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3상 히터의 불평형전류 검출에 의한 결함예측 및 보호장치의 선정
이문형 ( Mun Hyung Lee ),정재희 ( Jae Hee Jung ) 한국안전학회(구 한국산업안전학회) 2015 한국안전학회지 Vol.30 No.1
Three phase heaters in 7 buildings of 2 sites were examined for precise diagnosis. The sample size was 626. Precise examinations of current and the heater wiring status revealed contact failures and arcs in equipments that had CUF larger than 10%. Contact failures and arcs may cause electrical fire. Therefore, the correlation between the CUF and the imperfections in heater equipment and its wiring was analyzed for three phase heaters. In addition, the protection devices used for detection of heater imperfections were found to be unsuitable for the purpose. Current status of the protection devices was analyzed, and suggestions for improvements were made for new standards of the protection device selection
3상 저항가열식 전기히터의 화재예방을 위한 결함 진단장치
이문형(Mun-Hyung Lee),김찬오(Chan-O Kim) 대한전기학회 2017 전기학회논문지 Vol.66 No.11
In this study, We have discussed the development of a diagnostic device to detect and prevent electrical fire due to the arc caused by contact failure and partial disconnection at the connection part of the three-phase electric heater wiring used in the industrial field. The arc caused by contact failure and partial disconnection at the connection part of the electric heater shows a change in the current effective value. Therefore, it is possible to determine whether there exists a defect by analyzing the current unbalance factor and the number of current fluctuations with the diagnostic apparatus. The three-phase unbalanced heater is considered to be capable of determining defects through periodic measurement and trend analysis of the current unbalance factor. It is also expected that this device can be used not only for electric heaters but also for detection of defects in wiring and connections of electrical equipment having a characteristic of constant load current.
3개 공단내 업종별 최적 영양염류 제거공정에 관한 연구
김인수,황문현,김미영,이문형 ( In S . Kim,Mun Hyun Hwang,Mi Young Kim,Mun Hyung Lee ) 한국물환경학회 1997 한국물환경학회지 Vol.13 No.2
Nutrient removal in the effluent of manufacturing company is considered to be the major control parameter to prevent and reduce the risk of eutrophication and red tide problems occurring in lakes, reservoir, and coastal area. Twenty eight companies out of three industrial complex(Chungju, Yeochon, Iksan) producing more than 60㎎/L of total nitrogen(T-N) in the effluent were selected for detailed study. Existing treatment processes, concentrations of wastewater, and flowrate were throughly investigated. Mean values of T-N concentration from Chungju, Yeochon, and Iksan industrial complex were 297, 204, 1,613㎎/L, respectively. However, those concentrations were mostly influenced by one or few companies discharging significantly high nitrogen effluent Optimum treatment processes were proposed to bring the effluent nitrogen concentration below the regulated level using market-available technologies.