Dc Machine
Mostrando 13-24 de 26 artigos, teses e dissertações.
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13. PROJECT, IMPLEMENTATION AND AUTOMATION OF A BENCH FOR TESTING SWITCHED RELUCTANCE MOTORS / PROJETO, IMPLEMENTAÇÃO E AUTOMAÇÃO DE UMA BANCADA PARA ENSAIOS DE MOTORES A RELUTÂNCIA CHAVEADOS
This work presents a proposal for testing Switched Reluctance Motors, which is feasible by the design and construction of an automated test bench. The test proposal intends to measure phases resistance; to compute copper loss; to obtain the magnetizing curves for aligned and unaligned rotor and a performance test, which is based on fixing the under test moto
Publicado em: 2009
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14. Active magnetic bearing applied to a tubular linear induction motor. / Mancal magnético ativo aplicado a um motor de indução linear tubular.
A tubular linear induction motor applied to onshore oil exploitation, named MATÆOS (which is in the Portuguese acronym for Tubular Asynchronous Motor for Onshore Oil Exploitation) was built at Escola Politécnica da Universidade de São Paulo (EPUSP). Its purpose is to directly drive the sucker-rod pump installed in the down hole of the oil well. In continu
Publicado em: 2009
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15. CONTRIBUTION TO THE CONNECTION OF DOUBLY-FED INDUCTION GENERATORS WITH A SERIES GRID SIDE CONVERTER / ANÁLISE DA CONEXÃO DE GERADORES EÓLICOS DUPLAMENTE ALIMENTADOS COM COMPENSAÇÃO SÉRIE
This dissertation addresses the main problems related to doubly-fed induction generators (DFIG) connection to grids with unbalanced voltages. Series compensation is used to achieve balanced voltage on the stator of the machine, avoiding torque oscillations and high currents due to the grid voltage unbalance. The DC-link voltage control proposed reduces the c
Publicado em: 2008
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16. In vitro evaluation of the resistance to traction of different fiber-glass posts used in two protocols for fragile root rehabilitation, with or without composite resin reinforcement / Avaliação, in vitro, da resistência à tração de diferentes pinos de fibra de vidro utilizados em dois protocolos para reabilitação de raízes fragilizadas, com e sem reforço de resina composta
This study evaluated in vitro the resistance of roots to traction of different posts of glass-fiber used in two register to rehabilitation of weakened roots with or out reinforcement of composite resin. Thirty canines had their crowns sectioned and radicular canals endodontically treated. The roots were included in blocks of resin, having exception in 2mm ce
Publicado em: 2008
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17. Influência da dose de energia sobre o grau de conversão, tensão de polimerização, propriedades mecânicas e microinfiltração in vitro de restaurações em compósito / Influence of the radiant exposure on the degree of conversion, polymerization stress, mechanical properties and in vitro microleakage of composite restorations
Proposition: The aim of this study was to verify the influence of radiant exposure applied to a composite on the degree of conversion (DC), polymerization stress (PS), maximum rate of reaction (Rp max), mechanical properties (flexural strength/FS, elastic modulus/E, Knoop hardness/KHN) and microleakage of in vitro restorations using two adhesive systems. Met
Publicado em: 2007
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18. Modelagem e simulação de uma máquina elétrica de corrente contínua levando-se em consideração os efeitos de reação de armadura. / Modeling and simulation od a DC machine taking into account the armature reaction effects.
Acionamentos elétricos em corrente contínua ainda são largamente empregados em plantas industriais. Os modelos usualmente adotados para os motores envolvem diversas simplificações, desprezando os efeitos da reação de armadura. Neste trabalho, foi realizada uma pesquisa bibliográfica a fim de se encontrar modelos matemáticos que contemplassem os efei
Publicado em: 2006
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19. Drive and sensorless control for brushless DC motors applied to hermetic compressors for household refrigeration / Acionamento e controle sensorless para motores brushless DC aplicados a compressores herméticos para refrigeração doméstica
The aim of this work is to develop the simulation of a speed control system for household hermetic compressors using brushless DC motors controlled by a sensorless strategy. The main point of the work is the development of the control global simulation from a suitable BLDC motor model based on Matlab/Simulink program. Some sensorless control strategies and e
Publicado em: 2006
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20. Identificação on-line de motores de indução através de modelo discreto para sinais senoidais
In this work are developed two on-line identification methods for three-phase induction motors based on discrete models obtained when we consider continuous systems excited by sinusoidal signals. The first method uses the discrete model of the homopolar machine in the stationary frame to estimate the stator resistance and the stator dispersion inductance and
Publicado em: 2006
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21. Detecção e diagnóstico de falhas em motores de indução
This main purpose of this work is to design and implement a system to detect and diagnose electrical faults (stator inter-turn short circuit and broken rotor bars) and mechanical faults (unbalance and shaft misalignments) for three phase induction machines. This approach starts by obtaining the best patterns for fault detection and symmetrical models for the
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 08/07/2005
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22. Estimação dos parâmetros da máquina síncrona e seu sistema de excitação / Estimation of the parameter of synchronous machine and its excitation system
In this work a methodology to estimate parameters of synchronous machines and their excitation system based on trajectory sensitivity technique and system synchronization is proposed. Many methodologies for parameter estimation have been proposed in the literature, each one with advantages and desadvantages. However, only some of them are adequate to estimat
Publicado em: 2005
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23. "Relationship between contraction stress and degree of conversion in dental composites" / "Relação entre tensão de contração e grau de conversão em compósitos restauradores"
ABSTRACT The contraction stress developed during polymerization of composites bonded to cavity walls cavity is often associated with marginal gaps and interfacial failure. The aim of this study was to verify the relationship between contraction stress and degree of conversion (DC) in four composites (Z250, A110 3M ESPE; Tetric Ceram, Heliomolar Vivaden
Publicado em: 2003
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24. Control Strategies for Wind Turbines with Induction Generators / EstratÃgias de controle de sistemas de garaÃÃo eÃlica com mÃquinas de induÃÃo
The perspectives of a great number of accesses of wind turbines to the Brazilian electrical system have stimulated studies on the controls of these generators and the impacts that they will cause in the electrical grid. This two stages work, considered the study of control techniques of induction generators with squirrel cage type or doubly fed, when set in
Publicado em: 2003