• 한국전기전자재료학회논문지
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• 제25권10호
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• pp.786-790
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• 2012

A variety of diagnostic tests are widely applied in the field in industry to evaluate the condition of high voltage (HV) motor stator insulation. In this paper, the influence of temperature on the stator insulation diagnostic tests such as the insulation resistance, AC current, dissipation factor, and partial discharge measurements are studied and reported. The tests are performed with the HV motor stator winding temperature set between $40^{\circ}C$ to $80^{\circ}C$ in $10^{\circ}C$ intervals. It is shown that the AC current, dissipation factor, and partial discharge magnitude steadily increase with temperature, which suggests that temperature must be taken into account in the interpretation of the test results.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 춘계학술대회 논문집
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• pp.32-32
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• 2010

A epoxy/multilayered silicate nanocomposite was prepared by a new AC electric application method and micro silica particle was poured into the nanocomposite in order to prepare epoxy/micro-and-nano- mixed composites (EMNC). Electric insulation breakdown strength was measured in a sphere-sphere electrode system designed for the prevention of edge breakdown and the data were estimated by Weibull plot. As the exfoliated silicate nano-plates were homogeniously dispersed in the micro silica particles, the insulation property was higherd.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.207-208
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• 2007

Epoxy resin insulators show a lot of advantages for electrical power apparatus. Because epoxy resin provide electrical and mechanical characteristic which is excellent, it is desirable to apply epoxy resin as a spacer and post insulation in Gas Insulated Switchgear (GIS). In this study, we have investigated the influence of surface electric field attached particle contaminated spacer surfaces under SF6 gas. Also, we performed analysis of electric field. As a result, when the particle was attached on spacer, we found out a surface electric field of characteristics.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.336-338
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• 2006

Diagnostic tests are used to evaluate the insulation condition of stator windings in traction motor. These tests included ac current, tan delta and maximum partial discharge. The insulation condition of stator windings was assessed by three test items. The stator windings of traction motor were m good condition. After completing the diagnostic tests, the stator windings of traction motors were subjected to gradually increasing ac voltage, until the insulation punctured. No.5 stator windings failed near rated voltage of 18.9 kV. The breakdown voltage of No.1 stator windings was 13.0. The failure was located m a line-end coil at the exit from the core slot.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.210-211
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• 2006

This study presents the technology and application of hybrid insulation film for electric magnet wire. In order to make the high efficient motor with high space factor, it is necessary to develop a self-lubrication heat-resistant insulation film that can be used when the space factor 70% or more. A key to achieving high windability is to increase the lubricity and bonding strength of vanish, which for a magnet wire generally determines the mechanical scratches characteristics. Effective ways to reduce scratches include improving insulation film prepared by organic and inorganic hybrid synthesis methods.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 E
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• pp.1614-1616
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• 1998

Insulation performance of major components of prefabricated joint such as epoxy insulation unit and premolded rubber cone are guaranteed by material selection design and proper manufacturing. On the other hand insulation performance of the interfaces between the premolded rubber cone and the epoxy insulation unit and the cable insulation is maintained by keeping the premolded rubber cone to close contact with such insulation by spring. Electric characteristics of a interface depend on the contact pressure, but the required characteristics are assured so far as a proper contact pressure is maintained. In this report, the interfacial pressure by pressure sensors both in the early stage and after heating cycle were measured and the simulation by FEM program were presented. The comparison of these two results show that interfacial pressure could be controlled optimally by changing the spring length and lubricant state of the interface.

• 전기학회논문지
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• 제65권10호
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• pp.1688-1693
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• 2016

In this study shall investigate the influence upon the electrical property of transformer oil due to the heat among accelerated heat degradation experiment for a constant hour in the typical insulation oils of mineral base oil, silicon base oil and vegetable oil. In addition, the electric insulation performance of insulation materials in transformer shall be evaluated through the electric property analysis according to the heat degradation of epoxy insulation material, which has been used for electric facilities such as a molded transformer.

• 한국전기전자재료학회논문지
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• 제28권6호
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• pp.390-395
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• 2015

Molded insulation materials are widely used from large electric power transformer apparatus to small electrical machinery and apparatus. In this study, by adding MgO with the average particle of several tens nm and the excellent thermal conductivity into molding material, we improved the problem of insulation breakdown strength decrease according to rising temperature in overload or in bad environmental condition. We confirmed the life evaluation by using the insulation breakdown and inverse involution to investigate the electrical characteristics of nano-composites materials. By using a scanning electron microscope, it is confirmed that MgO power with the average particle size of several tens nm is distributed and the filler particles is uniformly distributed in the cross section of specimens. And it is confirmed that the insulation breakdown strength of Virgin specimens is rapidly decreased at the high temperature area. But it is confirmed that the insulation breakdown strength of specimens added MgO slow decreased by thermal properties in the high temperature area improved by the contribution of the heat radiation of MgO and the suppression of tree. The results of life prediction using inverse involution, it is confirmed that the life of nano-composites is improved by contribution of MgO according to the predicted insulation breakdown strength after 10 years of specimens added 5.0 wt% of MgO is increased about 2.9 times at RT, and 4.9 times at $100^{\circ}C$ than Virgin specimen, respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.98-98
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• 2010

A epoxy/multilayered silicate nanocomposite was prepared by a new AC electric application method and micro silica particle was poured into the nanocomposite in order to prepare epoxy/micro-and-nano- mixed composites (EMNC). Electric insulation breakdown strength was measured in a sphere-sphere electrode system designed for the prevention of edge breakdown and the data were estimated by Weibull plot. As the exfoliated silicate nano-plates were homogeniously dispersed in the micro silica particles, the insulation property was higher.

• 한국전기전자재료학회논문지
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• 제23권6호
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• pp.464-470
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• 2010

A new method for the poling of piezoelectric ceramics with an air insulation medium in stead of silicon oil is described. A similar variation of electromechanical coupling coefficient $K_t$, for an air medium is observed in comparison to that of the material poled by the conventional poling method using a silicon oil medium. Different poling parameters such as dielectric constant $\varepsilon^T$ and frequency deviation ${\Delta}f$ are studied as well as the influence on the aging effect. The required poling factors to achieve the optimal piezoelectric characteristics are electric field, 2 kV/mm, temperature $100^{\circ}C$, and poling time 30 Min. From this result electric field 3 kV/mm atmosphere airs there being will be able to use with the polarization insulation medium about the piezoelectric material, confirmed.