• Proceedings of the KSME Conference
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• 2004.04a
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• pp.426-431
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• 2004

Leaking water coolant into stator electrical insulation is a growing concern for the aging water-cooled generator since leaks in the generator water-cooled stator winding can affect machine availability and insulation life. But a domestic techniques of such field are insufficient and depend wholly on GE or TOSHIBA technique. Therefore this paper introduces measuring principle and developed measuring system, which has been used to detecting wet absorption. We accomplished the experiment with a stator promotion of virtue which is used in actual power plant. Also, Experimental method of generator stator winding, which is investigated into wet absorption test.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.95-97
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• 2005

Loss in the multi-stacked HTS wires are affected by a number of factor, such as, number of wires used in the stack, direction of external magnetic field and insulation thickness between the wire. This paper examines the effects of the insulation thickness on the magnetization loss of the multi-stacked YBCO coated conductor. Measurements of magnetization loss were performed using 4 different typo of multi-stacked wires and under various angle of external magnetic field. Test results show that loss density per unit volume increased for YBCO coated conductors when thickness of insulation increased. Loss density per unit volume decreased for YBCO coaled conductors when stacking number of tapes increased.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.671-674
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• 2000

A children's electric shock accidents have broken out because children can easily insert sharp things in 220V receptacle holes. As the test result of pushing force, children's pushing force was about 2-4kg and the pushing force of sharp things was less than 2kg. Therefore, it is reason for electric shock that children's pushing force is large than pushing force of sharp things. We have measured insulation resistance for the receptacles of five companies during 50 weeks in humid condition. As these results, Insulation resistance for the receptacles of J. Co. had rapidly decreased with lapse of time. As the result for investigating the surface of receptacle by SEM and EDX, Al, Fe and Br, which weren't discovered at original form, were produced. Therefore, the receptacles of J. Co. should be the improved in the quality of insulating material because insulation resistance can be decreased in humid environment

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.1
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• pp.93-101
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• 2002

In this study, the stator form-winding sample coils based on silicone resin and polyimide were made for fault prediction and reliability estimation on the C-Class(200$\^{C}$ ) insulation system of traction motors. The complex accelerative degradation was periodically performed during 10 cycles, which was composed of thermal stress, fast rising surge voltage, vibration, water immersion and overvoltage applying. After aging of 10 cycles, the condition diagnosis test such as insulation resistance '||'&'||' polarization index, capacitance '||'&'||' dielectric loss and partial discharge properties were investigated in the temperature range of 20 ∼ 160$\^{C}$. Relationship among condition diagnosis tests was analyzed to find a dominative degradation factor and an insulation state at end-life point.

• Progress in Superconductivity and Cryogenics
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• v.9 no.1
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• pp.32-36
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• 2007

The 600 kJ calss high-temperature superconducting(HTS) SMES(superconducting magnetic energy storage) system is being developed by Korean Electrotechnology Research Institute(KERI). The system is operated in cryogenic temperature and high vacuum condition. The SMES magnet was cooled by conduction cooling method using a Gifford-McMahon cycle cryocooler. Thus the electric insulation design at cryogenic temperature and high vacuum is a key and an important element. Because it accomplish compact design that is a big advantage of HTS SMES. This paper describes the electric insulation design, fabrication and experimental results for a mini model of conduction cooled HTS SMES.

• Journal of the Korea Institute of Building Construction
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• v.17 no.6
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• pp.493-498
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• 2017

This study is a pioneer investigation to enhance the insulation capacity of the conventional aerated concrete using hydrophobic aerogels. As the main test parameters, aerogel content varied from 0% to 40% of the foam volume. Test results showed that the compressive strength of aerated concrete containing aerogels was lower by 17%~34% than that of the conventional aerated concrete. In addition, the effect of the aerogels on reducing thermal conductivity of aerated concrete is insignificant because of the partial condensation and abnormal distribution of the hydrophobic aerogels. Hence, further hydrophilic treatment for the surface of aerogels is recommended to minimize the decrease in compressive strength and enhance the insulation capacity of aerated concrete.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.4
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• pp.541-545
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• 2009

This study evaluated the contact resistance, insulation resistance, withstand voltage characteristics and insertion force, etc., of the wire connector used inside an integrated LITE WAY lighting fixture developed for efficient installation. Since the connector connecting the lighting fixture's internal wires is housed, it is easily connected and separated and has a structure enabling a close-fitting connection. The temperature and time applied to the high temperature characteristics test of the connector are $105^{\circ}C$ and 16 hours, respectively. The measured contact resistance of the high temperature tested connector was 3.258 mV/A, and its measured insulation resistance was greater than $10\;G{\Omega}$ All specimens demonstrated uniform insulation characteristics, which could be seen to be in good condition. From the withstand voltage test results found before and after performing the high temperature operation test on the connector for cable connection, it was confirmed that the withstand voltage characteristics between all terminals were good. The insertion force of the connector connecting the internal wiring averaged 9.67 kgf. It was observed that the insertion force between the plug housing and the female terminal, and that between the plug housing and the male terminal, were 0.680 kgf and 1.27 kgf on average, respectively.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.17-20
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• 2008

To develop floor impact sound resilient materials of apartment house effectively, floor impact sound insulation performance test lab. was designed and constructed in T company. Introducing specification and basic performance of this lab. could be helpful in plan and design of another lab. Floor space size of this lab. is $4.2m{\times}5.5m$ and this size is similar with that of living room of usual apartment house's (about $100m^2$) and the height of lab. is 2.4m. Slab thickness is designed by 180mm. Frequency characteristics is similar to general apartment house. Reverberation time of sound receiving room displays 1.26sec in 125Hz by establishing sound-absorbing materials. For light weight impact sound insulation performance of concrete bare floor structure is estimated by $L_{i,AW}\;=\;73$ and for heavy weight is estimated by $L_{i,Fmax,AW}\;=\;50$. Sound pressure level distribution of sound receiving room is ranged very uniformly. With these results, floor impact sound resilient materials could be evaluated and the results could be trusted by comparison tests.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.11a
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• pp.25-28
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• 2005

This study investigates the field application of surface insulation curing method, which combined double layer bubble sheet(DBS) and thick-curing-material(TCM) for cold weather concreting. According to the test, deck slab, curing only upper section with DBS and TCM, does not make big different temperature history with that, curing both upper and bottom section during daily average temperature 6.5t. It is concluded that combination of DBS and TCM in only upper section can be safely cured in early period of time during cold water concreting. The field test was carried out with this favourable data. The upper deck slab was insulated by combination of DBS and TCM, and the construction was surrounded by tent. in order to protect from outside wind. The test result shows that the lowest temperature of deck slab indicated 6$ ^{circ}C $. It demonstrated that this curing method can resist early frost and save construction cost in the side of management and saving labor cost, compared with previous method. In addition, the column specimen, combined both form and bubble board, exhibited favorable temperature history, due to internal hydration heat insulation effect.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1912-1914
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• 2000

This is the first report of a series of field test result of large high voltage generator & motors. Major specimens were 6.6/13.2kV class hydroric power & pump motor that was installed and operated for public water service by KOWACO(KOrea WAter resources COperation). The capacity of specimen gene rater & motors were in range of several hundred kVA$\sim$50MVA. Until now, we get the 100 field test result by testing technique discribed in IEEE standards and Discharge map technique from Japanse manufactures. The test result was varied very wide range, and there was a tendency according to insulation material and manufacture.