• Title, Summary, Keyword: Saturation Factor

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A Study on The characteristics based on the stauration effects of traction motor for korea High Speed Train (한국형 고속전철용 견인전동기의 포화현상에 따른 특성연구)

  • 이상우;김근웅;윤종학;한성수
    • Proceedings of the KSR Conference
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    • pp.360-367
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    • 1999
  • An inverter-driven induction motor is used as the traction motor for a high speed drive system that required safety, reliabillity, performance, compact size owing to the space and weight alloted for attaching to train, etc. particularly it is possible to happen the saturation effects of flux density at constant voltage-frequency region and then increase very higher than the at lowed capacity of no-load current and temperature in any case. therefore the optimum design of core, optimum voltage-frequency ratio, adoption of high grade magnetic core have been developed and researched for preventing these problems. this paper show the saturation effects of traction rotor by measuring the induced voltage of search coil at stator teeth and presents optimum voltage-frequency ratio as well as optimum core design through the comparison with efficiency, power factor, load current and no-load current for korea high speed train.

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High-Precision Contour Control by Gaussian Neural Network Controller for Industrial Articulated Robot Arm with Uncertainties

  • Zhang, Tao;Nakamura, Masatoshi
    • Transactions on Control, Automation and Systems Engineering
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    • v.3 no.4
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    • pp.272-282
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    • 2001
  • Uncertainties are the main reasons of deterioration of contour control of industrial articulated robot arm. In this paper, a high-precision contour control method was proposed to overcome some main uncertainties, such as torque saturation, system delay dynamics, interference between robot links, friction, and so on. Firstly, each considered factor of uncertainties was introduced briefly. Then proper realizable objective trajectory generation was presented to avoid torque saturation from objective trajectory. According to the model of industrial articulated robot arm, construction of Gaussian neural network controller with considering system delay dynamic, interference between robot links and friction was explained in detail. Finally, through the experiment and simulation, the effectiveness of proposed method was verified. Furthermore, based on the results it was shown that the Gaussian neural network controller can be also adapted for the various kinds of friction and high-speed motion of industrial articulated robot arm.

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Implementation of the Self-tuning Control Algorithm with an Input- amplitude Constraint (제어입력 크기가 제한되는 자기동조 제어알고리즘의 구현에 관한 연구)

  • 장효환;정회범
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.9
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    • pp.2153-2161
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    • 1993
  • Self-tuning control algorithms for an input-amplitude constrained system are developed and implemented. Magnitude of control input for small motors is generally restricted to narrow bound due to actuator saturation. The gain-adjusted control algorithm and the bounded-gain control algorithm proposed in this study yield smoother control input variations within the magnitude constraints comparing with the existing Clarke's suboptimal control algorithm. In the gain-adjusted control algorithm, the feedforward gain is adjusted using maximum gain, while in the bounded-gain control algorithm, the feedforward gain is bounded using weighting factor. For the DC servo motor control, the system performances of the proposed algorithms are compared with those of the existing algorithm by computer simulation and experiment. It is shown that the input variations of the proposed algorithms are smoother as compared with the existing algorithm.

Variation of Lane Utlization at Urban Signalized Intersections (신호교차로에서의 차선별 이용률의 산정 모형)

  • 오영태;심대영
    • Journal of Korean Society of Transportation
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    • v.12 no.1
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    • pp.117-132
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    • 1994
  • Drivers select approach lane according to various traffic situations as well as their destination. This behavior affects the utilization of lanes and capacity analysis at urban signalized intersections. This paper presents the concept, behavior of lane utilization, and the lane utilization factors which included in the study. Preparation of Korean Highway Capacity Manual (1992). Lane utilization is affected by various traffic and geometric factors which are roadway side friction, median friction, and number of lanes, etc. and it converges to an equal utilization as the degree of saturation (V/C ratio) increase. Lane utilization factor is suggested by the degree of saturation and the number of lanes, and it is presented in this paper.

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Arg243, Invariably Critical for the Transcriptional Activation of Yeast Gcn4p

  • Cho, Gyu-Chull;Lee, Jae-Yung;Kim, Joon
    • Journal of Microbiology
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    • v.37 no.3
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    • pp.154-158
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    • 1999
  • The arginine residue at position 243 (Arg 243) of the yeast transcription factor, Gcn4p, is invariably conserved among bZIP transcription factors. Using site-directed oligonucleotide saturation mutagenesis involving two-step polymerase chain reaction (PCR) amplification, random mutations were successfully introduced at the codon of 243 in the basic domain of Gcn4p. This mutant library was transformed ito Gcn4p defective yeast strain and selected for the transcriptionally active colonies. All colonies which were transcriptionally active had arginines in the codon 243. In this study, the strand preference by Taq polymerase during mutagenesis was also tested. Oligonucleotides were specially designed to test whether or not the polymerase was preferred using the strand as a template. A population of randomly mutated products were cloned into an appropriate vector and characterized by DNA sequencing analysis. Saturation mutagenesis which was performed efficiently by this method revealed a strong bias in terms of strand preference of Taq polymerase by an approximate ratio of 3 to 1 in this study.

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A Coupled Circuit and Field Analysis of a Stand-Alone Permanent-Magnet Synchronous Generator with Inset Rotor

  • Chan T. F.;Yan Lie-Tong;Lai L. L.
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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    • v.5B no.3
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    • pp.253-257
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    • 2005
  • By using a coupled circuit, time-stepping, two-dimensional finite element method (2-D FEM), the performance of a stand-alone permanent-magnet synchronous generator (PMSG) with inset rotor can be computed without involving the classical two-axis model. The effects of interpolar air gap length and armature resistance on the load characteristics are investigated. It is shown that the interpolar flux density, and hence the amount of voltage compensation, is affected by magnetic saturation. Validity of the coupled circuit and field analysis is confirmed by experiments on a prototype generator. The machine exhibits an approximately level load characteristic when it is supplying an isolated unity-power-factor load.

Enhancement of Color Images with Blue Sky Using Different Method for Sky and Non-Sky Regions

  • Ghimire, Deepak;Pant, Suresh Raj;Lee, Joonwhoan
    • Proceedings of the Korea Information Processing Society Conference
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    • pp.215-218
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    • 2013
  • In this paper, we proposed a method for enhancement of color images with sky regions. The input image is converted into HSV space and then sky and non-sky regions are separated. For sky region, saturation enhancement is performed for each pixel based on the enhancement factor calculated from the average saturation of its local neighborhood. On the other hand, for the non-sky region, the enhancement is applied only on the luminance value (V) component of the HSV color image, which is performed in two steps. The luminance enhancement, which is also called as dynamic range compression, is carried out using nonlinear transfer function. Again, each pixel is further enhanced for the adjustment of the image contrast depending upon the center pixel and its neighborhood pixel values. At last, the original H and V component image and enhanced S component image for the sky region, and original H and S component image and enhanced V component image for the non-sky region are converted back to RGB image.

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Saturation Headway of Through Movement at Signalized Intersections in Urban Area (도시부 신호교차로에서 직진이동류의 포화차두시간)

  • 이향숙;도철웅
    • Journal of Korean Society of Transportation
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    • v.20 no.5
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    • pp.23-31
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    • 2002
  • The headway of vehicles entering an intersection is closely related with the saturation flow rate and is a basic parameter required for determining the saturation headway and the start-up lost delay. Since such headway value reflects the drivers' behaviors and features of the intersection, all intersections don't have an equal value, but are affected by number and location of their lanes, changing types, local characteristics and time zone. Accordingly, this study attempted to suggest proper values on the basis of data by investigating headway in lanes. Number of exclusive through lanes was divided into single lane, double lanes and triple lanes, the locations of lanes were divided into inside lane, central lane and outside lane. As a result of investigating the headway, single through lane, double through lanes-inside lane, and triple through lane-outside lane showed as 1.73 sec., 1.71 sec. and 1.93sec., respectively. The result of calculating the area factor of business areas by fixing 1.00 for the residental area and applying relation between headway and saturation flow rate was 0.96. In the case of start-up lost delay lead dual left turn and directional separation were 1.41 sec. and 3.27 sec., respectively, showing the great difference. Therefore, different start-up lost delay according to changing type should be applied.

Measurement of Gas-Accessible PCE Saturation in Unsaturated Soil using Gas Tracers during the Removal of PCE (토양 내 PCE 제거과정에서 가스 분배추적자기법을 이용한 공기노출 PCE의 잔류량 검출)

  • Kim, Heon-Ki;Kwon, Han-Joon;Song, Young-Soo
    • Journal of Soil and Groundwater Environment
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    • v.16 no.5
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    • pp.42-52
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    • 2011
  • In this laboratory study, the changes in gas-exposed perchloroethene (PCE) saturation in sand during a PCE removal process were measured using gaseous tracers. The flux of fresh air through a glass column packed with PCEcontaminated, partially water-saturated sand drove the removal of PCE from the column. During the removal of PCE, methane, n-pentane, difluoromethane and chloroform were used as the non-reactive, PCE-partitioning, water-partitioning, and PCE and water-partitioning tracers, respectively. N-pentane was used to detect the PCE fraction exposed to the mobile gas. At water saturation of 0.11, only 65% of the PCE was found to be exposed to the mobile gas prior to the removal of PCE, as calculated from the n-pentane retardation factor. More PCE than that detected by n-pentane was depleted from the column due to volatilization through the aqueous phase. However, the ratio of gas-exposed to total PCE decreased on the removal of PCE, implying gas-exposed PCE was preferentially removed by vaporization. These results suggest that the water-insoluble, PCE-partitioning tracer (n-pentane in this study), along with other tracers, can be used to investigate the changes in fluid (including nonaqueous phase liquid) saturation and the removal mechanism during the remediation process.

Groundwater Quality and Contamination in the 'A' section of Seoul Metropolitan Subway (서울특별시 지하철 A설계구간에서의 지하수 수질 및 오염특성)

  • 이병선;우남칠
    • The Journal of Engineering Geology
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    • v.12 no.4
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    • pp.379-394
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    • 2002
  • This study was initiated to identify groundwater quality and contamination at present in the 'A' section of Seoul Metropolitan Subway. Groundwater samples were collected at 21 boreholes along the 'A' section and appeared to show mainly $Ca-HCO_3$ type. In 20 samples, concentration of $SO_4$, Cd, Pb, Fe, Mn, Al, F and $NO_3-N$ were higher than those of Korean drinking water quality standards. From chemical data and saturation Indices, contaminant sources of individual chemical elements were inferred to be buried wastes and surface sediments over the study area. The result of factor analysis suggested that the pollution factor should account for about 47% of data variation.