• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.2030-2031
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• 2007

This paper is purpose to understand the surge property for the shorted turn or shorted strand in high voltage motor stator windings. a shorted turn in high voltage motor windings causes a huge circulating current. and overheat windings, consequently burns the motor. a few shorted strands not cause winding failure immediately, but they increase the winding loss and temperature increase due to contact resistance. We carried out the surge test for three cases, normal winding, shorted turn winding and shorted strand winding. and we analyzed the test result.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제51권6호
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• pp.307-312
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• 2002

Inter-turn short circuits can have significant effects on a generator and its performance. The Inter-turn short circuits sensor for synchronous generator's field winding has been developed. The sensor, installed in the generator air-gap, senses the slot leakage flux of field winding and produces a voltage waveform proportional to the rate of change of the flux. For identification of reliability for sensor, a shorted- turn test was performed at the Seoinchon combined cycle power plant on gas turbine generator and stim turbine generator. This sensor will be used as a detecting of Inter-turn short circuits for synchronous generator's field winding.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1999년도 제14차 학술회의논문집
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• pp.281-283
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• 1999

This topic presents an inductor short turn testing. From the rudimentary principles, the quality factor(Q) decreases due to inductor short turn. Frequency response varies because of the variation of circuit inductance and resistance. In general, short turn circuit testing is performed by comparing the ratio of an inductance and resistance of inductor in that particular circuit. An alternative method can be done by considering the response of second order circuit which can give both dynamic and static testing, whereas static testing give an error results not more than 2 turns. For dynamic testing, the result is more accurate, which can test fur the short turn number form 1 turn onward.

• 한국정밀공학회지
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• 제26권5호
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• pp.87-95
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• 2009

This research introduces the efficient modeling and manufacturing method using reverse engineering combined with rotational simulation of a pair of screw and mill-turn machining realized a proposed NC program. Because previously developed model had insufficient flow measuring accuracy, we considered that matter in the aspect of method of modeling and performance test. For that reason we modified the modeling which could minimize a gab between male and female screw, and developed precise tester which consists of constant tank, flowmeter and load cell, etc., and then conducted the test for defining characteristic and accuracy of flowmeter and repeated same test 5-times. Consequently we could obtain satisfied measuring accuracy and reproducibility indicated in the catalog of master model. Hence we give our conclusion as to the validity of developing accurate screw type flowmeter using the proposed process such as reverse engineering, mill-turn machining and precise performance test.

• 한국강구조학회 논문집
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• 제23권6호
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• pp.715-724
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• 2011

인장구조 시스템에서 구조물의 하중을 지지하는 인장재 사이에 삽입되어 인장력을 조절하는 장치가 턴버클이다. 인장재가 인장구조에서 중요한 부재임에도 불구하고, 현재 인장재에 발생하는 인장력을 경제적이고 간단하게 측정하기 위한 방법이 제안되지 못하였다. 그리하여 인장구조시스템에 작용하는 인장력을 측정하기 위하여 인장력 측정장치를 개발하였다. 본 논문에서는 이론해석과 유한요소해석을 바탕으로 100kN, 200kN, 300kN급 측정한계하중을 가지는 턴버클을 실험하였다. 그 결과 이론적 해석, 유한요소해석, 실험결과는 대체로 일치하는 것으로 나타났다. 또한 유한요소해석에 의한 측정용 턴버클의 극한강도를 조사해보면, 측정한계하중의 5배 이상의 과하중에서도 충분한 안전성을 확보하고 있음을 확인할 수 있었다.

• 한국전기전자재료학회논문지
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• 제20권7호
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• pp.631-635
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• 2007

Diagnostic, surge and ac breakdown tests are widely used to evaluate the insulation condition of stator winding in traction motor. Diagnostic test included ac current, tan delta and maximum partial discharge. The result of diagnostic test indicates that five kinds of stator windings are good condition. Surge test was peformed to confirm the healthy of turn insulation in stator windings. This test is very easy to detect the turn insulation failure between normal and defect stator windings. After completing the diagnostic test, ac breakdown test has conducted gradually increasing ac voltage, until the stator winding punctured. No. 5 stator windings failed near rated voltage of 18.9 kV The breakdown voltage of No. 1 stator windings was 13.0 kV The ac breakdown voltage of normal winding is about 1.45 times higher than that of defect windings. The failure was located in a line-end coil at the exit from the core slot.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 초전도 자성체 연구회
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• pp.65-68
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• 2003

Interconnected power system operation has given rise to the problem of increased fault levels and leads to over stressing of all the components. Use have been made of recently developed high Tc superconductor in devising a superconducting fault current limiter (SFCL) that promises optimum performance in terms of capital cost, size, auto sensing, operational losses, response time and reliability. Recently, research about the application of the SFCL is actively progressing in Korea. To be applied for SFCL practically, the electrical insulation design of SFCL must be developed. Therefore, this paper presents the result of an investigation of the dielectric characteristics of turn-to-turn insulation for SFCL in liquid nitrogen. The dielectric characteristics of turn-to-turn insulation models of SFCL were investigated. We obtained following results. The breakdown voltages increased as the spacer thickness and length increased. And the breakdown voltages of turn-to-turn model without spacer were higher than the breakdown voltages of turn-to-turn model with spacer under impulse as well as AC voltages. The information gathered in this test series should be helpful in the design of liquid nitrogen filled SFCL.

• Journal of Animal Science and Technology
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• 제63권2호
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• pp.440-452
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• 2021

The purpose of this study was to determine if an 8-week therapeutic riding (TR) program was effective in improving the walking ability of students with intellectual disabilities. Thirteen students diagnosed with intellectual disabilities participated in the TR program. TR sessions were conducted twice a week (30 min per session), with a total of 16 rides taking place over an 8-week period. A gait measurement analyzer was used to measure progress based on a turn test (6-m walking and turning test), walk test (10-m walking), and timed up and go (TUG) test. Measurements were made three times: before horse-riding (P0), after 4 weeks (8 rides) of horse-riding (P1), and after 8 weeks (16 rides) of horse-riding (P2). Data analysis was conducted using SPSS software (ver. 22.0). Descriptive statistics were generated on the general characteristics of the subjects, and the Kolmogorov-Smirnov test was used to verify the normality of the data. Because of the lack of normality, the data were analyzed using a nonparametric method and the significance level was set to 0.05. Measurements of the duration of the forward gait cycle (s) in the turn test and the forward gait speed (m/s) in the walk test indicated improved walking ability after the TR program (p < 0.001); the stride length (% height) also increased significantly (p < 0.05). The walk test revealed a significant effect of the program on the duration of the forward gait cycle (p < 0.05), while there were significant improvements on the left and right of the elaborated strides (p < 0.001). No significant improvement in TUG test performance was observed after the TR program. In this study, an 8-week TR program had positive results on gait. Therefore, further research is merited, where TR programs are likely to improve the walking ability of individuals with intellectual disabilities.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기물성,응용부문
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• pp.147-148
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• 2006

Sl-Thyristor는 기존의 Power semlconductor인 단일 IGBT,MOSFET과 비교하여 높은 정격 전압과 대전류의 소호가 가능하며 빠른 turn on swithcing time을 가지는 특성이 있다. 하지만 게이트 드라이버를 이용한 Sl-Thyristor의 turn on 구동시에는 전압구동의 특성과 turn 0ff시에는 전류 구동의 특성에 가까운 구동 특성이 요구되기 때문에 스위칭 요구 특성에 맞는 게이트 드라이버의 설계 및 제어가 쉽지 않다. 본 논문은 펄스 파워 어플리케이션으로 Sl-Thyristor(PT-201 5kV/100A)를 사용하여 pulsed power moduiator용 Sl-Thyristor의 게이트 드라이버의 요구인 빠른 turn on switching 특성과 turn off 시 Si-Thyristor 내의 전하를 빨리 제거하기 위한 조건을 제시하고 있다.

• 대한교통학회지
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• 제14권3호
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• pp.45-59
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• 1996

The shortest path algorithm for route guidance is implicitly required not only to support geometrical variations of transportation network such as U-TURN or P-TURN but to efficiency search reasonable routes in searching mechanism. The purpose of this paper is to integrate such two requirements ; that is, to allow U-TURN and P-TURN possibilities and to cut down searching time in locating routes between two points (origin and destination) in networks. We also propose a new type of link searching algorithm which can solve the limitation of vine building algorithm at consecutively left-turn prohibited intersections. The test site is a block of Gangnam road network that has some left-turn prohibited and allowed U-TURN intersections. Four models have been identified to be comparatively analyzed in terms of searching efficiency. The Models are as follows : (i) Model 1 - Link Searching Dijkstra Algorithm without Searching Area Extraction (SAE) ; (ii) Model 2 - Link Searching Dijkstra Algorithm with SAE ; (iii) Model 3 - Link Searching Bidirectional Dijkstra Algorithm without SAE ; and (iv) Model 4 - Link Searching Bidirectional Dijkstra Algorithm with SAE. The results of comparative evaluation show that Model 4 can effectively find optimum path faster than any other models as expected. Some discussions and future research agenda have been presented in the light of dynamic route guidance application of the urban ATIS.