Electrical Machine
Mostrando 13-24 de 43 artigos, teses e dissertações.
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13. ASPECTOS FISIOLÃGICOS E BIOQUÃMICOS DA MATURAÃÃO DE SEMENTES DE PIMENTÃO. / Physiological and biochemical aspects of the maturation of sweet pepper seeds
The determination of the appropriate point or interval for the harvest of fruits for sweet pepper seed production is fundamental for success in production programming, as well as for obtaining quality seeds. From their physiological maturity period up to the moment they are used for sowing, the seeds are subject to loss of physiological quality due to the oc
Publicado em: 2009
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14. Uso de ferramentas de aprendizado de máquina para prospecção de perdas comerciais em distribuição de energia elétrica / Use of machine learning tools for prospecting commercial losses in electric energy distribution
As concessionárias de energia elétrica deixam de faturar anualmente expressivos valores devido a perdas comerciais, as quais são originadas principalmente por fraudes cometidas por parte dos consumidores e por medidores defeituosos. A detecção automática dos pontos específicos onde ocorrem tais perdas é uma tarefa complexa, dada a grande quantidade d
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 29/01/2008
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15. Hollow cathode discharge: application of a deposition treatment in the iron sintering
The influence of a previous deposition treatment on the final amount of alloying elements (Cr and Ni) deposited and diffused into the surface of iron parts sintered in hollow cathode discharge (HCD) was studied. Cylindrical pure iron pressed samples, being a central cathode, were placed concentrically in the interior of an AISI 310 steel machine-made outer c
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2008-06
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16. Dry material losses and qualitative evaluation of corn grain stored in hermetic units / Determinação da perda de matéria seca e avaliação qualitativa de grãos de milho armazenados em bolsas herméticas
A significant increase in the grain sector has been observed over the last few years, leading to the expansion of the balance of trade. However, in various Brazilian States, storage systems are composed of old structures, precarious for storage which end up compromising the quality of the product during storage. In order for the sector to increase exports an
Publicado em: 2008
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17. The behavior of graphite and copper electrodes on the finish die-sinking electrical discharge machining (EDM) of AISI P20 tool steel
The machining parameter settings installed at CNC EDM machines are developed under optimum process conditions. Standard workpiece and electrode materials are used traditionally by machine manufacturers to establish the EDM parameter settings. However, this is not the usual situation of the tooling industry, where many different grades of workpiece and tool e
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2007-12
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18. Monitoramento permanente de motores de indução trifasicos / On-line monitoring of three-phase induction motors
A predictive maintenance program must include several techniques of monitoring of the electric motors conditions. Among these techniques, probably the two most classic ones are related to electric current and vibration analysis. Unfortunately, in both cases inherent drawbacks make difficult their use in loco on industry plants. As there is a large range of
Publicado em: 2007
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19. Análise do campo magnético de um motor de ímã permanente no rotor utilizando o método dos elementos finitos / Finite element analysis of a permanent magnet motor
Neste trabalho é estudado um motor trifásico de ímã permanente no rotor, com fluxo não senoidal, através da análise do campo magnético. Essa máquina foi projetada utilizando-se a estrutura ferromagnética do estator de um motor de indução monofásico de 24 ranhuras o qual recebeu um novo enrolamento trifásico, e foi construído o rotor que é con
Publicado em: 2007
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20. Uma contribuição à modelagem de complexos eólicos contendo geradores especiais para atenuação das componentes harmônicas
Most of the wind energy conversion systems (WECS) currently in operation in the world use asynchronous generators in the transformation of wind energy into electricity energy. In Brazil, although it is recognized that the parcel of wind farms is still very reduced, it is evidenced that the principle of the employed generation is mainly synchronous. Within th
Publicado em: 2007
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21. Estimativa do comportamento de máquinas assíncronas sujeitas a afundamentos de tensão
Os afundamentos de tensão são reduções de curta duração entre o 10% a 90% da magnitude de tensão eficaz. Usualmente, estes afundamentos são associados com falhas no sistema de energia elétrica, mas podem ser causados pela elevada corrente de partida de motores de indução ou energização de transformadores. Apesar de sua curta duração, tais even
Publicado em: 2007
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22. Bacillus cereus isolation, ribotyping and control in post-pasteurized milk / Isolamento, ribotipagem e controle de Bacillus cereus após a pasteurização do leite
Bacillus cereus recontamination of post-pasteurized milk was assessed by product analysis and by previously sanitized surfaces analysis. The milk samples were collected during nine weeks and the surfaces of the packaging machine screw (PMS); of the packaging machine leveling tank (PMLT); of the package forming tube (PFT); of the packaging tube (PT), and of t
Publicado em: 2007
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23. 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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24. Acionamento suave do motor de indução bifasico atraves de eletronica de potencia
This text introduces a new topology supply for the single-phase induction motor using power electronics. The proposed method does not use centrifugal switch and reduces starting current with a cheap circuitry. The analysis will be based on drive behavior, analyzing mechanical values, and as load behavior ? electrical values ? for a distribution network. Main
Publicado em: 2005