• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.1374-1376
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• 2000

In this paper, sample coils for stator form-wound winding of traction motor were tested by the accelerative thermal degradation, which composed of heat, vibration, moisture and overvoltage applying. Reliability and expected life were evaluated on the insulation system for 200 class traction motor. After aging of 10 cycles, insulation resistance and PI properties were investigated as diagnosis tests in the range of $20{\sim}160^{\circ}C$. Analysis of polarization properties was performed on the base of do current-time change.

• 한국정밀공학회지
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• 제24권6호
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• pp.72-77
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• 2007

A safety-related equipment for the nuclear power plant should be needed an equipment qualification. In this paper, the approach, methods, philosophies, and procedures for qualifying the large squirrel-cage induction electric pump motors for use in ULCHIN 5, 6 Nuclear Power Plants were presented. The method of qualification is a combination of experimental test and analytic method, which is composed of radiation exposure test, seismic simulation test, thermal aging analysis for non-metallic materials, and seismic analysis. The results showed that the motor performed its safety function with no failure mechanism under postulated service conditions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2175-2178
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• 2005

During normal machine operation, partial discharge(PD) measurements were performed with turbine generator analyzer(TGA) in five high voltage motors(rated 6.6kV). These high voltage motors were installed with 80pF capacitive couplers at the terminal box. The PD patterns were displayed two dimensional and three dimensional. TGA summarizes each plot with two quantities such as the normalized quantity number(NQN) and the peak PD magnitude(Qm). Off-line PD measurements were conducted on five motors. These motors were energized to 3.81kV. The PD levels in pC were measured with a conventional digital PD detector. The comparison of positive to negative PD indicates whether the defect elements of PD are within the insulation or on the insulation surface. Internal discharges were generated in phase A, B and C of COP-B and pulv.-B, in phase B of Pulv. C and in phase C of Pulv.-D motor. Discharge at conductor surface was discovered in phase A of Pulv. D motor. Slot discharges occurred in three phases of Pulv. E motor.

• Elastomers and Composites
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• 제40권2호
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• pp.119-127
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• 2005

고무부품의 신뢰성을 확보하기 위해서 고무재료의 물성파악과 수명평가는 매우 중요하다 하겠다. 본 연구에서는 냉장고 콤프레샤 모터에서 발생되는 소음 및 진동 제어 목적으로 고무마운트에 사용되는 고무재료인 NBR과 EPDM에 대해 상온과 $70^{\circ}C,\;85^{\circ}C,\;100^{\circ}C$에서 75일 동안 노화시킨 상태에서 단축 인장과 이축 인장으로 물성시험을 수행하여 가교밀도, 100% 모듈러스 변화와 응력-변형률 관계를 파악하였다. 또한, 고무소재의 노화수명을 예측하기 위해 가속열 노화시험을 수행하여 시간-온도 환산식인 아레니우스 관계식을 구하였다.

• Korean Chemical Engineering Research
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• 제56권6호
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• pp.779-783
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• 2018

본 연구에서는 차량용 12 V 납축전지로 주로 사용되는 VRLA (Valve regulated lead acid) 배터리의 충/방전 특성과 노화에 따른 이의 변화를 수학적으로 모델링하였다. 기존에 리튬 이온 배터리의 거동 예측에 주로 이용되어 왔던 수학적 모델링 기법을 상용 70 Ah VRLA 배터리에 적용하였다. 정전류 충/방전에 따른 전압의 변화를 모델링 결과와 비교하였다. 비교 결과로부터 사용된 수학적 모델이 납축전지에도 높은 정확도로 적용될 수 있음을 알 수 있었다. 또한 이를 이용하여 납축전지의 노화를 예측할 수 있음을 확인하였다.

• 한국추진공학회지
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• 제24권6호
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• pp.101-107
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• 2020

본 논문에서는 HTPB/AP 계열의 추진제의 경화 온도를 변화시키는 Step 경화 방법으로 경화일 단축 연구를 진행하였다. 이 연구는 HTPB/AP 계열의 추진기관 제작 시 생산성 향상(제작기간 단축 및 치구회수율 증대)을 목적으로 한다. 정상 경화 대비 추진제의 기계적 물성을 비교하여 정상 경화 시 60℃ 5일 소요되는 경화일을 Step 경화로 4일(60℃ 1일 / 65℃ 3일)로 설정하였다. 경화일 단축을 적용 시 추진제 노화 특성을 알아보기 위해 Step 경화 후 후경화(Post-cure) 시험을 진행하였다. 이를 통해 기계적 물성 및 열팽창 계수를 측정하여 추진제의 후경화 특성을 분석하였다. 또한, Step 경화 후 가속 노화 시험을 진행하여 12주차 경과 후 인장시험을 수행하였다. 그 결과, Sm(bar)은 8 bar 이상, Em(%)은 40%이상으로 요구되는 우수한 기계적 물성을 가지는 것을 알 수 있었다.

• Journal of Biosystems Engineering
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• 제34권6호
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• pp.391-396
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• 2009

The percentage of those aged 60 and over is 43.5% among our country's 3,186 thousands farming population, so farm village is getting aging society rapidly. Moreover agricultural competitiveness has being weakened due to labor shortage by degradation in quality of labor configuration from elderly porson. For realisms easy workability, we developed a motor vehicle for agricultural activity. The vehicle has an automatic guidance system which could follows a track of magnetic tape on the floor for easy moving to given working position. We collected data from two guidance sensors, located on front and rear end of the vehicle and calculated displacement and angle deviation from the track. This traveling system was stably controlled with processing information deflection S, angle of deviation, D and angle velocity, Vt = $k_1D$ - $k_2S$ from two guidance sensors attached on front and rear of th motor vehicle. Also this system have been tested under various condition of $k_1$, $k_2$ for comparison on both stepped and turning routes. The results show that traveling performance is best at $k_1$=0.7, $k_2$=3.

• Journal of Mechanical Science and Technology
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• 제19권6호
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• pp.1229-1242
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• 2005

When natural rubber is used for a long period of time, it becomes aged; it usually becomes hardened and loses its damping capability. This aging process affects not only the material property but also the (fatigue) life of natural rubber. In this paper the aging effects on the material property and the fatigue life were experimentally investigated. In addition, several fatigue life prediction equations for natural rubber were proposed. In order to investigate the aging effects on the material property, the load-stretch ratio curves were plotted from the results of the tensile test, the compression test and the simple shear test for virgin and heat-aged rubber specimens. Rubber specimens were heat-aged in an oven at a temperature ranging from $50^{\circ}C$ to $90^{\circ}C$ for a period ranging from 2 days to 16 days. In order to investigate the aging effects on the fatigue life, fatigue tests were conducted for differently heat-aged hourglass-shaped and simple shear specimens. Moreover, finite element simulations were conducted for the specimens to calculate physical quantities occurring in the specimens such as the maximum value of the effective stress, the strain energy density, the first invariant of the Cauchy-Green deformation tensor and the maximum principal nominal strain. Then, four fatigue life prediction equations based on one of the physical quantities could be obtained by fitting the equations to the test data. Finally, the fatigue life of a rubber bush used in an automobile was predicted by using the prediction equations, and it was compared with the test data of the bush to evaluate the reliability of those equations.

• 한국융합학회논문지
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• 제11권6호
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• pp.173-182
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• 2020

우리나라는 2000년 이후 EU의 지구온난화에 따른 환경 규제 강화, 고유가 추세 그리고 농촌 인구분포의 고령화 등에 따라 친환경에너지를 기반으로 하는 농촌 소상공인을 위한 다목적 전기차에 대한 니즈 강화가 시장의 큰 흐름이 되고 있다. 농촌 소상공인을 위한 다목적 전기차는 적은 비용으로 유지가 가능하고 친환경 에너지의 활성화를 통한 온실 가스를 감축할 뿐 아니라 고령화 되어가고 있는 농업 종사자의 노동 강도를 줄이고 야간작업 및 물류 운반을 위하여 매우 혁신적인 운송수단이 될 것이다. 본 논문에서는 친환경 에너지 정책 시행과 함께 영세 규모의 농촌 소상공인들이 비포장도로와 웅덩이가 많은 농로환경에서 쉽게 운행할 수 있고, 농작물 운반 시 노동 강도를 줄일 수 있으며, 사고 시에도 저렴한 비용으로 간단하게 부품을 교체할 수 있는 농촌 다목적 모듈형 전기차를 제안하기 위하여 기존 문헌들을 고찰하고 국내외 전기차를 벤치마킹하여 12개의 모듈형 부품을 제시한다. 본 논문은 모듈형 전기차의 산업계는 물론 디자인계의 연구에 도움이 될 것으로 사료된다.

• 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.