“SE SEUS PROJETOS FOREM PARA UM ANO,SEMEIE O GRÂO.SE FOREM PARA DEZ ANOS,PLANTE UMA ÁRVORE.SE FOREM PARA CEM ANOS,EDUQUE O POVO.”

“Sixty years ago I knew everything; now I know nothing; education is a progressive discovery of our own ignorance. Will Durant”

OBRIGADO DEUS PELA VIDA,PROTEGENOS E GUARDANOS DE TODO MAL


AUTOR DO BLOG ENG. ARMANDO CAVERO MIRANDA SAO PAULO BRASIL

sexta-feira, 28 de outubro de 2016

ARC FLASH HAZARDS ANALYSIS by ZHENYUAN ZHANG Graduate School of The University of Texas at Arlington 2015


ARC FLASH HAZARDS ANALYSIS by ZHENYUAN ZHANG

Presented to the Faculty of the Graduate School of The University of Texas at Arlington in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY THE UNIVERSITY OF TEXAS AT ARLINGTON


Abstract 

ARC FLASH HAZARDS ANALYSIS Zhenyuan Zhang, PhD The University of Texas at Arlington, 2015
 Supervising Professor: Wei-Jen Lee

 Annually more than 2000 workers are admitted to hospital burn centers for extensive injuries caused by arc flash accidents. Arc flash incidents occur when unintended electric current flows through air, superheating the air and causes an explosion. Recognizing the significant threat posed by arc flash hazards, IEEE and NFPA have joined forces on an initiative to support research and additional testing to increase the understanding of the arc flash phenomena. Accurately represent all the real applications for arc flash events are very difficult, not only because of their random complex nature, but also because a large number of uncertain variables involved. Several areas of the arc flash phenomena need further research and testing validation. In order to have a precise arc flash hazards assessment, approximately 2000 arc flash experiments had been conducted, which are crossed extensive range of system voltage, bolted fault current, electrodes gap width, arc initiative configuration and enclosure dimensions. This dissertation has reviewed the testing methodology, test equipment design and modeling process for arc flash hazards analysis. The research and testing focused on, but will not be limited to (a) the development of physics and engineering-based modeling for arc flash thermal hazards, and (b) design and testing for non-thermal hazards, such as light, pressure and sound. Based on the works of the dissertation, sets of assessment equations and approaches have been proposed for arc flash thermal and non-thermal hazard analysis. The results of this dissertation will provide information to help more accurately predict the hazards associated with high energy arcing faults, thereby improving electrical safety standards and providing practical safeguards for employees in the work place.

LINK ORIGINAL
https://uta-ir.tdl.org/uta-ir/bitstream/handle/10106/25513/ZHANG-DISSERTATION-2015.pdf?sequence=1
LINK ALTERNATIVO
http://www.mediafire.com/file/2wbqqd7064st7ei/ZHANG-DISSERTATION-2015.pdf

quinta-feira, 27 de outubro de 2016

High-Performance Control of Three-Phase Four- Wire DVR Systems using Feedback Linearization Seon-Yeong Jeong*, Thanh Hai Nguyen**, Quoc Anh Le**, and Dong-Choon Lee†


High-Performance Control of Three-Phase Four- Wire DVR Systems using Feedback Linearization Seon-Yeong Jeong*, Thanh Hai Nguyen**, Quoc Anh Le**, and Dong-Choon Lee† *Department of Research and Development, T.E.C.C. Co. Ltd., Daegu, Korea **,†Department of Electrical Engineering, Yeungnam University, Gyeongsan, Korea 
Abstract
Power quality is a critical issue in distribution systems, where a dynamic voltage restorer (DVR) is commonly used to mitigate the voltage disturbances for loads. This paper deals with a nonlinear control for the three-phase four-wire (3P-4W) DVR under a grid voltage unbalance and nonlinear loads in the distribution system, where a novel control scheme based on the feedback linearization technique is proposed. Through feedback linearization, a nonlinear model of a DVR with a PWM voltage-source inverter (VSI) and LC filters is linearized. Then, the controller design of the linearized model is performed by applying the linear control theory, where the load voltages are kept constant by controlling the d-q-0 axis components of the DVR output voltages. To keep the load voltage unchanged, an in-phase compensation strategy is employed, where the load voltages are recovered to be the same as the previous voltage without a change in the magnitude. With this strategy, the performance of the DVR becomes faster and more stable even under unbalanced source voltages and nonlinear loads. The validity of the proposed control strategy has been verified by simulation and experimental results.

Key words: Dynamic voltage restorers, feedback linearization, SOGI-PLL, three-phase four-wire VSI, voltage unbalance

 LINK: http://ocean.kisti.re.kr/downfile/volume/kipe/E1PWAX/2016/v16n1/E1PWAX_2016_v16n1_351.pdf

quarta-feira, 26 de outubro de 2016

Power Modules for Combining Innovation, Flexibility and Power Capability in the Various 3-Level Topologies - By Narender Lakshmanan and Thomas Radke, Mitsubishi Electric Europe



Three level topologies have demonstrated higher efficiencies, filter optimization potential and the capability of handling high DC-link voltages. To maximize the advantages offered by the 3-level topologies, Mitsubishi Electric offers new power modules which unlock the potential to realize innovative solutions for different power segments. By Narender Lakshmanan and Thomas Radke, Mitsubishi Electric Europe B.V. and Satoshi Kawabata, Mitsubishi Electric Corporation Japan Power Device Works.
 LINK ORIGINAL EN LA WEB
https://www.hy-line.de/fileadmin/Public/Power/hersteller/mitsubishi/dokumente/BPs_04-16_Mitsubishi.pdf

quinta-feira, 20 de outubro de 2016

KOLFF en ExpoPreve Duoc San Joaquín


KOLFF nuevamente se hace presente en el evento Expo Preve 2016 de Duoc UC. En esta oportunidad la actividad se realizó en la sede San Joaquín del Instituto, en la cual se hizo presente gran cantidad de expertos en Seguridad, junto a cientos de alumnos de las carreras de Ingeniería y Técnico en Prevención de Riesgos. Como empresa nos sentimos orgullosos de apoyar la formación de estos jóvenes que se integrarán prontamente a la Industria nacional.
 FUENTE ORIGINAL DE LA NOTICIA
http://kolff-e.com/2016/10/07/kolff-en-expopreve-duoc-san-joaquin/

quarta-feira, 19 de outubro de 2016

BIRNS Emergency Light Fixture-LED Seismic Testing



This video shows BIRNS Emergency Light Fixture-LEDs (ELF-LEDs) during IEEE-344 seismic qualification testing at the National Technical Systems facility. This demanding test sequence uses a tri-axial acceleration table delivering the equivalent of a seismic event at 10Gs of force in the x, y and z axes.

BIRNS ELF-LEDs are advanced, seismically qualified nuclear grade lighting systems that provide 24-40 hours of standby illumination in the event of loss of AC power, which is 3 to 5 times longer than required by the NRC. These rugged, CE marked, RoHS compliant systems have a lamp life of 50,000 hours, and an 11 W power draw.

quarta-feira, 12 de outubro de 2016

Beginning arduino 2nd edition sep 2013


LINK ORIGINAL EN LA WEB
https://issuu.com/putrajambak/docs/apress.beginning.arduino.2nd.editio

Arduino workshop a hands on introduction with 65 projects


LINK ORIGINAL EN LA WEB
https://issuu.com/issuuk/docs/arduino_workshop_a_hands-on_introdu

Simulación de circuitos electróncos con PSpice Juan Aguilar


LINK ORIGINAL
https://issuu.com/jaguilarpena/docs/seminario

LINK ALTERNATIVO DIRECTO
http://www.mediafire.com/file/uk2kboxden1kn3o/Seminario.pdf

Transistor Circuit Techniques - 3rd Edition - G. J. Ritchie


LINK ORIGINAL EN LA WEB
https://issuu.com/robertocteixeira/docs/transistor_circuit_techniques_-_3rd

Digital Control in Power Electronics - Paolo Mattavelli AND Simone Buso


LINK ORIGINAL EN LA WEB
https://issuu.com/robertocteixeira/docs/digital_control_in_power_electronic

COMPLETE DIGITAL DESIGN- MARK BALCH


LINK ORIGINAL EN LA WEB
https://issuu.com/mohummadabdullah/docs/complete-digital-design

terça-feira, 11 de outubro de 2016

ENERGIA SOLAR COM BATERIAS (OFF-GRID)


O segundo de uma série de vídeos, que tratará da geração de energia solar, através de sistemas fotovoltaicos isolados , autônomos à bateria. Saiba quanto custa este tipo de solução, o retorno do investimento e as oportunidades de negócio no Brasil.

Geração de energia fotovoltaica conectada à rede elétrica



Parceria entre Núcleo de Pesquisa em Eletrônica de Potência (NUPEP) e as empresas ECONOVA Sistemas de Energia, PGM Sistemas e CEMIG D propiciará o desenvolvimento de uma pioneira Dissertação de Mestrado sobre Projeto Piloto de um Sistema Fotovoltaico Comercial Conectado à Rede

segunda-feira, 10 de outubro de 2016

Charging Nickel-cadmium -BATTERY UNIVERSITY


Figure 1: Charge characteristics of a NiCd cell. Charge efficiency is high up to 70% SoC and then charge acceptances drops. NiMH is similar to NiCd. Charge efficiency measures the battery’s ability to accept charge and has similarities with coulombic efficiency.

Learn how to maximize charge, minimize heat and reduce memory.

 Battery manufacturers recommend that new batteries be slow-charged for 16–24 hours before use. A slow charge brings all cells in a battery pack to an equal charge level. This is important because each cell within the nickel-cadmium battery may have self-discharged at its own rate. Furthermore, during long storage the electrolyte tends to gravitate to the bottom of the cell and the initial slow charge helps in the redistribution to eliminate dry spots on the separator. (See also BU-803a: Loss of Electrolyte.)
Battery manufacturers do not fully format nickel- and lead-based batteries before shipment. The cells reach optimal performance after priming that involves several charge/discharge cycles. This is part of normal use; it can also be done with a battery analyzer. Quality cells are known to perform to full specifications after only 5–7 cycles; others may take 50–100 cycles. Peak capacity occurs between 100–300 cycles, after which the performance starts to drop gradually.
 Most rechargeable cells include a safety vent that releases excess pressure if incorrectly charged. The vent on a NiCd cell opens at 1,000–1,400kPa (150–200psi). Pressure released through a re-sealable vent causes no damage; however, with each venting event some electrolyte escapes and the seal may begin to leak. The formation of a white powder at the vent opening makes this visible. Multiple venting eventually results in a dry-out condition. A battery should never be stressed to the point of venting.
 Full-charge Detection by Temperature 
 Full-charge detection of sealed nickel-based batteries is more complex than that of lead acid and lithium-ion. Low-cost chargers often use temperature sensing to end the fast charge, but this can be inaccurate. The core of a cell is several degrees warmer than the skin where the temperature is measured, and the delay that occurs causes over-charge. Charger manufacturers use 50°C (122°F) as temperature cut-off. Although any prolonged temperature above 45°C (113°F) is harmful to the battery, a brief overshoot is acceptable as long as the battery temperature drops quickly when the “ready” light appears.
 Advanced chargers no longer rely on a fixed temperature threshold but sense the rate of temperature increase over time, also known as delta temperature over delta time, or dT/dt. Rather than waiting for an absolute temperature to occur, dT/dt uses the rapid temperature increase towards the end of charge to trigger the “ready” light. The delta temperature method keeps the battery cooler than a fixed temperature cut-off, but the cells need to charge reasonably fast to trigger the temperature rise. Charge termination occurs when the temperature rises 1°C (1.8°F) per minute. If the battery cannot achieve the needed temperature rise, an absolute temperature cut-off set to 60°C (140°F) terminates the charge.

 Chargers relying on temperature inflict harmful overcharges when a fully charged battery is repeatedly removed and reinserted. This is the case with chargers in vehicles and desktop stations where a two-way radio is being detached with each use. Reconnection initiates a new charge cycle that requires reheating of the battery.
Li ion systems have an advantage in that voltage governs state-of-charge. Reinserting a fully charged Li-ion battery immediately pushes the voltage to the full-charge threshold, the current drops and the charger turns off shortly without needing to create a temperature signature.
 Full-charge Detection by Voltage Signature
 Advanced chargers terminate charge when a defined voltage signature occurs. This provides a more precise full-charge detection of nickel-based batteries than temperature-based methods. The charger looks for a voltage drop that occurs when the battery has reached full charge. This method is callednegative delta V (NDV).
 NDV is the recommended full-charge detection method for chargers applying a charge rate of 0.3C and higher. It offers a quick response time and works well with a partially or fully charged battery. When inserting a fully charged battery, the terminal voltage rises quickly and then drops sharply to trigger the ready state. The charge lasts only a few minutes and the cells remain cool. NiCd chargers with NDV detection typically respond to a voltage drop of 5mV per cell.
 To achieve a reliable voltage signature, the charge rate must be 0.5C and higher. Slower charging produces a less defined voltage drop, especially if the cells are mismatched in which case each cell reaches full charge at a different time point. To assure reliable full-charge detection, most NDV chargers also use a voltage plateau detector that terminates the charge when the voltage remains in a steady state for a given time. These chargers also include delta temperature, absolute temperature and a time-out timer.
 Fast charging improves the charge efficiency. At 1C charge rate, the efficiency of a standard NiCd is 91 percent and the charge time is about an hour (66 minutes at 91 percent). On a slow charger, the efficiency drops to 71 percent, prolonging the charge time to about 14 hours at 0.1C.
During the first 70 percent of charge, the efficiency of a NiCd is close to 100 percent. The battery absorbs almost all energy and the pack remains cool. NiCd batteries designed for fast charging can be charged with currents that are several times the C-rating without extensive heat buildup. In fact, NiCd is the only battery that can be ultra-fast charged with minimal stress. Cells made for ultra-fast charging can be charged to 70 percent in minutes.
 Figure 1 shows the relationship of cell voltage, pressure and temperature of a charging NiCd. Everything goes well up to about 70 percent charge, when charge efficiency drops. The cells begin to generate gases, the pressure rises and the temperature increases rapidly. To reduce battery stress, some chargers lower the charge rate past the 70 percent mark. Charge characteristics of a NiCd cell Figure 1: Charge characteristics of a NiCd cell. Charge efficiency is high up to 70% SoC and then charge acceptances drops. NiMH is similar to NiCd. Charge efficiency measures the battery’s ability to accept charge and has similarities with coulombic efficiency.
LINK ORIGINAL
http://batteryuniversity.com/learn/article/charging_nickel_based_batteries

quinta-feira, 6 de outubro de 2016

Consultoria para certificação compulsória de produtos "Ex" - Portaria do INMETRO 179


A HLR Serviços atua com assessoria no processo de Certificação Compulsória de produtos seguindo a Portaria 179 INMETRO. Proporcionamos às empresas todo o suporte necessário na elaboração dos documentos, definição das marcações dos produtos, suporte para definição dos ensaios laboratoriais, escolha do Organismo de Certificação de produtos – OCP e na realização de auditorias internas seguido os critérios da Norma ABNT ISO/ IEC 80079-34 – SGQ para Fabricação de produtos para atmosferas explosivas. Ministramos também treinamentos sobre conceitos básicos e instalações de produtos para Áreas Classificadas – Gás e Poeiras combustíveis. Possui dúvidas? Precisa de suporte para certificar outros produtos que seguem regulamentação do INMETRO? Entre em contato e faça uma consulta. Consulte também outros serviços disponíveis em nosso site: www.hlrservicos.com.br Eng. Ricardo Zanata Auditor & Consultor Técnico Atmosferas Explosíveis e ISO9001 + 55 (11) 2355-1552 + 55 (11) 9 8145-8405 Skype: ricardo.zanata
 LINK ORIGINAL
https://www.linkedin.com/pulse/consultoria-para-certifica%C3%A7%C3%A3o-compuls%C3%B3ria-de-produtos-ricardo-zanata?trk=hp-feed-article-title-like

terça-feira, 4 de outubro de 2016

Techmultlab ENSAIOS para o tipo de proteção Ex “t”, de acordo com a norma ABNT NBR IEC 60079-31 - Atmosferas explosivas - Ensaios de grau de proteção contra ingresso de poeira (Códigos IP 5X e IP 6X)


Techmultlab Ensaios Ltda, de São Paulo (SP), obteve recentemente a acreditação para a execução de ensaios para o tipo de proteção Ex “t”, de acordo com a norma ABNT NBR IEC 60079-31 - Atmosferas explosivas - Parte 31: Proteção de equipamentos contra ignição de poeira por invólucros “t”. Segundo os especialistas do setor, trata-se da primeira acreditação do Inmetro conferida a um laboratório nacional de ensaios Ex para o tipo de proteção Ex “t”. Este tipo de proteção é destinado a equipamentos para instalação em áreas classificadas contendo poeiras combustíveis, dos tipos Zona 20, 21 ou 22. Entre os principais diferenciais do Techmultlab está sua capacidade de execução de ensaios de grau de proteção contra ingresso de poeira (Códigos IP 5X e IP 6X) em invólucros com grandes dimensões, pois a unidade dispõe de câmara de ensaio para poeira com capacidade até 2.700x1.650x1.650 mm. Estas dimensões permitem, em muitos casos, a realização de ensaios dos equipamentos Ex no seu tamanho real, sem a necessidade de recorrer a ensaios de modelos reduzidos.
Contato
55 11 2338-5608 comercial@techmultlab.com.br R. João Serrano, 104 - Bairro do Limão - São Paulo

segunda-feira, 3 de outubro de 2016

CONDICIONAMENTO DE ENERGIA PAPEL ESTRATÉGICO REVISTA POTENCIA



Crises econômica e energética exigem investimentos em soluções para aumentar a proteção de equipamentos destinados a promover a eficiência operacional das empresas. Com isso, nobreaks e estabilizadores ganham posição de destaque .

Com relação à segurança e desempenho de estabilizadores de tensão com potência até 3 kVA e tensão nominal até 250 V, existe a norma brasileira NBR 14373, publicada inicialmente em 1999 e revisada tecnicamente em 2006. É compulsória por determinação do Inmetro – Instituto Nacional de Metrologia, Qualidade e Tecnologia, responsável pela acreditação dos organismos certificadores, os quais devem fazer a fiscalização juntamente com o IPEM – Instituto de Pesos e Medidas.

“Quanto aos estabilizadores de tensão, considera-se que o mercado está bem organizado e sob constante vigilância”, afirma Adriana Nobre, da Schneider Electric. Em relação aos nobreaks monofásicos com potência até 3 kVA e tensão nominal até 250 V, existe a NBR 15204, porém, ela não se tornou compulsória até hoje. Vale ressaltar que, em muitos projetos corporativos, que envolvem nobreaks, as empresas exigem o cumprimento de normas internacionais como IEC e UL. 

Como consequência da falta de regulamentação e fiscalização adequada, existem empresas que oferecem produtos de baixa qualidade com preços abaixo do de mercado. “Nobreaks e estabilizadores sem qualidade, além de não cumprirem sua função de proteger os equipamentos eletrônicos a ele ligados, podem, ainda, causar danos a esses equipamentos, deixando passar energia de má qualidade, que ocasiona, ao longo do tempo, desgaste dos componentes internos, chegando até a queima do equipamento a médio e longo prazo”, adverte Gisella Magne, da SMS.

 Outra dificuldade enfrentada pelo setor é a carga tributária incidente sobre esses equipamentos, equivalente a 37% do valor de venda, o que dá abertura para a entrada dos produtos asiáticos, muitas vezes de qualidade duvidosa. A variação cambial (por conta da importação dos componentes) e os preços das commodities (cobre) são outros desafios impostos ao crescimento desse mercado. “Além disso, o dimensionamento e a especificação dos produtos corretos para suas respectivas aplicações são outras questões importantes, que podem levar à subutilização ou à sobrecarga dos estabilizadores e nobreaks”, alerta Adriana Nobre.


As perspectivas para este mercado são otimistas, considerando os investimentos crescentes na terceira plataforma, isto é, cloud computing, aplicações de mobilidade, big data, analytics e redes sociais. Adriana Nobre | Schneider Electric

LEIA O ARTIGO COMPLETO NO WEBSITE ORIGINAL
http://www.abilux.com.br/portal/pdf/midia/SiteAbilux_Potencia-23-11-2015.pdf

REVISTA POTENCIA-LABORATORIOS DE TESTES E ENSAIOS DE PRODUTOS PARA ÁREA ELÉTRICA NO BRASIL ENG. HILTON MORENO










PODES LER O ARTIGO COMPLETO E BAIXAR A REVISTA POTENCIA NO WEBSITE ORIGINAL:
http://www.abilux.com.br/portal/pdf/midia/SiteAbilux_Potencia-23-11-2015.pdf