A Study on the Heat Flow Inside UPS according to the Outside Temperature -Dong – Min Kim Department of Mechanical Engineering, The Graduate School Konyang University Nonsan Chungnam Korea

Dong – Min Kim Department of Mechanical Engineering, The Graduate School Konyang University Nonsan Chungnam Korea

 UPS is an electrical apparatus that provides emergency power to a load when the input power source, typically mains power, fails. When installing UPS in outdoors (a road near or mountain, etc..), it is also possible many problems according to the outdoor environment. And it is possible generate condensation by a temperature difference The purpose of this study was to predict the inner temperature of UPS and to prevent dew condensation in UPS by simulating the heat flow using ANSYS. So in this study, The inner heat flow simulations for UPS were conducted by the Computation Fluid Dynamics Analysis, ANSYS, during the active state of UPS. Compared with Air temperature, Relative humidity, Inner temperature of UPS to be found that condensation is occurring. It’s can be improved by ventilation or insulation effectively inside UPS according to this simulation result.
LINK
http://www.mediafire.com/view/64sm02hh5f7f4ob/A_Study_on_the_Heat_Flow_Inside_UPS_according_to_the_Outside_Temperature.pdf

Short-circuit and selection of electrical equipment Kryuchkov - Короткие замыкания и выбор электрооборудования Крючков И.П.

Short-circuit and selection of electrical equipment Kryuchkov - Короткие замыкания и выбор электрооборудования Крючков И.П.
The methods for calculating short circuits, simple and complex asymmetrical modes in power systems, thermal and electrodynamic effects short circuit currents in the conductors and electrical equipment, methods and techniques for limiting short-circuit currents, especially the calculations of short circuits in the electrical voltage up to 1 kV.
LINK ORIGINAL EN LA WEB FORMATO DJVU
http://mexalib.com/download/35812

LINK ALTERNATIVO FORMATO PDF

A Novel Single-Phase Cascaded Multilevel AC-AC Converter Without Commutation Problem Kim, Sang-hun Department of Electrical Engineering Graduate School, Kyungpook National University Daegu, Korea

Abstract)
 This paper presents a novel cascaded multilevel PWM ac-ac converter that can solve commutation problem. By cascading the single-phase PWM ac-ac converter that uses basic switching cell structure and coupled inductors, the proposed converter does not need to sense the voltage or current polarity for safe commutation. When many unit-cells are cascaded, the proposed converter has more output voltage levels and can obtain high ac output voltage by using low voltage rating switching devices. By applying phase-shifted PWM technique, the proposed converter can reduce output filter size significantly. A 2 kW prototype converter having four unit-cell structure is built and tested to verify the performance. *

LINK
http://www.mediafire.com/view/8p898ucoid8uf3b/CONVERTER_AC-AC-2015.pdf

A VOLTAGE SAG SUPPORTER UTILIZING A PWM-SWITCHED AUTOTRANSFORMER A Thesis Presented to The Academic Faculty by Dong-Myung Lee School of Electrical & Computer Engineering Georgia Institute of Technology Atlanta

INTRODUCTION
1.1 Background A power distribution system is similar to a vast network of rivers. It is important to remove any system faults so that the rest of the power distribution service is not interrupted or damaged. When a fault occurs somewhere in a power distribution system, the voltage is affected throughout the power system. Among various power quality problems, the majority of events are associated with either a voltage sag or a voltage swell, and they often cause serious power interruptions. A voltage sag condition implies that the voltage on one or more phases drops below the specified tolerance for a short period of time. A voltage swell condition occurs when the voltage of one or more phases rises above the specified tolerance for a short period of time. The causes of voltage sags and swells are associated with faults within the power distribution system. Users located a close distance to the fault experience voltage sags much greater in magnitude and duration than users located farther away, and as the power distribution system have power interruptions during a fault because of the effects of a voltage sag or voltage swell produced in the system by the fault. The objective of this research is to develop a novel voltage control scheme that can compensate for voltage sag and swell conditions in three-phase power systems.

LINK
ttp://www.mediafire.com/view/j1wv1l6fu2p57fb/ESTABILIZADOR_AC-KOREA-2015.pdf

Análise de Circuitos Elétricos - Paulo Antonio Mariotto

LINK ORIGINAL EN LA WEB
http://dichavados.blogspot.com.br/2012/01/analise-de-circuitos-eletricos-paulo.html
LINK DIRECTO
https://mega.co.nz/#!cEkWkJrS!hmXVrCCchzl54uJNHnFeBA8CVc01f7uW0QxFYYWj-j0