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Nutritional strategy of early amino acid administration in very low birth weight infants

  • Lee, Byong Sop
    • Clinical and Experimental Pediatrics
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    • v.58 no.3
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    • pp.77-83
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    • 2015
  • Relative to a fetus of the same gestational age, very low birth weight (VLBW) infants are more likely to be underfed and to undergo growth restriction during their early hospital stay. The current trend towards "early and aggressive" nutritional strategies in VLBW infants aims to overcome the early nutritional deficiency and thereby boost postnatal catch-up growth, simultaneously improving long-term neurodevelopmental outcomes. Although the minimum starting amino acid (AA) dose to prevent negative nitrogen balance is well established, the upper limit and the rate of increase of early AA doses are controversial. Most randomized controlled trials show that early and high-dose (target, 3.5 to 4.9 g/kg/day) AA regimens, with or without high nonprotein calories, do not improve long-term growth and neurodevelopment. High-dose AA supplementation may lead to early metabolic disturbances and excessive or disproportionate plasma AA levels, particularly in infants of very low gestational age. Further large studies are needed to clarify the optimal strategy for early administration of parenteral AA doses in VLBW infants.

Modeling and Simulation of an SRM Drive (SRM구동을 위한 모델링과 시뮬레이션에 관한 연구)

  • Kang Yu-Jung;Hao Chen;Ahn Jin-Woo
    • Proceedings of the KIPE Conference
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    • 2002.07a
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    • pp.403-406
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    • 2002
  • The paper presents the componet parts and their models for the switched reluctance motor drive system with the angle position-current chopping control and with the fixed angle pulse width modulation control. The calculation of the parameters and the simulated models based on the MATHLAB SIMULINK software package are introduced by a four-phase 8/6 structure prototype with the four-phase asymmetric bridge ower converter. The simulation of the prototype in the course of starting is made by the simulated models at the different control strategies and speeds.

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Islanding Detection for PV System Connected to a Utility Grid

  • Han, Seok-Woo;Mok, Hyung-Soo;Choe, Gyu-Ha
    • Proceedings of the KIPE Conference
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    • 1998.10a
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    • pp.719-723
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    • 1998
  • Prevention of the islanding phenomena is one of the most important issues because it can damage electrical equipment connected to the utility system and endanger human life. It is very difficult to detect an islanding condition of a power distribution line with conventional voltage of frequency relays, while the output power and the load power of utility interactive PV inverter units are in nearly balanced state in both active power and reactive power. This paper describes the protective equipment that prevents the PV system connected to the utility grid from starting islanding. Both predictive ocntrol method and harmonic injection method are used for a current control and islanding detection for operating safety.

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Analysis and Implementation of ANFIS-based Rotor Position Controller for BLDC Motors

  • Navaneethakkannan, C.;Sudha, M.
    • Journal of Power Electronics
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    • v.16 no.2
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    • pp.564-571
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    • 2016
  • This study proposes an adaptive neuro-fuzzy inference system (ANFIS)-based rotor position controller for brushless direct current (BLDC) motors to improve the control performance of the drive under transient and steady-state conditions. The dynamic response of a BLDC motor to the proposed ANFIS controller is considered as standard reference input. The effectiveness of the proposed controller is compared with that of the proportional integral derivative (PID) controller and fuzzy PID controller. The proposed controller solves the problem of nonlinearities and uncertainties caused by the reference input changes of BLDC motors and guarantees a fast and accurate dynamic response with an outstanding steady-state performance. Furthermore, the ANFIS controller provides low torque ripples and high starting torque. The detailed study includes a MATLAB-based simulation and an experimental prototype to illustrate the feasibility of the proposed topology.

A Study of High Efficiency Electrodeless lamp Properties (고효율 신광원 시스템의 특성에 관한 연구)

  • Kim, H.S.;Lee, S.H.;Shin, S.W.;Lim, J.M.;Huh, S.K.;Hwang, M.K.
    • Proceedings of the KIEE Conference
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    • 2002.07c
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    • pp.1717-1720
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    • 2002
  • Electrodeless discharge lamps have been objects of interest and research for several decades, mainly because of their potential for extremely long life, high lamp efficacies and smaller than standard fluorescent lamps size. A series of measurements and observations concerning variables has yielded optical and electrical characteristics for electrodeless discharge lamp like incandescent lamp and circular lamp feature. Last experiment were carried out to determine the lamp temperature at several surface points during operation. Light output levels in excess over 60,000 cd/$m^2$ have been measured in electrodeless discharge lamp for a general of conditions. At lamp surface temperatures have been measured over $80^{\circ}C$, and starting current have been measured over ${\sim}A$.

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An analysis of transient state for induction motor by using the magnetic equivalent circuit method (자기등가회로법에 의한 유도전동기 과도상태해석)

  • Jeong, Jong-Ho;Lee, Eun-Woong;Cho, Hyun-Kil;Kim, Jun-Ho;Lee, Hwa-Su
    • Proceedings of the KIEE Conference
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    • 2002.11d
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    • pp.18-20
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    • 2002
  • In this paper, the construction elements of the induction motor was represented by the magnetic tube. The magnetic tube is basis of the magnetic equivalent circuit. The magnetic equivalent circuit method is convenient of complicated analysis of the transient state of the induction motor. Because the method is restriction on only one direction of magnetic flux. Air gap magnetomotive force was calculated by magnetic equivalent circuit method. Starting transient torque and phase current of the induction motor was confirmed by the theoretical calculation and the experiments.

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Analysis and test of dynamic characteristics of induction motor (유도 전동기의 동특성 해석 및 시험)

  • Jang, S.M.;Park, P.I.;Lee, S.H.;Lee, S.L.;Yoon, K.G.
    • Proceedings of the KIEE Conference
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    • 1999.11b
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    • pp.55-57
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    • 1999
  • To control induction motor we have to know about dynamic characteristics including torque characteristic. Simulation and test were made to get dynamic characteristics using LabVIEW and Matlab. We got experimental results(e.g current, torque, speed etc) from starting to steady state with changing of load.

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GEOTAIL SPACECRAFT OBSERVATIONS OF NEAR-TAIL DIPOLARIZATION AND PLASMA FLOW DURING THE SUBSTORM EXPANSION

  • Lee, D.Y.;Min, K.W.;Lee, E.S.
    • Journal of Astronomy and Space Sciences
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    • v.17 no.2
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    • pp.141-146
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    • 2000
  • Some observational features on the July 5, 1995 substorm event are presented using the data from the Geotail satellite which was located at near-Earth plasma sheet, ${X}_{GSE}$$-9.6R_{E}$, and quite close to the onset sector. Near-tail magnetic field reveals the typical dipolarizations starting ar ∼ 11-4 UT until ∼ 1113 UT. During the interval, two dipolarizations occur: First dipolarization is not strong and accompanies only weak(<150km/s) earthward/dawnward plasma flows, and in the second dipolarization that follows shortly, rather large amplitude magnetic fluctuations are seen, but it initiates with no significant earthward flow. The earthward bursty flow with a maximum speed of > 450km/s was observed, but delayed by ∼ 1 min with respect to the second dipolarization initiation. These features are in conflict with the flow-braking scenario for the substorm. Rather they fit better in the near-tail current disruption scenario.

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The wind tunnel measuring methods for wind turbine rotor blades

  • Vardar, Ali;Eker, Bulent
    • Wind and Structures
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    • v.7 no.5
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    • pp.305-316
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    • 2004
  • In this study, a wind tunnel, that has been developed for experiments of wind turbine rotor blades, has been considered. The deviations of the measurements have been examined after this wind tunnel had been introduced and the measurements on it had been explained. Two different wind turbine rotor blades miniatures have been used for getting better results from the experiments. The accuracy of measurements have been experimented three times repetitively and examined statistically. As a result, wind speed values which this type of wind tunnel and wind turbine rotors need for starting, wind speed in the tunnel, temperature and moisture values, the number of rotor's revolution, and the voltage that is produced in 102 ${\Omega}$ resistance and current values have been determined to be fixed by measurements used. This type of wind tunnel and wind turbine rotor' performance difference and the difference of revolution figures have been determined to be fixed by measurements used.

Induction Motors Performance Study under Various Voltage Sags Using Simulation

  • Ojaghi, Mansour;Faiz, Jawad;Shahrouzi, Hamid;Alimohammadi, Sahar
    • Journal of international Conference on Electrical Machines and Systems
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    • v.1 no.3
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    • pp.295-302
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    • 2012
  • The main aim of this paper is to study effects of different voltage sags and their intensity on the behavior of induction motors using a simulation approach. For this purpose, necessary simulation was done in Matlab - Simulink first. Then, to ensure-reasonable accuracy of the simulation, some results of the simulation were compared with the corresponding results measured in the laboratory. Then effects of intensity of symmetric voltage sag (three phase) and its starting point on the behavior of small and large induction motors was studied using simulation and subsequently, the effects of asymmetric voltage sags (single phase and two phase) has also been studied and finally the conclusion of the study was presented.