• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2097-2099
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• 2005

Class-F and class-B insulating materials based on the resin rich type mica-epoxy composites for the stator windings in large turbine generators have been developed by DHIC. In recent, stator winding bars applied with prototype insulation tapes and commercially available resin rich groundwall tapes were produced through the same manufacturing processes as the real bars. Comparative tests to obtain the insulation properties of both bars were carried out such as IR/PI. dissipation factor and partial discharge at room temperature. In this paper, the manufacturing processes and the insulation properties of the bars which were not aged are presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2118-2122
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• 2005

This test was performed to assess the corelation of insulation deterioration condition with breakdown voltage of the stator winding of 3.3kV class induction motors which have been in service for 10 years after being installed in 1993. The insulation diagnostic tests include resistance, polarization index(P.I), dissipation factor$({\Delta}tan{\delta})$, maximum partial discharges (Qmax) and AC breakdown test. we evaluated the corelation of insulation diagnostic test with AC breakdown test for stator wilding of high voltage induction motor.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 추계학술대회논문집; 한국과학기술회관; 6 Nov. 1997
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• pp.222-226
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• 1997

The reproducibility of measured level is a prior condition for the reliable assessment of the sound insulation performance. To review the reproducibility of impact sound level, 20 floors were selected in highrise apartment house, and then impact sound levels of two kinds of typical floors were measured with 10 times in each receiving point. The impact sound insulation class values were derived with a standard tapping machine and bang machine. Inspection of the result showed that smaller scale of the room caused to lower the reproducibility and that the higher values of standard deviation in lower frequency caused to deteriorate the reliability of assesment. Thus to enhance the reproducibility of the impact sound insulation class, greater allowable deviation of measured level is required in lower frequency than in higher one.

• 한국초전도ㆍ저온공학회논문지
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• 제22권3호
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• pp.13-19
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• 2020

This study presents the experiment and simulation results on the magnetic field response and electrical stability behaviors of no-insulation (NI) and metal insulation with stainless steel tape (MI-SS) which wound in form of racetrack type coils. First of all, the structural design of the racetrack type bobbin was shown along with its parameters. Then, the current-voltage tests were carried out to measure the critical current of both test coils. Also, the sudden discharging and charging tests were performed in the steady state to estimate the decay field time and magnetic field response, respectively. Finally, the overcurrent tests were conducted in the transient state to investigate the electrical stability of these test coils. Based on the experimental results, the contact surface resistances were calculated and applied to the field coils (FCs) of 10-MW-class second generation high temperature superconducting generator (2G HTSG) used in wind offshore environment. The charging delay time and electrical stability for NI and MI-SS HTS FCs of 10-MW-class 2G HTSG are analyzed by the equivalent circuit model and the key parameters which were obtained from the electromagnetic finite element analysis results.

• 전기의세계
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• 제16권2호
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• pp.1-8
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• 1967

From the discovery of Alago's disk, a number of trials and efforts have been concentrated on a small-sized and light-weighted induction motor. They have devoted themseleves, however, mainly to a improvement of cooling effect, a proper weight-distribution of copper and iron and desirable number of slots. In consequence, such an effort restricted only to the field of design, has resulted in unsatisfactory developments in the insulating materials consisting of the main parts of an induction motor. The quality of fibre and paper which are used as class-A insulation materials with their "compound" and "varnish" has been increased to some extent. Similarly Class-B insulation materials like asbest mica has been almost a combination of inorganic and binding materials. But nowadays synthesic chemistry is making a remarkable progress. So it comes possible for us to have silicon resin and other good ones of similar charateristics. And even a thin silicon resin insures us to get excellent heat-pro f and insulation, so a better space factor and cost-down in motor design have come possible in most advanced nations of the world, but not in our country. Furthermore, a consideration of productivity and economy in manufacturing process has been neglected by a majority of engineers. This is more unpleasant und more undesirable. I think this rational method of induction motor design using new synthesic resin will devote in making your productivity and economy better. And the nation-wide standard value of electric motor size is sited here. size is sited here.

• 한국초전도ㆍ저온공학회논문지
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• 제5권3호
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• pp.48-51
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• 2003

HTS power transmission cable is expected to transport large electric power with a compact size. We are developing a 3-core, 22.9 kV, 50 MVA class HTS power cable, and each core consists of a conductor and shield wound with Bi-2223 tapes, electrical insulation with laminated polypropylene paper (LPP) impregnated with liquid nitrogen. This paper describes the design and experimental results of the model cable for the 22.9 kV, 50 MVA class HTS power transmission cable. The model cable was used the SUS tapes instead of HTS tapes because of testing the electrical characteristics only. The model cable was 1.3 m long and electrical insulation thickness was 4.5 mm. The model cable was evaluated the partial discharge (PD), AC and Impulse withstand voltage in liquid nitrogen. The AC and Impulse withstands voltage and PD inception stress was satisfied with the standard of Korea Electric Power Corporation (KEPCO) in the test results. The 3-core 22.9 kV, 50 MVA class HTS power cable has been designed and manufactured based on these experimental results.

• 조명전기설비학회논문지
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• 제21권10호
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• pp.141-149
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• 2007

본 논문은 유도전동기 고정자권선의 절연물에 대하여 비파괴 및 파괴시험을 실시하여 절연물의 비파괴특성과 내전압강도와의 상호관계를 비교, 평가, 분석함으로써, 향후 전동기의 절연상태 평가시 수명 및 절연진단의 신뢰성을 도모하고자 제안하였다. 본 논문에서는 비파괴시험과 파괴시험과의 상관관계를 평가하기위하여 비파괴시험으로 절연저항시험, 성극지수시험, 유전정접시험, 부분방전시험을 실시하였으며, 파괴시험은 60[kV] AC 내전압를 이용하여 실시하였다. 또한 장기간 사용된 전동기 권선의 절연물에 대한 연구결과로부터 기존 선진국의 진단방법 및 판정기준이 국내에서 제작된 전동기에 대한 절연특성 평가 및 분석에도 타당함을 증명하였으며, 향후 본 논문에서 제시한 자료들은 유사조건의 산업현장에서 운용중인 유도전동기의 수명 및 상태 평가를 위한 기초자료로 유용하게 사용될 수 있으리라 기대된다.

• 한국전기전자재료학회논문지
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• 제19권11호
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• pp.1067-1071
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• 2006

Prior to destructive testing, diagnostic tests were performed in ten high voltage motors. Diagnostic tests included polarization infer, ac current, dissipation factor$(tan{\delta})$ and partial discharge magnitude. The rewind of motet slater insulation at rated voltage is assessed by the results of these tests. After completing the diagnostic tests, the stator windings of motors were subjected to gradually increasing ac voltage, until the insulation punctured. No. 8 motor failed near rated voltage of 19.0 kV. The breakdown voltage of No. 4 motet was 7.0 kV which is lower that expected for good quality coils in 6.6 kV class motors. The failure was located in a line-end coil at the exit from the core slot. These two motors began operation in 1994. While testing No. 7 motor, flashover occurred between the stator winding and the stator frame at 15 kV. The relationship between the diagnostic test and the drop in insulation breakdown voltage was analyzed.

• 한국산업융합학회 논문집
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• 제20권5호
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• pp.425-430
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• 2017

This study propose CAE analysis of fire damper and design of the damper control system. Through the design of the damper system for ANSYS-CFX heat transfer. As a result of the analysis, continuance equation of the damper control. Climate system. Finaily, We have obtained a fire damper solution by using orthogonal array. The fire damper of the set of fixture and alveolus are made by using a CAE software. Also, the optimum design offshore structures. The new H-120 class fire damper was designed. In the near future, fire resistance test was carried out to obtain class H-120 thermal insulation of fire dampers according to a hydrocarbon fire conditions. The test results showed that the insulation of the damper blade was an important factor in the fireproof performance of fire dampers concerning the coaming length minimum 500mm on the unexposed side as specified test standard.

• 한국안전학회지
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• 제38권3호
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• pp.35-42
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• 2023

This study analyzed the current and temperature characteristics of major components of an induction motor during normal and abnormal operations as functions of the difference in the rated capacities of medium and large-sized motors widely used in industrial settings. The temperature rise equation of the induction motor winding was derived through locked-rotor operation experiments and linear regression analysis. When the ambient temperature is 40 ℃, the time to reach 155 ℃, the temperature limit of the insulation class (F class) of the winding of the induction motor, was confirmed to be 48 seconds for the 2.2 kW induction motor and 39 seconds for the 3.7 kW induction motor. This means that when the rated capacity is large or the installation environment is high temperature, the time to reach the temperature limit of the insulation class during locked-rotor operation is short, and the risk of insulation deterioration and fire is high. In addition, even if the EOCR (Electronic Over Current Relay) is installed, if the setting time is excessively set, the EOCR does not operate even if the normal and locked-rotor operation of the induction motor is repeated, and the temperature limit of the insulation grade of the winding of the induction motor is exceeded. The results of this study can be used for preventive measures such as the promotion of electrical and mechanical measures for the failure of induction motors and fire prevention in industrial sites, or the installation of fire alarm systems.