long elastic squirrel cages. Integral squeeze film dampers (ISFDs) are comprised of arcuate pads and wire-EDM webs rendering a compact viscoelastic support. An experimental study is conducted to evaluate the effectiveness of ISFDs in attenuating the imbalance response of a massive test rotor. Measurements of the damper structural stiffness and rotor natural frequencies are detailed. Impact tests on the test rotor supported on its dampers reveal the supporting structure to be very flexible, thus requiring the experimental evaluation of an equivalent stiffness for the damper and supports system. System damping coefficients extracted from impact load excitations vary with the lubricant viscosity and include a significant structural damping from the bearing supports. Rotor coast-down tests demonstrate the ISFDs to damp well the rotor response with peak vibration amplitude proportional (linear) to the imbalance. Viscous damping coefficients estimated from the amplitude response at the critical speeds agree reasonably well with predictions from a full-film, finite element model.
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Jafri, Syed Muhammad Mohsin, and John M. Vance. "Shrink Fit Effects on Rotordynamic Stability: Experimental Study." In ASME Turbo Expo 2008: Power for Land, Sea, and Air. ASMEDC, 2008. http://dx.doi.org/10.1115/gt2008-50410.
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This paper presents an experimental study of internal friction effects on two different test rotors with shrink fit and interference fit joints. One of the setups was a single-disk rotor with an interference fit joint to the main shaft through a mechanically adjustable tapered sleeve; the other setup was a two-disk rotor with a variable cross-section shaft, having the two disks shrunk fit into an aluminum sleeve at the ends. The slippage in these types of joints is known to be a potential source of sub-synchronous rotordynamic instability in rotating machines. The experimental results from the rotor setups show the presence of strong unstable sub-synchronous rotor vibrations initiated at operating speeds above the first critical speeds of the rotor-bearing systems. The experiments with the two-disk rotor demonstrated that different distributions of shrink fit at two locations (loose fit at one end; tight fit at the other end) were necessary to produce rotordynamic instability. The instability in that case caused complete wreckage of the test rig, showing that the sub-synchronous vibrations caused by slippage at interference fit joints are potentially dangerous to the safe operation of rotating machines. Furthermore, a critical radial interference (shrink fit) of 1 mils (25.4 μm) at speed was identified to cause an onset of instability in several of the experiments.
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Yu, John J. "On Two-Plane Balancing of Symmetric Rotors." In ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/gt2012-68061.
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When rotor balancing is performed in the field, minimum trial weight runs would significantly reduce the downtime in power generation and oil-gas industries. Typically two trial weight runs would be required in order to obtain both static and couple influence coefficients. The current paper demonstrates how both static and couple influence coefficients can be evaluated with high accuracy through merely one trial weight run on symmetric rotors. It is shown through real cases that, for symmetric rotors such as double-flow low-pressure (LP) turbine and generator rotors, cross effects between static weights (placed in-phase at two ends) and couple response (the same vibration amplitude but 180 degrees out-of-phase at two ends) are minimal and can be neglected. The same holds true for coupled weights (placed 180 degrees out-of-phase at two ends) and static response (the same vibration amplitude inphase at two ends). Real cases show that static and couple influence coefficients for symmetric rotors obtained from the one trial weight run are very close to the true values from the two trial weight runs or the classical static/couple approach. From the calculated static and couple influence data through one trial weight run, final balance weights for reducing static or couple response only or their combination can be determined successfully.
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Nobahari, Amin, Abolfazl Vahedi, and Farshid Mahmouditabar. "Torque Profile Improvement of a Synchronous Reluctance Motor through Optimizing the Rotor Flux Barriers Ends." In 2019 International Power System Conference (PSC). IEEE, 2019. http://dx.doi.org/10.1109/psc49016.2019.9081540.
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Yu, John J., and Siddharth Ashar. "Effect of Higher-Than-Rated-Speed Rotordynamic Modes on Rotor Balancing." In ASME Turbo Expo 2015: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/gt2015-43405.
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It was surprisingly reported that a generator rotor could not be balanced to an acceptable vibration level by weights at two balance planes at the drive end (DE) and the non-drive end (NDE) fan rings. Both real measured vibration data and rotordynamic calculations indicate that the rotor at rated speed of 3600 rpm appears to run just above the 2nd critical speed (couple or conical mode). However, couple weights (same weights placed at both DE and NDE with 180-degree-out-of-phase) have little effect on 1X vibration response. A third balance plane had to be utilized to effectively reduce vibration. This paper uses measured data and rotordynamic modelling to explain these findings. It is found that the 4th mode could affect synchronous vibration response at rated speed significantly besides the 3rd mode. The two fan ring balance planes appear to be near the nodal points of the 4th mode, which explains ineffectiveness of the couple weights to vibration response at rated speed in the field. Measured data from real machines including influence vectors are presented from third balance planes such as the coupling and the exciter ends, besides the fan ring wheels. The 3rd and 4th rotordynamic modes are also given along with unbalance response studies.
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Yu, John J. "The Necessity of a Third Balance Plane for Generator Rotor Field Balancing." In ASME Turbo Expo 2014: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gt2014-25706.
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When balancing a generator rotor in the field, one often assumes that two balance planes at the drive end (DE) and non-driven end (NDE) fan rings would be sufficient to bring 1X vibration down. This paper, however, presents a case where a third balance plane must be utilized in order to reduce 1X vibration level below the alarm limit. Though this type of generator with rated speed of 3600 rpm appears to run just above the second couple mode from Bode and polar plots, couple weights (same weights placed at both DE and NDE with 180-degree out-of phase) have little effect on 1X vibration response. For vibration vectors at DE and NDE bearings presenting certain relative phase, it became impossible to further reduce vibration level at both ends from weights at DE and NDE fan ring planes only as indicated in obtained influence data. A third balance plane at the exciter end was attempted to change their relative phase, which proved to be successful. From the exciter end weights combined with the NDE fan ring weights, the generator rotor was balanced successfully. The purpose of this paper is to show in some cases ineffectiveness of couple weights to couple (pivotal mode) response and success of field balancing with a third balance plane on a generator rotor.
Reports on the topic "Rotor ends"
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Grendahl, Scott M., and Marc S. Pepi. Failure Analysis of an AH-64 Main Rotor Damper Blade Rod End, P/N 7-211411186-5. Defense Technical Information Center, 2003. http://dx.doi.org/10.21236/ada421230.
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