• Title/Summary/Keyword: component state test

Search Result 132, Processing Time 0.025 seconds

Development of Solid State Relay(SSR) Life Prediction Device for Glass Forming Machine (유리 성형기의 무접점릴레이(SSR) 수명 예측장치 개발)

  • Yang, Sung-Kyu;Kim, Gab-Soon
    • Journal of the Korean Society of Manufacturing Process Engineers
    • /
    • v.21 no.2
    • /
    • pp.46-53
    • /
    • 2022
  • This paper presents the design and manufacture of a Solid State Relay (SSR) life prediction device that can predict the lifetime of an SSR, which is a key component of a glass forming machine. The lifetime of an SSR is over when the current supplied to the relay is overcurrent (20 A or higher), and the operating time is 100,000 h or longer. Therefore, the life prediction device for the SSR was designed using DSP to accurately read the current and temperature values from the current and temperature sensors, respectively. The characteristic test of the manufactured non-contact relay life prediction device confirmed that the current and temperature were safely measured. Thus, the SSR lifetime prediction device developed in this study can be used to predict the lifetime of an SSR attached to a glass forming machine.

Estimation of Remaining Useful Life for Bearing of Wind Turbine based on Classification of Trend (상태지수의 경향성 분류에 기반한 풍력발전기 베어링 잔여수명 추정)

  • Yun-Ho Seo;SangRyul Kim;Pyung-Sik Ma;Jung-Han Woo;Dong-Joon Kim
    • Journal of Wind Energy
    • /
    • v.14 no.3
    • /
    • pp.34-42
    • /
    • 2023
  • The reduction of operation and maintenance (O&M) costs is a critical factor in determining the competitiveness of wind energy. Predictive maintenance based on the estimation of remaining useful life (RUL) is a key technology to reduce logistic costs and increase the availability of wind turbines. Although a mechanical component usually has sudden changes during operation, most RUL estimation methods use the trend of a state index over the whole operation period. Therefore, overestimation of RUL causes confusion in O&M plans and reduces the effect of predictive maintenance. In this paper, two RUL estimation methods (load based and data driven) are proposed for the bearings of a wind turbine with the results of trend classification, which differentiates constant and increasing states of the state index. The proposed estimation method is applied to a bearing degradation test, which shows a conservative estimation of RUL.

Chanties in the Chemical Components and Microorganisms in Sogokju-Mash during Brewing (소곡주의 양조과정중 술덧성분과 미생물의 변화)

  • 소명환
    • The Korean Journal of Food And Nutrition
    • /
    • v.5 no.2
    • /
    • pp.69-76
    • /
    • 1992
  • Sogokju, an old Korean rice wine, was brewed in laboratory scale in February, 1978, and the changes in chemical component and microorganisms in wine mash were investigated during brewing. In the course of first-mash brewing, lactic acid bacteria became the most predominant microflora in 3 days of fermentation lowering the pH of mash to 4.2. But at 7 days, the most predominant microorganism was changed from lactic acid bacteria to least, pH reached 3.6, and the saccharogenic activity of mash was reduced from initial 10 to 3.6. During second-mash brewing, remarkable changes did not occurred in pH and acidity, maintaining 3.5∼3.7 of pH and 8.0∼8.8 of acidity. Ethanol fermentation was proceeded vigorously until 20 days of fermentation, but it reached stationary state with 18.5% ethanol after 40 days, leaving reducing sugar unfermented in mash. Even if saccharogenic activity continued all during fermentation, it was thought to be too weak. The final product of Sogokju filterate, fermented for 60 day, contained 18.8% ethanol, 5.0% reducing sugar,0.4:1 total acid, 0.057% volatile acid, 0.206% amino acid and 7.3% extract. In sensory test, Sogokju scored good marks with similar level to commercial Bupju or Chungju. It had pale yellow color, gentle Nuluk-flavor and acid taste just a little strong.

  • PDF

Performance Improvement of Protective Relaying for Large Transformer by Using Voltage-Current Trend and Flux-Differential Current Slope Characteristic (전압-전류 추이와 자속-차전류 기울기 특성을 이용한 변압기 보호계전기법의 성능 개선)

  • Park, Chul-Won;Park, Jae-Sae;Jung, Yun-Man;Ha, Kyung-Jae;Shin, Myong-Chul
    • The Transactions of the Korean Institute of Electrical Engineers P
    • /
    • v.53 no.2
    • /
    • pp.43-50
    • /
    • 2004
  • Percentage differential characteristic relaying(PDR) has been recognized as the principal basis for power transformer protection. Second harmonic restraint PDR has been widely used for magnetizing inrush in practice. Nowadays, relaying signals can contain 2nd harmonic component to a large extent even in a normal state, and 2nd harmonic ratio indicates a tendency of relative reduction because of the advancement of material. Further, as the power system voltage becomes higher and more underground cables are used, larger 2nd harmonic component in the differential current under internal fault is observed. And then, conventional 2nd harmonic restraint PDR exposes some doubt in reliability. It is, therefore, necessary to develop a new algorithm for performance improvement of conventional protective relaying. This paper proposes an advanced protective relaying algorithm by using voltage-current trend and flux-differential current slope characteristic. To evaluate the performance of the proposed algorithm, we have made comparative studies of PDR, fuzzy relaying and DWT relaying. The paper is constructed power system model including power transformer, utilizing the WatATP, and data collection is made through simulation of various internal faults and inrush. As the results of test, the new proposed algorithm was proven to be faster and more reliable.

Ship Dynamics Modeling Based on Multivariate Identification by Linear Combination of Principal Components (주성분의 선형 결합을 통한 다변수 식별에 기반한 선박 조종 운동 모델 개발)

  • Dong-Hwan Kim;Minchang Kim;Seungbeom Lee;Jeonghwa Seo
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.61 no.4
    • /
    • pp.247-257
    • /
    • 2024
  • The present study suggests a data-driven multivariate identification method based on principal component analysis and shows an application to ship dynamics modeling in maneuver. A reduced order model of ship dynamics is built by linear combination of three principal components acquired from large angle zigzag maneuver test. For a given kinematic state with three variables, a proper span is found by least square method, therefore accompanying hydrodynamic force and moment is determined. Suggested dynamics model correctly estimates hydrodynamic force and moment, thus it showed good agreement in maneuver simulation with that of conventional ship dynamics model obtained by system identification of captive model tests.

A Study on High Temperature Creep and Stress Relaxation Properties of Zr-4 (Zr-4의 고온 크리프 및 응력이완 특성에 관한 연구)

  • Oh, Sea-Kyoo;Park, Chung-Bae;Han, Sang-Deok
    • Journal of the Korean Society of Fisheries and Ocean Technology
    • /
    • v.28 no.1
    • /
    • pp.71-78
    • /
    • 1992
  • Zr-4 used for a cladding and an end plug of reactor component has creep deformation under operation at high temperature. Creep is regarded as the time dependent deformation of a material under constant applied stress. Although the major source of the deformation of zirconium component in water-cooled reactors is irradiation creep, the thermal creep may give a rise to significant deformation in reactor component especially at relatively high temperatures and at various constant stresses, and therefore it must be predicted accurately. Stress relaxation is the time dependent change of stress at constant strain and it is a process related intimately to creep. In this paper, the creep behavior and stress relaxation of Zr-4 is examined at the temperature of 50$0^{\circ}C$ that is 40% of the absolute melting temperature of Zr-4 under the stress below yield stress and under the various constant strains. The results obtained are summarized as follows: 1) With an increase of stress, the steady state creep rate increases and the creep rupture time decreases. 2) The steady state creep rate $\varepsilon$(%/s) for the stress $\sigma$sub(c) (kgf/mm super(2)) of Zr-4 increases outstandingly. All the empirical equations computed for Zr-4 increases outstandingly. All the empirical equations computed for Zr-4 are in accord with Norton's model equation($\varepsilon$=K$\sigma$ sub(c) super (n)). The constants of materials computed are as follows: K=3.9881$\times$10 super(-5), n=1.9608 3) The rupture time T sub(r) (hr) decreases linearly with the increase of stress on the log-log scaled graph. The empirical equations computed for Zr-4 are in accord with Bailey's model equation (T sub(r)=K sub(1)$\sigma$sub(c) super(m)). The constants of materials computed are as follows: K sub(1)=1.2875$\times$10 super(16), m=-3.467 4) It seems clear that the strain could be quantitatively dependent on the high temperature creep properties such as creep stress, rupture time, steady state creep rate and total creep rate. It is found that these relationships are linear on the log-log graph. 5) In stress relaxation test, as the critical constant strain that can be allowed to the specimen is larger, stress relaxation becomes more rapid, and as the constant strain is smaller, the stress relaxation becomes slower.

  • PDF

Compensation of the Secondary Voltage of a Three Winding Coupling Capacitor Voltage Transformer (3권선 CCVT의 2차 전압 보상 방법)

  • Kang, Yong-Cheol;Kim, Yeon-Hee;Zheng, Tai-Ying;Jang, Sung-Il;Kim, Yong-Gyun
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.57 no.6
    • /
    • pp.938-943
    • /
    • 2008
  • Coupling capacitor voltage transformers(CCVTs) have been used in extra or ultra high voltage systems to obtain the standard low voltage signal for protection and measurement. For fast suppression of the phenomenon of ferroresonance, three winding CCVTs are used instead of two winding CCVTs. A tuning reactor is connected between a capacitor voltage divider and a voltage transformer to reduce the phase angle difference between the primary and secondary voltages in the steady state. Slight distortion of the secondary voltage is generated when no fault occurs. However, when a fault occurs, the secondary voltage of the CCVT has significant errors due to the transient components such as dc offset component and/or high frequency components resulting from the fault. This paper proposes an algorithm for compensating the secondary voltage of a three winding CCVT in the time domain. With the values of the measured secondary voltage of the three winding CCVT, the secondary, tertiary and primary currents and voltages are estimated; then the voltages across the capacitor and the tuning reactor are calculated and then added to the measured voltage. Test results indicate that the algorithm can successfully compensate the distorted secondary voltage of the three winding CCVT irrespective of the fault distance, the fault impedance and the fault inception angle as well as in the steady state.

The Allocation of Inspection Efforts Using a Knowledge Based System

  • Kang, Kyong-sik;Stylianides, Christodoulos;La, Seung-houn
    • Journal of Korean Society for Quality Management
    • /
    • v.18 no.2
    • /
    • pp.18-24
    • /
    • 1990
  • The location of inspection stations is a significant component of production systems. In this paper, a prototype expert system is designed for deciding the optimal location of inspection stations. The production system is defined as a single channel of n serial operation stations. The potential inspection station can be located after any of the operation stations. Nonconforming units are generated from a compound binomial distribution with known parameters at any given operation station. Traditionally Dynamic programming, Zero-one integer programming, or Non-linear programming techniques are used to solve this problem. However a problem with these techniques is that the computation time becomes prohibitively large when t be number of potential inspection stations are fifteen or more. An expert system has the potential to solve this problem using a rule-based system to determine the near optimal location of inspection stations. This prototype expert system is divided into a static database, a dynamic database and a knowledge base. Based on defined production systems, the sophisticated rules are generated by the simulator as a part of the knowledge base. A generate-and-test inference mechanism is utilized to search the solution space by applying appropriate symbolic and quantitative rules based on input data. The goal of the system is to determine the location of inspection stations while minimizing total cost.

  • PDF

A Relativistiv Configuration Interaction Method Using Effective Core Potentials with Spin-Orbit Interactions

  • 김명청;이상연;이윤섭
    • Bulletin of the Korean Chemical Society
    • /
    • v.16 no.6
    • /
    • pp.547-552
    • /
    • 1995
  • As an extension to the Kramers' restricted Hartree-Fock (KRHF) method [J. Comp. Chem., 13, 595 (1992)], we have implemented the Kramers' restricted configuration interaction (KRCI) program in order to calculate excited states as well as the ground state of polyatomic molecules containing heavy atoms. This KRCI is based on determinants composed of the two-component molecular spinors which are generated from KRHF calculations. The Hamiltonian employed in the KRHF and KRCI methods contains most of all the important relativistic effects including spin-orbit terms through the use of relativistic effective core potentials (REP). The present program which is limited to a small configuration space has been tested for a few atoms and molecules. Excitation energies of the group 14 and 16 elements calculated using the present KRCI program are in good accordance with the spectroscopic data. Calculated excitation energies for many Rydberg states of K and Cs indicate that spin-orbit terms in the REP, which are derived for the ground state, are also reliable for the description of highly excited states. The electronic states of the polyatomic molecule CH3I are probed from the molecular region to the dissociation limit. Test calculations demonstrate that the present KRCI is a useful method for the description of potential energy surface of polyatomic molecules containing heavy atoms.

Structural and component characterization of the B4C neutron conversion layer deposited by magnetron sputtering

  • Jingtao Zhu;Yang Liu;Jianrong Zhou;Zehua Yang;Hangyu Zhu;Xiaojuan Zhou;Jinhao Tan;Mingqi Cui;Zhijia Sun
    • Nuclear Engineering and Technology
    • /
    • v.55 no.9
    • /
    • pp.3121-3125
    • /
    • 2023
  • Neutron conversion detectors that use 10B-enriched boron carbide are feasible alternatives to 3He-based detectors. We prepared boron carbide films at micron-scale thickness using direct-current magnetron sputtering. The structural characteristics of natural B4C films, including density, roughness, crystallization, and purity, were analyzed using grazing incidence X-ray reflectivity, X-ray diffraction, X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, and scanning electron microscopy. A beam profile test was conducted to verify the practicality of the 10B-enriched B4C neutron conversion layer. A clear profile indicated the high quality of the neutron conversion of the boron carbide layer.