112 resultados para Inversor de tensão trifásico
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The purpose of this paper is to examine the paratexts, mainly prefaces and notes, written by translators on writings of foreigners' travels in Brazil, with the purpose of evidencing which perspective guided their translations, if the perspective of the foreign author is adopted or if it is that of the domestic reader. The works examined were published by the Brazilian publishing house Companhia Editora Nacional in the Brasiliana Colllection. Most of the translators adopted a welcoming discourse to the author in their prefaces, but their prefaces, translations and notes reveal a certain tension between what they stated and what was effectively done, with moments of rupture in which the author's meanings are questioned and even denied. According to my analysis, this happens because the several forces acting on the translation, the author, the translator and the text to be translated, the languages involved, the reader are not working linearly, but in constant tension. As a result, different perspectives are adopted in different translations, but in the same translation there are moments in which the foreign pole is privileged and moments in which the domestic pole emerges.
Proposta de uma metodologia de rebobinamento para converter motor de indução trifásico em monofásico
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This paper proposes the conversion of a three-phase induction motor into single phase through rewinding its stator. It presents a methodology to calculate this rewinding process considering the constructive parameters of the, such as number of slots and number of poles, for instance. The operating principles of DC motors are highlighted to introduce the logic involved in the calculation of lap and wave windings. The construction of the stator three-phase induction motor generally uses the lap winding, which is also used in single phase to perform the conversion. The rewinding process is widely used for reconstruction of industrial and residential electric motors that have suffered damage or present flaws with use. Therefore, many three-phase electric motors that are discarded or disposed of could be recovered by the method described in this work for a purpose that contributes to energy efficiency or simply saving resources in single-phase uses
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Pós-graduação em Engenharia Elétrica - FEIS
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The industry generally has sought materials with high mechanical resistance, low density, thermal stability and corrosion resistance. In the aerospace industry, for example, the use of aluminum alloys, such as Al 2024-T351 and Al 7075-T7351, have become essential. However, the use of these materials often do not resulted in a satisfactory performance of the component, since the presence of cracks can cause total rupture of the component, even with a tension below the yield stress of the material, unexpectedly. In this work, these aluminum alloys were analyzed and samples were modeled by the finite element method. Moreover, in the models were applied two different types of cracks, central and edge crack, a vertical force was applied to result in a tension 70% of the yield stress of the material analyzed. Through stress asymptotic distribution in the region near the crack tip were calculated the values of the stress intensity factors for each crack length, after the stress intensity factors characterized were compared graphically with the values of fracture toughness found in the available literature
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Pós-graduação em Engenharia Elétrica - FEIS
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Pós-graduação em Ciência Animal - FMVA
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Pós-graduação em Engenharia Elétrica - FEIS
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The magazines destined to the adolescent public are many times searched as a resource of information about sexuality, body, relationships and adolescence. The Capricho magazine is a biweekly feminine magazine directed to teenagers. In this qualitative-descriptive study it was made the content analysis of the section about sex of 18 editions published in 2010 with the aim of identifying and discussing the predominant representations of sexuality. It was identified the predominance of negative representations, like relations between sexuality and fear, tension, shame and beauty imperatives. It can be detached that the feminine sexuality is not approached through its pleasant, positive and health aspects, but through negative representations that, instead of being discussed, are naturalized, put as normal and expected by the magazine’s discourse.
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Pós-graduação em Engenharia Elétrica - FEIS
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Pós-graduação em Engenharia Mecânica - FEB
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Pós-graduação em Engenharia Elétrica - FEIS
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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This paper shows the modeling and control of a single-phase full-bridge inverter with high-frequency transformer that may be used as part of a two-stage converter with transformerless DC-DC side or as a single-stage converter (simple DC-AC converter) for grid-connected PV applications. The inverter is modeled in order to obtain a small-signal transfer function used to design the P+Resonant current controller. A highfrequency step-up transformer results in reduced voltage switches and better efficiency compared with converters in which the transformer is used on the DC-DC side. Simulations and experimental results with a 200 W prototype are shown. 1