• Title/Summary/Keyword: Polarity Discrimination

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A Study on the Polarity Discrimination Method of the Stator Windings for 3 Phase Induction Motors based on the Residual Magnetism and I Winding Connection (잔류자기와 I 결선에 의한 3상유도전동기 고정자 권선의 극성판별법에 대한 연구)

  • Choi, Soon-Man
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.1
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    • pp.72-77
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    • 2015
  • When connecting 6 lead wires from stator windings to the terminals of 3 phase induction motors for Y or ${\triangle}$ connection, it is feared that the polarities of windings could be reversed each other if the wire tags are lost or erased, resulting in inadmissibly high current to motors in case of starting. To protect motors against such situations, some test procedures are necessary during wire connection which need to be easy ways to electricians without particular tools except a general multi-tester and with less time-consuming in the field. This study focuses on a test measure to satisfy these requirements which is able to provide them a convenient procedure for winding polarity discrimination considering the field condition. Here, the proposed measure utilizes the residual magnetism of the rotor and checks the indication of voltage or current at windings which are induced by the residual flux of rotor when rotating it by hands with 3 stator windings connected in the form of I connection. Principle characteristics and experiment results for this method are analyzed in the view of the effectiveness and applicability for the winding polarity discrimination.

Simultaneous Chiral Discrimination of Nine Non-Steroidal Antiinflammatory Drugs by Cyclodextrin-Modified Capillary Electrophoresis in Normal and Reversed Polarity Modes

  • Kim, Ji-Yung;La, Sook-Ie;Kim, Jung-Han;Kim, Kyoung-Rae
    • Proceedings of the PSK Conference
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    • 2003.04a
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    • pp.276.2-276.2
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    • 2003
  • Simultaneous enantioseparation of nine racemic non-steroidal antiinflammatory drugs (NSAIDs) for their accurate chiral discrimination was achieved by cyclodextrin (CO) modified capillary electrophoresis in the normal polarity (NP) mode and in the reversed polarity (RP) mode. The NP mode employed neutral tri-O-methyl-${\beta}$-cyclodextrin (TM${\beta}$CD) as a selector dissolved in MES buffer (PH 6.0). (omitted)

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A study on how to discriminate the polarities of stator windings for 3 phase induction motors by using induced voltages based on residual magnetism (잔류자기 유도 기전력을 이용한 3상유도전동기 권선의 극성 판별법에 관한 연구)

  • Choi, Soon-Man
    • Journal of Advanced Marine Engineering and Technology
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    • v.38 no.9
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    • pp.1146-1149
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    • 2014
  • To discriminate polarities of stator windings for 3 phase induction motors terminal tags of which are not readable, it is possible to utilize the residual magnetic flux present at their rotors as well as to use the way based on external exciting current. The induced voltages are basically decided by parameters such as the quantity of residual flux, the rotator speed by hand force and the phase properties between stator windings. To adopt induced voltages by residual flux for polarity discrimination at sites, the measured voltages by multi-testers need to be readable in magnitude enough to discriminate winding condition with reasonable phase characteristics. This study focuses on the analysis of various connection cases in the expectation that the summing voltages induced by residual flux shall show zero in case of normal connections while the sum becomes greater indication if the connection is in wrong condition. The proposed method is applied to actual motors to disclose how effective it is for polarity discrimination at sites through comparison of output signals between normal and fault connections.

Simultaneous enantioseparation of $\beta$-blockers by chiral capillary electrophoresis in reversed polarity mode

  • Kim, Jiyung;Kim, Hang-Han;Kim, Kyoung-Rae
    • Proceedings of the PSK Conference
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    • 2003.10b
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    • pp.214.3-214.3
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    • 2003
  • The chiral separation of multiple ${\beta}$-blockers is described for their accurate chiral discrimination by chiral capillary electrophoresis (CE). The cyc1odextrin-modified CE system was operated in the reversed polarity mode. In this mode, fairly good enantiomeric resolutions were achieved. Relative migration times to internal standard under optimum conditions were characteristic of each enantiomer with good precision. Therefore, in this study, the usefulness for the chiral separation and accurate identification will be discussed.

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A study on how to discriminate the polarities of stator windings for 3 phase induction motors by using general purpose multi-testers (멀티테스터를 이용한 3상유도전동기 고정자 권선의 극성 판별법에 관한 연구)

  • Choi, Soon-Man
    • Journal of Advanced Marine Engineering and Technology
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    • v.38 no.9
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    • pp.1137-1140
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    • 2014
  • Faulty electric motors onboard vessels with anomalies in windings or poor insulation are usually repaired at land based workshops and reinstalled in place by crew hands after receiving the repaired motors. Especially for 3 phase induction motors which need Y-${\delta}$ starters with 6 lead wires, it would happen that the polarities of stator windings cannot be well distinguished if the original tags of these wires are erased or not visible clearly, resulting in subsequent damage to the repaired motor due to extreme current flow when the power is given to the motor the stator windings of which are wrongly connected in the polarity. This study proposes an easy way to make correct connection in winding polarities without failures based on the electro-magnetically induced voltages on windings when a slight DC current is supplied to a winding coil by using an analog multi-tester. The proposed method is applied to actual motors and delves into the applicability for polarity discrimination through a few measurements onboard vessels.

Polarity discrimination of stator windings for 3 phase induction motors by using DC differential signals between mutual inductive voltages (유도기전력의 차동신호를 이용한 3상유도전동기 고정자 권선의 극성판별)

  • Choi, Soon-Man
    • Journal of Advanced Marine Engineering and Technology
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    • v.38 no.9
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    • pp.1141-1145
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    • 2014
  • When the stator windings of 3 phase induction motors are in wrong condition, the mutual inductive responses between windings can be utilized for the purpose of diagnosing motors in that fault windings affect even the responses by DC excitation. Three phase induction motors are supposed to generate consistent inductive voltages at the remaining windings when exciting DC current is given to one of 3 windings, while the inconsistence of their voltages indicates the existence of disorder at electric motors. This study describes how the exciting current to one of three windings cause the other windings to create induced voltages, analyzing responses by transfer functions, and discloses whether or not the balance relation at two windings is normal in the way of measuring the differential voltage of their outputs. For experiment, common analog multi-testers is used for applying exciting current and measuring the output signal to confirm whether the proposed method is useful enough to be able to discriminate wrong polarities of windings onboard vessels including also the case of exciting current by AC.

EEG Analysis at the Moment of Yes/No Decision: Study of Spatio-Temporal Relations (긍/부정 선택 순간의 뇌파 변화 연구: 두 위치에서 측정된 뇌파의 상호관계 분석)

  • 김민준;신승철;송윤선;류창수;문성실;손진훈
    • Proceedings of the Korean Society for Emotion and Sensibility Conference
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    • 2001.05a
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    • pp.26-31
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    • 2001
  • 긍/부정 선택 실험에서 나타나는 뇌파 변화를 연구하였다. 서로 다른 위치에서 측정된 뇌파의 시공간적 상호관계를 정량화하는 변수로, 시간영역에서 계산하기 용이한 동기율(synchronization rate), 편향성(synchronization rate), 편향성(polarity), 상호상관(cross-correlation) 등의 변수를 도입하여, 긍/부정 선택 순간의 뇌파 변화를 살펴보았다. 좌우 전전두엽(Fp1, Fp2)에서 특정된 뇌파를 사용하여 계산한 동기율, 편향성의 평균과 요동폭, 상호상관 등은, 선택 순간 근처에서, 평상시에 뇌파와 통계적으로 유의미한 차이를 보였다.

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A Preliminary Study of The Singer-Loomis Type Deployment Inventory for the Korean Version (싱어 루미스 심리 유형 검사의 한국판 제작을 위한 예비연구)

  • Hyoin Park
    • Sim-seong Yeon-gu
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    • v.28 no.2
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    • pp.139-153
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    • 2013
  • Psychological typology in analytic psychology is used not only for ascertaining the attitude or function of the conscious ego, but also as one blueprint for the individuation process. We all know the need to emphasize an awareness of the deployment and development of the superior function, the secondary function, the third function and the inferior function for the individuation process. This study has the goal of refining our awareness of this deployment and development of typological functions. The questionnaires of the Myers-Briggs Type Inventory and the Gray Wheelwrights Jungian Type Survey use the method of a forced-choice questionnaire, on the assumption of a bi-polarity hypothesis. But the questionnaire of the Singer-Loomis Type Deployment Inventory uses the Likert scale. It is able to show the deployment of the superior function, the secondary function, the third function and the inferior function visibly. It allows us to test the subject at stated periods for his/her development or change of psychological typology. The Singer-Loomis Type Deployment Inventory is a statistically superior method for showing Jung's psychological typology relative to both the Myers-Briggs Type Inventory and the Gray Wheelwrights Jungian Type Survey. I have studied how the original authors of The Singer-Loomis Type Deployment Inventory understood Jung's psychological typology. I produced the reliability and the item-discrimination power of the Korean Version of the Singer-Loomis Type Deployment Inventory. On the basis of this study, I produced the revised Korean version 1 of Singer-Loomis Type Deployment Inventory.

Quantitative Electroencephalogram Markers for Predicting Cerebral Amyloid Pathology in Non-Demented Older Individuals With Depression: A Preliminary Study (비치매 노인 우울증 환자에서 대뇌 아밀로이드 병리 예측을 위한 정량화 뇌파 지표: 예비연구)

  • Park, Seon Young;Chae, Soohyun;Park, Jinsick;Lee, Dong Young;Park, Jee Eun
    • Sleep Medicine and Psychophysiology
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    • v.28 no.2
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    • pp.78-85
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    • 2021
  • Objectives: When elderly patients show depressive symptoms, discrimination between depressive disorder and prodromal phase of Alzheimer's disease is important. We tested whether a quantitative electroencephalogram (qEEG) marker was associated with cerebral amyloid-β (Aβ) deposition in older adults with depression. Methods: Non-demented older individuals (≥ 55years) diagnosed with depression were included in the analyses (n = 63; 76.2% female; mean age ± standard deviation 73.7 ± 6.87 years). The participants were divided into Aβ+ (n = 32) and Aβ- (n = 31) groups based on amyloid PET assessment. EEG was recorded during the 7min eye-closed (EC) phase and 3min eye-open (EO) phase, and all EEG data were analyzed using Fourier transform spectral analysis. We tested interaction effects among Aβ positivity, condition (EC vs. EO), laterality (left, midline, or right), and polarity (frontal, central, or posterior) for EEG alpha band power. Then, the EC-to-EO alpha reactivity index (ARI) was examined as a neurophysiological marker for predicting Aβ+ in depressed older adults. Results: The mean power spectral density of the alpha band in EO phase showed a significant difference between the Aβ+ and Aβ- groups (F = 6.258, p = 0.015). A significant 3-way interaction was observed among Aβ positivity, condition, and laterality on alpha-band power after adjusting for age, sex, educational years, global cognitive function, medication use, and white matter hyperintensities on MRI (F = 3.720, p = 0.030). However, post-hoc analyses showed no significant difference in ARI according to Aβ status in any regions of interest. Conclusion: Among older adults with depression, increased power in EO phase alpha band was associated with Aβ positivity. However, EC-to-EO ARI was not confirmed as a predictor for Aβ+ in depressed older individuals. Future studies with larger samples are needed to confirm our results.