Made available in DSpace on 2016-01-13T13:26:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-06-01. Added 1 bitstream(s) on 2016-01-13T13:32:13Z : No. of bitstreams: 1 000851683.pdf: 4727436 bytes, checksum: 0bfc744d468181da57a7b13a6d3f2434 (MD5) / Essa dissertação tem por objetivo investigar o comportamento dos parâmetros do motor de indução trifásico (MIT) com rotor tipo gaiola de esquilo, potência mecânica nominal de 3 HP, 220 V, 4 pólos, 60 Hz através das variáveis propostas pela Teoria de Potência Conservativa (CPT), operando sob condições de distúrbios de qualidade de energia. Inicialmente foram determinadas algumas condições de distúrbios, baseadas no Módulo 8 do PRODIST da ANEEL, envolvendo distorções harmônicas de tensão (harmônicas de 3º, 5º e 7º ordem com aplitudes de 6,5%, 7,5% e 6,5% da fundamental respectividade), desequilíbrio de tensão (fator de desequilíbrio de 2% na amplitude, assimetria e ambos), afundamento de tensão (50% da amplitude nas três fases para 5 e 30 ciclos da frequencia da rede) e elevação de tensão (incremento de 50% na amplitude das tensões para 5 e 30 ciclos). Esses distúrbios foram aplicados na alimentação de um motor de indução trifásico em condição de regime permanente com conjugado nominal de carga. O modelo do MTI é representado através da transformação das variáveis de estator e rotor para os eixos d-q num plano de referência síncrono, sendo possível assim verificar o comportamento dinâmico dessa máquina nessas condições. Toda estrutura de simulação e aquisição de dados foi desenvolvida no software PSIM. Através das simulações foi possível avaliar o comportamento dos índices da CPT e a relação existente entre alguns índices e os parâmetros do motor / This dissertation aims to investigate the behavior of three-phase induction motor parameters (MIT) with squirrel cage rotor, mechanical nominal power of 3 HP, 220 V, 4poles, 60 Hz using the variables proposed by the Conservative Power Theory (CPT), operating under conditions of power quality disturbances. initially some disturbance conditions were determined, based in Module 8 of PRODIST ANEEL, involving voltage harmonic distortion (harmonic 3rd, 5th and 7 th order with amplitudes of 6,5% 7.5% and 6.5% of the fundamental respectively), voltage imbalance (2% amplitude imbalance factor, asymmetry, and both), sag (50% of the amplitude in the three phases for 5 and 30 cycles of the mains frequency), and voltage increase (increment 50% in the amplitude of the voltages for 5 and 30 cycles). These disorders were applied to a three-phase induction motor in steady condition with rated torque lead. The MIT model is represented by the transformation of the stator and rotor variables for the dq axes in an synchronous reference frame, permiting the check of the dynamic behavior of this machine in these conditions. Every simulation structure and data aquisition was developed in PSIM software. Through simulations it was possible to evaluate the behavior of the indices of CPT and relationship between some indices and machine parameters

Made available in DSpace on 2014-06-11T19:22:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-12-02Bitstream added on 2014-06-13T19:26:26Z : No. of bitstreams: 1 mancussi_bep_me_bauru.pdf: 1882449 bytes, checksum: 54c196e54f4e861a42f9380fd6e6c42a (MD5) / Os motores monofásicos de indução são dispositivos para produção de força motriz que apresentam baixas potências quando comparados aos motores trifásicos, porém, são largamente utilizados em aplicações domésticas e comerciais. Ao contrário dos motores trifásicos, os motores monofásicos não possuem um campo girante uniforme, mas, um campo magnético pulsante que resulta em conjugado de partida nulo, tornando necessários métodos de partida auxiliares. Além disso, o campo pulsante ocasiona uma operação com conjugado pulsante. A pulsação de conjugado produz vibrações que podem se agravar com a alimentação a partir das fontes não senoidais de tensão. Dessa forma, o objetivo deste trabalho é avaliar experimentalmente a influência de tensões não senoidais sobre as pulsações de conjugado do motor monofásico de capacitor permanente, que opera de maneira semelhante a um motor bifásico desequilibrado e que é um dos modelos mais utilizados em diversas aplicações como refrigeradores e aparelhos condicionadores de ar. Para tanto, foi construída uma bancada de ensaio para observação do motor operando sob diversas condições de alimentação e os resultados experimentais são comparados com aqueles oriundos de simulações numéricas com modelos tradicionalmente utilizados em pesquisas acadêmicas / The single phase induction motors are devices for producing driving force with relatively low power consumption, but widely used in domestic refrigeration systems. Unlike polyphase AC motors, single-phase induction motors have a pulsating magnetic field. For this reason they have a zero starting torque, being necessary to uso auxiliary starting methods, furthemore presenting pulsating torque. The pulsating torque produces vibrations during operation of the engine thay may be worsened with power from non-sinusoidal voltage supply systems. Thus, the aim of this work is to evaluate experimentally the influence of non-sinusoidal voltages exert on the single phase permanent capacitor motor torque pulsations. Therefore was constructed a test facility for observation of the motor operating under different feeding conditions and the experimental results are compared with those from usually mathematical models

Orientador: Renato C. Creppe / Banca: José Alfredo Covolan Ulson / Banca: Diogenes Pereira Gonzaga / Resumo: Os motores monofásicos de indução são dispositivos para produção de força motriz que apresentam baixas potências quando comparados aos motores trifásicos, porém, são largamente utilizados em aplicações domésticas e comerciais. Ao contrário dos motores trifásicos, os motores monofásicos não possuem um campo girante uniforme, mas, um campo magnético pulsante que resulta em conjugado de partida nulo, tornando necessários métodos de partida auxiliares. Além disso, o campo pulsante ocasiona uma operação com conjugado pulsante. A pulsação de conjugado produz vibrações que podem se agravar com a alimentação a partir das fontes não senoidais de tensão. Dessa forma, o objetivo deste trabalho é avaliar experimentalmente a influência de tensões não senoidais sobre as pulsações de conjugado do motor monofásico de capacitor permanente, que opera de maneira semelhante a um motor bifásico desequilibrado e que é um dos modelos mais utilizados em diversas aplicações como refrigeradores e aparelhos condicionadores de ar. Para tanto, foi construída uma bancada de ensaio para observação do motor operando sob diversas condições de alimentação e os resultados experimentais são comparados com aqueles oriundos de simulações numéricas com modelos tradicionalmente utilizados em pesquisas acadêmicas / Abstract: The single phase induction motors are devices for producing driving force with relatively low power consumption, but widely used in domestic refrigeration systems. Unlike polyphase AC motors, single-phase induction motors have a pulsating magnetic field. For this reason they have a zero starting torque, being necessary to uso auxiliary starting methods, furthemore presenting pulsating torque. The pulsating torque produces vibrations during operation of the engine thay may be worsened with power from non-sinusoidal voltage supply systems. Thus, the aim of this work is to evaluate experimentally the influence of non-sinusoidal voltages exert on the single phase permanent capacitor motor torque pulsations. Therefore was constructed a test facility for observation of the motor operating under different feeding conditions and the experimental results are compared with those from usually mathematical models / Mestre

M.Sc. (Mechanical Engineering) / Please refer to full text to view abstract

This thesis describes the implementation of a novel microprocessor-controlled, 4-quadrant DC-to-DC converter for driving a DC servo motor. The converter is supplied from a fixed 28V DC voltage source and the output voltage can be varied throughout the range ±180V.

Biomolecular motor based transport reconstituted in synthetic environment has been recently established as a promising component for the development of nanoscale devices. A minimal system consisting of microtubules propelled over a surface of immobilized kinesin motor proteins has been used to transport and manipulate cargo for molecular sorting, analyte detection, and other novel nanotechnological applications. Despite these achievements, further progress of the field and translation of the reported applications to a real-world setting require overcoming several key challenges, such as, development of effective cargo conjugation strategies and precise control of the transport directionality with the reconstituted biomolecular motor systems. The challenge of cargo conjugation is addressed in this thesis through the development of a robust bioorthogonal strategy to functionalize microtubules. The versatility of the developed method is demonstrated by covalently conjugating various types of cargos to microtubules. Further, the effect of the linker length on cargo attachment to microtubules is investigated by attaching cargo to microtubules via linkers of different lengths. By using kinesin-driven transport of microtubules that are covalently conjugated to antibodies, detection of various clinically relevant analytes is demonstrated as proof-of-principle applications for biosensing. Finally, the challenge of gaining control over transport directionality is addressed through topographical guiding of microtubules in nanostructures, and optimization of assay parameters to achieve successful guiding of microtubules. Spatio-temporal analyte concentration, using transport in these nanostructues, is also explored to make the biomolecular-motor based applications more suitable for use real-world point-of-care setting. Taken together, the experimental work in this thesis contributes to the field of nanotechnological applications of biomolecular motors. The developed microtubule functionalization method and understanding of the effect of cargo attachment via linkers provide useful design principles for efficient cargo loading to microtubules. Moreover, establishment of assay components for successful guiding of microtubules in nanostructures is a vital step forward for practical translation of future nanoscale devices.

A mathematical model which predicts the cooling system performance for a rally car is derived in this study. A case study vehicle was made available by a local manufacturer for evaluation of the cooling system. Two heat exchangers compatible for the vehicle were tested in a controlled wind tunnel environment to determine its heat transfer characteristics. Including the relationship between fluid flows and vehicle speed, a function resulted through which the cooling system performance can be predicted. Including the heat generated by the engine to be dissipated by the cooling system and the effect of ambient conditions on heat generated and dissipated, an energy balance results. Using the energy balance a contour plot is generated which predicts the suitability of the heat exchanger at various ambient conditions. The tool thus allows the user to assess the cooling system on the day of the race, highlighting whether the required cooling will be achieved. / Dissertation (MEng(Mechanical))--University of Pretoria, 2007. / Mechanical and Aeronautical Engineering / unrestricted

The simulation of vehicle engine cooling validation in a Climatic chamber will benefit all vehicle manufacturers that are responsible for the design or the localization of parts used in a vehicle's engine cooling system. The ability to test the vehicle in-house allows testing at any time of the year; it provides repeatable and comparative data, and accelerates component level approval, which in itself reduces program timing and cost. For this dissertation road level testing was conducted in Upington using a TD1200 Superflow towing dynamometer, while the in-house testing was performed on a ROTOTEST chassis dynamometer in a Climatic chamber. All tests were conducted according to GENERAL MOTORS SOUTH AFRICA global testing standards. Statistical analyses of the test data were used to determine the relationship between parameters measured and results obtained. The major contributors to the simulation process was identified and implemented to improve measurement quality and test results. The result was an accurate simulation between road and chamber testing, hence the possibility of moving away from road testing and conduct simulated chamber testing. The presented dissertation is useful for the understanding of basic vehicle cooling testing and the methodology of simulated testing in an environmentally controlled chamber.

M.Ing. / The purpose of this thesis was to gather experimental data of a stainless steel sleeve being formed into a convoluted tube. This convoluted tube, made from stainless steel ASTM 240 type 321 and with a wall thickness of 0,4mm, is the main part of an automotive exhaust bellow. The automotive exhaust bellow fits into a motor vehicle exhaust system. One of the functions of this bellow is to compensate for engine movement. The bellow is also used to damp the engine vibration to the vehicle chassis. Typical failures that occur during the production of a convoluted tube are identified. The data gathered are listed and the forming process, typical conditions and its effects discussed. The actual data and graphs are presented in the annexures at the end of this report. Plasticity theory for shells and cylinders is summarized in Annexure A and the solution of a related problem discussed. Experimental data were used to verify the result of a finite element model. The calculated values of the model compare well with the values of the experimental data. The model must still be developed further and the experimental data can be used to verify this developed model. Possible aspects, related to the forming and life-cycle prediction of an automotive exhaust bellow, that still need to be studied are identified and presented at the end of this report.

No description available.