• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.12
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• pp.1124-1129
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• 2008

The object of this paper is to acquire the data related to insulation evaluation of hybrid vehicle traction motors. We made a comparative analysis on Insulation Resistance (IR), Dielectric Absorption Ratio (DAR), and Polarization Index (PI) of the motor stators. The experiment was carried out according to IEEE Std. 43 and IEC 60085-1 for insulation resistance test standard of rotating machinery. Test voltage of 500 V was applied between a phase and the enclosure. The IR and the DAR of used motors were lower than those of new ones. The DAR and the PI were $0.92{\sim}1.02$ and $0.74{\sim}1.1$, respectively and the result did not meet the recommendation basis 2 for insulation level H. From the experimental results, we could prepare parameters and basis for insulation evaluation of the traction motor stator by the comparative analysis of short-time insulation resistance changes, DAR and PI.

• Transactions on Electrical and Electronic Materials
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• v.15 no.1
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• pp.7-11
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• 2014

The Polarization and Depolarization Current (PDC) measurement is an efficient and effective diagnostic technique based on time domain measurement, for evaluating the high voltage insulation condition. This paper presents a review and comparison results from several published papers on the application of the PDC method to finding the conductivity and moisture content of various types of insulators. For solid insulation, the study was focused on cable insulation, electric machine stator insulation, and paper insulator in transformer insulation with different conditions. For liquid insulation, the review and comparison was done on biodegradable and mineral transformer oils, with fresh oil condition, and aged condition. The results from previous researchers tests were complied, analyzed and discussed, to evaluate the application of the PDC method to monitor the conductivity and moisture of HV equipment insulation systems. From the review results, the PDC technique successfully gives an indication of the conductivity and moisture level of high voltage insulation.

• Journal of the Korean housing association
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• v.22 no.1
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• pp.115-122
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• 2011

This study aimed at quantifying the impact of envelope insulation on energy consumption for thermal controls in residential buildings in southern part of Korea. A series of parametric simulations for a range of R-values of walls, roof, floor, and windows were computationally conducted for a prototypical Korean detached house. Analysis revealed that the total amount of heat gain was larger than that of heat loss, while the amount of energy for cooling was smaller than that for heating due to the difference of system efficiency; the envelope heat transfer was more significant for the heat loss, thus, the increase of the envelope insulation was more effective to reduce heating load; and there were certain levels of envelope insulation after which the energy saving effect was not significant. These findings are expected to be a fundamental database for the decision of proper insulation level in Korean residential buildings.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.11
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• pp.617-623
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• 2013

This study is to draw thermal property data during long-term aging, by testing the thermal conductivity of building insulation materials in Korea. The thermal resistance of extruded insulation within 3 days from manufacture performed well over the KS Standard. After 50 to 110 days, however, the thermal performance had deteriorated to the level of the KS standard. Eventually, after 4,000 days, the insulation performance had deteriorated to about 25.4~41.8% of the initial performance. Therefore, this research will be utilized as a reference for thermal properties during long-term aging, in order to improve standards and regulations related to building insulation materials.

• KIEAE Journal
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• v.9 no.5
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• pp.63-68
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• 2009

As with the disappearance of a living room window due to the trend in apartment housing construction that prefers a larger, expanded living room, the sound insulation performance of the balcony window is becoming an important factor to determine the level of indoor noise at an apartment unit. Considering that the indoor noise inside an apartment unit is mandated by law at or below 45dB(A), the balcony window is increasingly assuming an even more important role. Sound insulation performance of the window was measured by examining differences in data involving varying angles of incidence of the sound source as obtained from the same balcony window. Also, acoustic intensity measuring was performed at and around the window to determine its sound insulation quality. Results of measuring on the sound source's angles of incidence indicated that the performance showed some differences in lower frequency ranges, though with no significance. Intensity measuring results showed that the sound insulation performance was reduced near the connection part of the window and the window frame.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.219-224
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• 2008

The purpose of this paper is to acquire the data related to insulation evaluation of hybrid vehicle traction motors. We carried out a comparative analysis on Insulation Resistance (IR) and Polarization Index (PI) of motor stators according to IEEE Std. 43 and IEC 60085-1 for insulation resistance test standard of rotating machinery. Maximum test voltage which is applied to between a phase and enclosure was set at 500 V. The IRs of the used motors were lower than those of the new ones. The PIs of the used motor were ranges from 0.74 to 1.1 and did not meet the recommendation basis 2 for insulation level H. From the experimental results, we could prepare parameters and basis for insulation evaluation of motor stators by comparative analysis of the IR and the PI.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.503-504
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• 2006

This paper describes a low-level partial discharge(PD) testing that has been accepted as a non-destructive test method on insulation performance of electronic components. A comparative PD analysis combined with the Withstand Voltage Test (WVT) specified in IEC standards is carried out on high frequency switching transformers. The analysis shows that insulation degradation of the transformers under test progresses during the WVT. To avoid insulation degradation of the specimen, PD test has to be carried out at as low voltage as possible. In this study, the PD test on the transformers is performed in ranges from 50% to 70% of the test voltage specified in the WVT by measuring apparent charges below 1 pC. From the experimental results, it is expects that the low-level PD test is applicable for electronic components as a replacement of the WVT.

• International conference on construction engineering and project management
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• 2017.10a
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• pp.89-98
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• 2017

The floor heating method generally uses a wet construction method including the installation of resilient material, lightweight foam concrete, heating piping, and finishing mortar. Such a wet construction method not only delays other internal finishing processes during curing period for two mortar pouring process, but also has a disadvantage that it is difficult to replace the floor heating layer when it deteriorated because it is integrated with the frame. Dry floor heating construction method can be a good alternative in that it can solve these defects. Conversely, when it applied to the wall structure that is vulnerable to the interlayer noise compared with the column-beam structure, the question about the heavy-impact sound(HIS) insulation performance is raised. Therefore, conventional dry floor heating method is hard to apply to the wall structure apartments. Therefore, for the purpose to improve the applicability of dry floor heating method in wall structure apartments, this study investigated the change of floor impact sound, especially HIS insulation performance which is one of the required performance for the floor structure. This study tried to examine whether the change of heavy-impact sound pressure level(SPL) shows a tendency at the significant level according to the shape and mass of the floor structure. Through filed experiments on wall structure apartment, this study confirmed that the form of the raised floor shows better HIS insulation performance than the fully-supported form. In addition, it was also confirmed that the HIS insulation performance increases with the mass on the upper part. Moreover, this study found the fact that a mass of about 30 kg/m² or more should be placed on the upper structure to reduce the heavy-impact SPL according to the bang machine measuring method. Although this study has a limit due to insufficient experiment samples, if the accuracy of this study is increased, it will contribute to the diffusion of dry floor heating by setting the HIS insulation performance target and designing the dry floor heating structure that meets the target.

• Journal of the Korean Society of Safety
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• v.7 no.4
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• pp.7-12
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• 1992

The smouldering combustibility of cellulose insulation treated with boric acid-borax-aluminium sulfate as combustion retardants are examined by cigarette ignition method and electrical cardrige heater method. The effectiveness of Aluminium sulfate as a third combustion are acceptable both smouldering resistance and flame resistance at 18% level of all examined formulation. As the proportion of Aluminium sulfate in the formulation was increased, the flame resistance of cellulose insulation was improved.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.6
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• pp.361-368
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• 2010

Due to the insulation and the air-tightness requirement in modern buildings have resulted NBS(New Building Syndrome) and SBS(Sick Building Syndrome) of IAQ problems. Therefore, energy efficient way of solving such IAQ issues are of major concern in these days and building industries. This paper introduces a method to improve thermal performance with a DI(Dynamic Insulation) concept. The characteristic of the dynamic insulation is that the lower U-value as the higher air velocity through the DI in a micro level. A thermal performance monitoring study has been conducted to show the energy impact of porous DI over the static insulation material. The results show that up to 45% could be improved in the case with DI compared to the conventional insulation.