• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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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.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.7
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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.

• Transactions on Electrical and Electronic Materials
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• v.7 no.5
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• pp.262-266
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• 2006

The insulation diagnostic test and the AC breakdown test were performed under off-line using the 3.3 kV class induction motor which have been served for 10 years. These tests were conducted in means of nondestructive and destructive test. In this paper, we compared the correlation between the nondestructive and destructive test. Furthermore we setup an experimental condition with moisture and compared the insulation characteristics between moist and dry sample. From the results of the nondestructive and destructive test, it was found that the second AC current, which is the previous step of insulation breakdown, suddenly increased at a point of around 8.5 kV. The insulation breakdown of moist sample occurred at 12-14 kV, which is 4-5 kV lower than dry sample.

• Transactions on Electrical and Electronic Materials
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• v.13 no.5
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• pp.248-251
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• 2012

In order to develop a high voltage insulation material, epoxy/micro-silica composites (EMC) and epoxy/micro-silica/nano-silica composites (EMNC) with three different particle sizes in ${\mu}m$ and one particle size in nm were prepared and their tensile and flexural tests were carried out and the data was estimated by Weibull statistical analysis. The tensile strength of the neat epoxy was 82.8 MPa and those of the EMCs were larger than that of the neat epoxy, and they were much more advanced by the addition of 10 nm sized nano-silica to the EMCs. Flexural strength showed the same tendency of the tensile strength. As the micro-particle size decreased, tensile and flexural strength increased.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05b
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• pp.57-60
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• 2001

This study describes the effect of $\tau$ -ray irradiation on the properties of insulation materials for low voltage cables in a nuclear power plant. The radiation effects were characterized by measuring OIT, FTIR, electrical properties of the irradiated specimens. As a result, they showed the decrease of OIT and the increase of chemical structural defects with the increase of $\tau$ -ray amount

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.296-297
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• 2011

A series of thermogravimetric analysis tests were conducted to predict the lifetime of the PTFE electrical insulation material. The prepared PTFE samples were heated from $25^{\circ}C$ to $700^{\circ}C$ at different heating rates. The kinetic energy of the PTFE was calculated from the logarithmic heating rate versus reciprocal temperature curves at constant conversion levels. Also, the lifetime of the PTFE for a given operating temperature can be predicted using the relationship between the activation energy and the estimated lifetime proposed by Toop.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.11
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• pp.941-946
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• 2001

The fundamental study on HTV silicone for insulation material has been performed. In order to estimate the chemical behavior of siloxane under high voltage, H-NMR, GPC and vinyl contents measurement were used. As an experimental results, after high voltage stress, the molecular weight of siloxane are increased, the vinyl contents of siloxane are decreased. The dielectric strength of vinyl group containing siloxane was lower than only methyl containing siloxane.

• Transactions on Electrical and Electronic Materials
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• v.13 no.3
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• pp.153-156
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• 2012

In order to develop electrical insulation materials, epoxy/micro-silica composite (EMC) and epoxy/micro-silica/nano-silicate composite (EMNC) were prepared, and their tensile and flexural strength, AC insulation breakdown strength and thermal conductivity and thermal expansion coefficient were compared. Nano-silicate was prepared in an epoxy matrix by our AC electric field process. All properties of the neat epoxy were improved by the addition of micro-silica, which was improved much further by the addition of nano-silicate to the EMC system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.391-394
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• 2000

EPDM/silicone blend was prepared with polyorganosiloxane compatibilizer for out-door polymer insulation used to shed. Each blend had various weight ratios, 100/0, 90/10, 70/30, 50/50, 30/70, 10/90, and 0/100 as EPDM to silicone, and electrical and tracking characteristics were studied with the method of IEC 60587. And also, tracking properties and contact angle related to UV-weathering period were studied to understand the degree of degradation of blend after 1000 h UV-weathering.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1989.06a
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• pp.43-46
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• 1989

Epoxy, noticed as a new insulation material for electrical equipments, may become an excellent cured material from the crosslink reaction with some curing agents and accelerators. The characteristics of cured epoxy is determined by the method of lattice formation according to curing method. The purpose of this paper, varing the process of lattice formation by various surrounding temperatures and heating time during the curing process, is to obtain the optimum cured condition for electrical insulation from the results of investigation on the physical and dielectric properties of cured epoxy. In this investigation, it is found that the excessive temperature and heating time brings on the growth of metamorphic methyl and the insulating properties of cured epoxy is decreased by this phenomenon. As a result, it is concluded that the optimum dielectric characteristics can be obtained when cured at a curing temperature at 14$0^{\circ}C$ for one hour.