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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

An?lise de falhas em rolamentos por an?lise de vibra??o aplicado a aerogeradores / Failure analysis on bearing vibration analysis applied to wind turbines

Almeida, Isac Barbosa de 06 May 2016 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-08-16T20:26:43Z No. of bitstreams: 1 IsacBarbosaDeAlmeida_DISSERT.pdf: 2821753 bytes, checksum: df59d2e78eb7f99cfa9a96085f3eae4c (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-08-18T21:53:45Z (GMT) No. of bitstreams: 1 IsacBarbosaDeAlmeida_DISSERT.pdf: 2821753 bytes, checksum: df59d2e78eb7f99cfa9a96085f3eae4c (MD5) / Made available in DSpace on 2016-08-18T21:53:45Z (GMT). No. of bitstreams: 1 IsacBarbosaDeAlmeida_DISSERT.pdf: 2821753 bytes, checksum: df59d2e78eb7f99cfa9a96085f3eae4c (MD5) Previous issue date: 2016-05-06 / Com a intensa utiliza??o de rolamentos em diversos segmentos da ind?stria, h? um elevado n?mero de pausas necess?rias nos processos industriais para a realiza??o de manuten??es nesses dispositivos, tendo como estudo de caso os aerogeradores. O crescimento do setor de energia e?lica, incentivou a realizar uma pesquisa que auxilie a solu??o desse problema. Para contribuir com a manuten??o preventiva foi realizado uma an?lise de sinais aplicando t?cnicas que permitem a detec??o e a localiza??o do problema a fim de evitar acidentes e preju?zos ocasionados por falhas inesperadas nos equipamentos, visto que a baixa rota??o do sistema dificulta a detec??o da falha. Para solucionar esse item, realizou-se a determina??o de sinais padr?o para os defeitos nos rolamentos, facilitando o diagn?stico de poss?veis falhas. Com esse diagn?stico pode ser executada uma manuten??o preventiva, identificando a falha do sistema que foram testadas, como a introdu??o de gr?os de areia no rolamento, desgaste na pista externa do rolamento e oxida??o do rolamento. Atrav?s do processamento de sinais ? poss?vel construir os gr?ficos desenvolvendo um mapeamento dos defeitos atrav?s de diferentes picos nas faias de frequ?ncia. / With the heavy use of bearings in various segments of the industry, there are a large number of necessary interruptions in industrial processes to perform maintenance on these devices, with the case study wind turbines. The growth of the wind energy sector, encouraged to conduct research that helps to solve this problem. To contribute to predictive maintenance has been carried out a signal analysis using techniques which allow detection and location of the problem in order to prevent accidents caused and losses due to unexpected equipment failures, whereas low system rotation complicates the detection of the failure. To work around this problem, there was the indication of standard signals for defects in the bearings, making diagnosis of possible failures. With this diagnosis can be performed predictive maintenance, identifying the failure of the system that were tested, such as the introduction of grains of sand in the bearing, wear on the outer race of the bearing and bearing rust. By processing signals it is possible to construct graphs developing a mapping of defects by different peaks in the frequency band.
2

An?lise preditiva a partir da caracteriza??o das emiss?es gasosas e do ?leo lubrificante em frotas com motoriza??o a diesel

Sousa, Eduardo Henrique Viana de 30 August 2010 (has links)
Made available in DSpace on 2014-12-17T14:58:03Z (GMT). No. of bitstreams: 1 EduardoHVS_DISSERT.pdf: 4888448 bytes, checksum: 16ede4f993cb59d4e084c847af90483e (MD5) Previous issue date: 2010-08-30 / This work was motivated by the importance of conducting a study of vehicle emissions in captive fleets with diesel engine, coupled with the predictive maintenance plan. This type of maintenance includes techniques designed to meet the growing market demand to reduce maintenance costs by increasing the reliability of diagnoses, which has increased interest in automated predictive maintenance on diesel engines, preventing problems that might evolve into routine turn into serious situations, solved only with complex and costly repairs, the Reliability Centered Maintenance, will be the methodology that will make our goal is reached, beyond maintaining the vehicles regulated as fuel consumption and emissions. To Therefore, technical improvements were estimated capable of penetrating the automotive market and give the inshore fleet emission rates of opacity of the vehicles, being directly related to the conditions of the lubricating oil thus contributing to reducing maintenance costs by contributing significantly to emissions of pollutants and an improvement in the air in large cities. This criterion was adopted and implemented, em 241 buses and produced a diagnosis of possible failures by the correlation between the characterization of used lubricating oils and the analysis of opacity, with the objective of the aid the detection and solution of failures for the maintenance of sub-systems according to design criteria, and for this to be a deductive methodology to determine potential causes of failures, has been automated to implement a predictive maintenance system for this purpose was used in our study a mobile unit equipped with a opacimeter and a kit for collection and analysis of lubricating oil and the construction of the network diagnostics, we used a computer program in Microsoft Office Access 2007 platform tool is indispensable for creating a database data, this method is being used and successfully implemented in seven (7) bus companies from the city of Natal (RN) Brazil / Este trabalho foi motivado pela import?ncia de realizar um estudo das emiss?es veiculares em frotas cativas com motoriza??o a diesel, associado ao plano de manuten??o preditiva. Esta modalidade de manuten??o engloba t?cnicas destinadas a atender a crescente exig?ncia do mercado em reduzir custos de manuten??o pelo aumento da confiabilidade dos diagn?sticos, o que fez crescer o interesse pelos sistemas automatizados de manuten??o preditiva nos motores a diesel, impedindo que problemas de rotina possam evoluir at? se transformarem em situa??es graves, solucion?veis apenas com repara??es complexas e dispendiosas, esta Manuten??o Centrada em Confiabilidade, ser? a metodologia que far? com que o objetivo seja atingido; al?m de manter os ve?culos regulados quanto ao consumo de combust?vel e emiss?o de poluentes. Para isso, estimaram-se melhorias t?cnicas capazes de penetrar no mercado automotivo e de conferir, nas frotas cativas, os ?ndices de emiss?o de opacidade dos ve?culos, sendo isso relacionado diretamente ?s condi??es do ?leo lubrificante, possibilitando a redu??o de custos de manuten??o, contribuindo de forma consider?vel com as emiss?es de poluentes e uma melhoria no ar das grandes metr?poles. Esse crit?rio foi adotado e implementado, em 241 ?nibus sendo produzido um diagn?stico das poss?veis falhas atrav?s da correla??o entre a caracteriza??o dos ?leos lubrificantes usados e a an?lise de opacidade, tendo como objetivo o aux?lio na detec??o e solu??o de falhas, visando ? manuten??o dos subsistemas segundo os crit?rios de projeto. Por ser esta uma metodologia dedutiva na determina??o de potenciais causas de falhas, foi automatizada para a implementa??o de um sistema de manuten??o preditiva; para esse fim foi utilizado nesse estudo uma unidade m?vel equipada com um opac?metro e um kit para coleta e analise do ?leo lubrificante; para a constru??o da rede de diagn?sticos foi utilizado um programa de computador em plataforma Microsoft Office Access 2007, ferramenta fundamental para a cria??o de um banco de dados, este m?todo est? sendo utilizado e implementado com sucesso nas sete empresas de ?nibus urbanos da cidade do Natal/RN, Brasil
3

Sistema embarcado para monitoramento de circuitos auxiliares em disjuntores de pot?ncia de distribuidoras de energia el?trica

Cavalcante, S?rgio Gomes 28 July 2017 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-11-06T21:17:06Z No. of bitstreams: 1 SergioGomesCavalcante_DISSERT.pdf: 2152523 bytes, checksum: 2c09534044f4a7214627c3d49f0aaa8e (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-11-20T23:59:14Z (GMT) No. of bitstreams: 1 SergioGomesCavalcante_DISSERT.pdf: 2152523 bytes, checksum: 2c09534044f4a7214627c3d49f0aaa8e (MD5) / Made available in DSpace on 2017-11-20T23:59:14Z (GMT). No. of bitstreams: 1 SergioGomesCavalcante_DISSERT.pdf: 2152523 bytes, checksum: 2c09534044f4a7214627c3d49f0aaa8e (MD5) Previous issue date: 2017-07-28 / O modelo de sistema el?trico introduzido no Brasil no final da d?cada de 90 produziu um ambiente com alto grau de regula??o. A cria??o da Ag?ncia Nacional de Energia El?trica (ANEEL) e suas regras for?am os agentes envolvidos nesse sistema a sempre procurarem a modicidade tarif?ria com um n?vel elevado de qualidade do servi?o e qualidade do produto. Estas exig?ncias impostas ?s concession?rias de energia no Brasil fazem com que as empresas desenvolvam processos para uma melhoria constante, mas nem sempre essas estrat?gias s?o suficientes para garantir bons indicadores de qualidade. Por vezes o processo n?o mant?m uma sincronia ideal a ponto de evitar falhas em sua execu??o. Outras vezes, as falhas n?o est?o nos processos em si, mas nos pr?prios equipamentos. Como exemplo, podem ser citadas as programa??es de manuten??o preventiva que s?o desenvolvidas em alguns equipamentos de uma subesta??o. Ainda podem ser citadas, as falhas intempestivas que para serem corrigidas ? necess?rio que a informa??o correta, percorra os canais de comunica??o de forma r?pida e precisa chegando at? aos respons?veis pela manuten??o. Nem sempre as informa??es certas chegam aos setores respons?veis com rapidez e precis?o, somado a isso, estas informa??es n?o s?o armazenadas e catalogadas para analises futuras. O presente projeto tem como objetivo fundamental dotar os disjuntores, equipamentos do sistema de prote??o, de intelig?ncia, por meio de um sistema embarcado. Com esta associa??o, os disjuntores ser?o capazes de desempenhar suas funcionalidades com rapidez e assertividade nos dados gerados, podendo antecipar-se ?s falhas tornando o sistema el?trico mais confi?vel e seguro. / The Electric Power System model introduced in Brazil in the late 1990s produced a scenario with a high regulation level. The Ag?ncia Nacional de Energia El?trica (ANEEL) creation and its rules force the agents involved in that system to always seek the low tariffs with a high quality level of service and product quality. The requirements imposed on Brazilian Power Utilities result in the development of processes that allow a continuous improvement. Nevertheless, these strategies are not always sufficient to ensure good quality indicators. Many times, the processes do not hold a perfect synchrony to the point of avoiding execution failures. Other times, the failures are not in the processes, but in the equipment that are objective of the existence of the processes. As an example the preventive maintenance schedules that are developed in certain equipment of a Substation. Another example, unscheduled failures to be corrected is necessary that the correct information, scroll through the channels of communication to quickly and accurately reaching those responsible for maintenance. Correct information does not always reach the department quickly and accurately, but it is stored and cataloged for future analysis. This work aimed to reduce the DEC (Equivalent Duration of Interruption per Consumer Unit) indicator, improvement in maintenance planning and increase in the electrical installations? s safety level in a substation. By building an embedded system designed to monitor the main internal components of a circuit breaker. With the results achieved, it is concluded that the device provided in the project meets the objectives imposed, being able to perform its functions with speed and assertiveness in the data generated. The integration of this equipment into the circuit-breakers will allow anticipating the failures making the electrical system more reliable and safe.
4

Simula??o do sistema de esgotamento sanit?rio de Ponta Negra- Natal: mitiga??o dos riscos ambientais e estrat?gia de manuten??o preditiva

Lima, Fabiana Pereira de 31 August 2012 (has links)
Made available in DSpace on 2014-12-17T15:03:31Z (GMT). No. of bitstreams: 1 FabianaPLM_DISSERT.pdf: 3435369 bytes, checksum: eeb98ff1cae8e980fe5be54da04a6770 (MD5) Previous issue date: 2012-08-31 / The simulation of SES-Natal Ponta Negra: mitigation of environmental risks and predictive maintenance strategy was developed in the context of several operational irregularities in the pumping stations and sewage systems in the system Ponta Negra. Thus, the environmental risks and complaints against the company due to overflows of sewage into the public thoroughfare became common. This neighborhood has shown in recent years an increase of resident higher than the initial expectation of growth. In this sense presumed the large population growth and generation of sewers higher than expected, associated to the use of corrective maintenance and misuse of the system may be the main causes of operational failures occurring in the SES. This study aimed at analyzing the hydraulic behavior of SES Ponta Negrathrough numerical simulation of its operation associated to future scenarios of occupation. The SES Ponta Negra has a long lengthof collection networks and 6 pumping stations interconnected, being EE 1, 2, 4 coastal way, and beach Shopping interconnected EE3 to receives all sewers pumped from the rest pumping station and pumped to the sewage treatment station of neighborhood which consists of a facultative pond followed by three maturation ponds with disposal of treated effluent into infiltration ditches. Oncethey are connected with each other, the study was conducted considering the days and times of higher inflow for all lifts. Furthermore, with the aim of measuring the gatherer network failures were conducted data survey of on the networks. Thephysical and operational survey data was conducted between January/2011 and janeiro/2012. The simulation of the SES was developed with the aim ofdemonstrating its functioning, eithercurrently and in the coming years, based in population estimates and sewage flow. The collected data represents the current framework of the pumping stations of the SES Ponta Negra and served as input to the model developed in MS Excel ? spreadsheet which allowed simulating the behavior of SES in future scenarios. The results of this study show thatBeach Shopping Pumping Station is actually undersized and presents serious functioning problemsthatmay compromise the environmental quality of surrounding area. The other pumping stations of the system will reach itsmaximum capacity between 2013 and 2015, although the EE1 and EE3 demonstrateoperation capacity, even precariously, until 2017. Moreover, it was observed that the misuse of the network system, due to the input of both garbage and stormwater, are major factors of failures that occur in the SES. Finally, it was found that the corrective maintenance appliance, rather than predictive,has proven to beinefficient because of the serious failuresin the system, causing damage to the environment and health risks to users / A Simula??o do SES Ponta Negra- Natal: mitiga??o dos riscos ambientais e estrat?gia de manuten??o preditiva foi desenvolvida no contexto de diversas irregularidades operacionais nas esta??es elevat?rias e redes coletoras de esgoto no sistema de Ponta Negra. Com isso, os riscos ambientais e as denuncias contra a empresa de saneamento devido aos extravasamentos de esgotos em via p?blica se tornaram comuns. Esse bairro vem apresentando nos ?ltimos anos um aumento populacional muito maior do que a expectativa inicial de crescimento. Nesse sentido, sup?e-se o grande crescimento populacional e de gera??o de esgotos acima do esperado, atrelado ? utiliza??o de manuten??o corretiva e o mau uso do sistema podem ser as principais causas das falhas operacionais ocorridas neste SES. Esse estudo teve por objetivo analisar o comportamento hidr?ulico do SES de Ponta Negra a partir da simula??o num?rica do seu funcionamento associados ? cen?rios futuros de ocupa??o. O SES Ponta Negra apresenta quil?metros de redes coletoras e 6 esta??es elevat?rias interligadas, sendo a EE 1, 2, 4, Via Costeira e Praia Shopping interligadas a EE3, qual recebe todos os efluentes das demais elevat?rias e bombeia para a esta??o de tratamento de esgotos do bairro a qual ? constitu?da de uma lagoa facultativa seguida de 3 lagoas de matura??o com disposi??o dos efluentes tratados em valas de infiltra??o. Por serem interligadas entre si, o estudo foi realizado considerando os dias e horas de maior vaz?o afluente para todas as elevat?rias. Al?m disso, a fim de mensurar as falhas nas redes coletoras foram realizados levantamento dos dados de obstru??es nessas redes. O levantamento e coleta de dados f?sicos e operacionais foram realizados entre janeiro/2011 e janeiro/2012. A simula??o do SES foi desenvolvida, a fim de nos mostrar como esse est? funcionando atualmente, e como ir? funcionar nos pr?ximos anos, com base na estimativa populacional e de vaz?o de esgotos. Os dados coletados representam o quadro atual das esta??es elevat?rias do SES Ponta Negra e alimentaram o modelo num?rico desenvolvido em planilha eletr?nica MS Excel? que permitiu simular o comportamento do SES em cen?rios futuros. Os resultados obtidos neste estudo mostram que a elevat?ria Praia Shopping j? est? subdimensionada e apresenta falhas graves de funcionamento que compromete a qualidade do ambiente os aspectos ambientais da ?rea onde est? inserida. As demais elevat?rias do sistema atingir?o sua capacidade m?xima segura de bombeamento entre os anos de 2013 e 2015, embora a EE 1 e EE 3 tenham a capacidade de operar, ainda que de forma muito prec?ria, at? o ano de 2017. Al?m disso, observou-se que o mau uso do sistema, com a entrada de lixo e ?gua de chuva na rede coletora, s?o fatores determinantes para as falhas que ocorrem no SES. E finalmente, constatou-se que a utiliza??o de manuten??o corretiva, em vez da preditiva, no sistema como um todo tem se mostrado altamente ineficiente causando graves falhas no sistema, gerando com isso danos ao meio ambiente e riscos sanit?rios aos clientes
5

Desenvolvimento de um aplicativo para gerenciamento da manuten??o do sistema el?trico de pot?ncia da UFRN, utilizando o c?digo QR como ferramenta de acesso ao plano de manuten??o

Silva, Marcos Antonio Alves da 11 August 2017 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-12-04T22:25:53Z No. of bitstreams: 1 MarcosAntonioAlvesDaSilva_DISSERT.pdf: 2392478 bytes, checksum: fa9756e6692ee8e2b641c717a24729c2 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-12-11T21:16:38Z (GMT) No. of bitstreams: 1 MarcosAntonioAlvesDaSilva_DISSERT.pdf: 2392478 bytes, checksum: fa9756e6692ee8e2b641c717a24729c2 (MD5) / Made available in DSpace on 2017-12-11T21:16:38Z (GMT). No. of bitstreams: 1 MarcosAntonioAlvesDaSilva_DISSERT.pdf: 2392478 bytes, checksum: fa9756e6692ee8e2b641c717a24729c2 (MD5) Previous issue date: 2017-08-11 / ? percept?vel que, h? algum tempo, a sociedade vem passando por um processo de organiza??o da informa??o em suas pr?ticas e procedimentos, proporcionando grandes avan?os para a comunica??o e o armazenamento de dados, despertando nas institui??es p?blicas e privadas a necessidade de adapta??o e aperfei?oamento cont?nuo no tratamento de seus processos. Nesse contexto, apresenta-se uma proposta para a estrutura??o de um plano de manuten??o de equipamentos el?tricos, voltada para a manuten??o preventiva, baseada no gerenciamento da informa??o de todos os equipamentos de um sistema de distribui??o de energia el?trica. Dessa forma, partindo da an?lise das t?cnicas mais modernas de gerenciamento da manuten??o el?trica, define-se uma que melhor se enquadre na realidade do sistema el?trico de pot?ncia da Universidade Federal do Rio Grande do Norte ? UFRN, construindo-se um estudo de caso atrav?s do desenvolvimento de um sistema de gerenciamento da manuten??o baseado no cadastro de todos os seus componentes, cujo conte?do re?na os aspectos de gera??o de relat?rio de inspe??o, manuten??o preventiva e corretiva e cadastro dos dados t?cnicos dos equipamentos el?tricos, constituindo um banco de dados estruturado em ACCESS acess?vel via c?digo QR nos locais de instala??o. / It is noticeable that, for some time, society has been undergoing a process of information organization in its practices and procedures, providing significant advances for communication and data storage, raising in the public and private institutions the awareness of the need for continuous adaptation and improvement as it concerns the treatment of their processes. Within this context, we introduce a proposal to draw up an electric maintenance plan on whose stakeholders enjoy a systematic approach focused on preventive maintenance, based on the management of information of all elements of the electrical energy system. Accordingly, starting from the analysis of the most modern techniques of electric maintenance management, we can define one that better fits the reality of the electric power system of the Federal University of Rio Grande do Norte ? UFRN, thereby drawing up a case study through the development of a management system based on the registration of all its elements, whose content gathers the aspects related to the generation of inspection reports, corrective and preventive maintenance, and registration of technical data on the electric equipment, building a database structured in ACCESS accessible by means of QR code in the places where the equipment will be installed.

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