• Title/Summary/Keyword: resistance measurement

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Temperature Measurement Techniques for RAON Cryomodule

  • Kim, Heetae;Jung, Yoochul;Jo, Yong Woo;Lee, Min Ki;Choi, Jong Wan;Kim, Youngkwon;Kim, Juwan;Paeng, Won-Gi;Kim, Moo Sang;Jung, Hoechun;Kwon, Young Kwan
    • Applied Science and Convergence Technology
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    • v.27 no.2
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    • pp.30-34
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    • 2018
  • Conducting and semiconducting temperature sensors are calibrated and applied to cryomodules. The definition of temperature is introduced and the pressure in vacuum is shown as a function of temperature. The resistance of Drude model is shown as a function of carrier density and mean free path. Temperature sensors are calibrated with Physical Property Measurement System (PPMS). The temperature sensors are applied to measure temperature accurately in RAON cryomodules.

On-Site Evaluation Technique of Linearity for Ratio Error and Phase Angle Error of Current Transformer Comparison Measurement Equipment (전류변성기 비교 측정 장치의 비오차 및 위상각 오차의 직선성 현장 평가기술)

  • Jung, Jae-Kap;Kwon, Sung-Won;Lee, Sang-Hwa;Kang, Jeon-Hong;Kim, Myung-Soo
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.55 no.6
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    • pp.313-316
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    • 2006
  • A method for evaluation of the linearity of both the ratio error and phase angle error in the current transformer(CT) comparison measurement equipment has been developed by employing the standard resistors with negligible AC-DC resistance difference less than $10^{-5}$. The non-reactive standard resistors for the linearity check of the system are used as the external burden connected with the secondary of CT under test. These burdens consist of nine standard resistors, with the nominal resistance of $0.01{\Omega},\;0.1{\Omega},\;0.2{\Omega},\;0.4{\Omega},\;0.6{\Omega},\;1{\Omega},\;2{\Omega},\;4{\Omega}$, and $10{\Omega}$. For linearity check, the developed method has been applied in the CT comparison measurement equipment belonging to the industry.

Site Evaluation and Application of the On-line and Off-line Test for the 13[kV] Class Hydropower Generator Stator Windings (13[kV]급 수력발전기 고정자 권선의 운전 및 정지 중 진단시험 현장적용 평가 및 분석)

  • Chang, Jeong-Ho;Lee, Dong-Keun;Lee, Heung-Ho
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.25 no.11
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    • pp.73-82
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    • 2011
  • The solid insulation system of stator windings in high voltage rotational machines is usually aging in accordance with long time operation. The partial discharge test have been known to check whether insulation deterioration exist or not, and the PD test can effectively diagnose a solid insulation condition regardless of during operation(on-line) or not(off-line). The on-line PD measurement have proven to be a successful technique in monitoring stator insulation condition nowadays. This paper describes the characteristics of comparing the on-line PD measurement data using PDMS-HG(Partial Discharge Monitoring System for Hydro-electric Generator) installed in field with the off-line diagnosis measurement data(insulation resistance, winding resistance, PI, ${\Delta}tan{\delta}$ and PD) on hydro generator(13[kV]) stator windings. These results make good use of managing rotational machines through evaluating the solid insulation condition of stator windings.

Analysis of the Frequency Dependent Characteristics of Ground Impedance of a Ground Rod (봉상접지전극의 접지임피던스의 주파수의존성의 분석)

  • 이복희;엄주홍
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.53 no.8
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    • pp.426-432
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    • 2004
  • This paper presents a systematic approach of measurement, modeling and analysis of grounding system impedance in the field of lightning protection system and intelligent power equipments. The measurement and analysis system of ground impedance is based on a computer aided technique. The magnitude and phase of ground impedance were determined by the novel measurement and analysis using the revised fall-of-potential method. The ground impedances of the ground rod of 50 m long are considerably dependent on the frequency. The ground impedance is mainly resistive in the frequency range of 3-20 kHz. At higher frequencies, the reactive components of the ground impedances are no longer negligible and the inductance of the ground rod was found to be the core factor deciding the ground impedance. Although the steady-state ground resistance of the ground rod of 50 m was less than that of the ground rod of 10 m, the ground impedances of the ground rod of 50 m over the frequency range of more than 60 kHz were much greater than those of the ground rod of 10 m. Furthermore, the equivalent circuit model based on the measured data was proposed. and the calculated results were in approximately agreement with the measured data.

Temperature Measurement System for Refrigerated Vehicle (냉동차량을 위한 온도 측정 시스템)

  • Lim, Yong-Jin;Kim, Jung-Hwan;Lim, Joon-hong
    • Journal of IKEEE
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    • v.23 no.1
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    • pp.159-163
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    • 2019
  • The food service industry has been grown due to improvement of living standards. In addition, the demand for frozen food delivery is increasing day by day at online/offline and the refrigerated vehicles are used in most of these food distributions. One of the most important factors in a refrigerated car is to measure the temperature accurately. Conventional temperature recording systems are generally connected directly to temperature sensor modules. Since the temperature data are transmitted to the temperature recorder by using the electric wire, there is a disadvantage that the resistance error must be compensated according to the cable length. In this paper, we propose a method to correct errors due to cable resistance using digital processing and CAN (Controller Area Network) communication. We use PT-1000 platinum sensor to increase the accuracy of the temperature measurement.

Effects of 8-Week Elastic Resistance Exercise on Knee Isokinetic Rate of Velocity Development and Balance by Age

  • Youngmin Choi;Kihong Kim;Hwanjong Jeong
    • International journal of advanced smart convergence
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    • v.12 no.4
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    • pp.395-406
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    • 2023
  • Ten women in their 20s and 10 women in their 50s were selected to investigate the effect of an elastic band exercise program for 8 weeks according to age on women's knee speed expression rate and balance. Knee isokinetic muscle strength measurement, single-legged standing with eyes closed, and YBT were performed 1 week before and after the exercise program. The measured data were analyzed through a mixed design two-way ANOVA, and if there was a significant difference, post hoc verification was performed using the bonferoni method. In our study, as a result of an 8-week elastic band exercise program, there was no difference in the speed development rate according to the measurement period, and the speed development rate according to age was found to be higher in people in their 50s than in their 20s. In our study, there was no difference in balance ability depending on the measurement period, and there was also no difference in balance ability depending on age. Discussing the results of our study, we found that 8 weeks of elastic band exercise cannot bring about significant changes in speed development ability and balance ability, which become more accurate with age.