• Title/Summary/Keyword: resin impregnation

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VPI Varnishing Technology Effects on Frequency Characteristics of an Air Core Inductor Used in LISN Circuit Application

  • Kanzi, Khalil;Kanzi, Majid;Nafissi, Hamidreza
    • Journal of international Conference on Electrical Machines and Systems
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    • v.2 no.1
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    • pp.57-64
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    • 2013
  • The functional characteristic of LISN circuit, which is used for measurements of conductive noise in mains power line, is basically related to frequency characteristics of passive elements like inductors used in the circuit as well as the frequency response of inductors is highly related to the resins used in the varnishing process. The significant problem in determination of an inductor's frequency characteristic is the intrinsic resistance, inductance and parasitic capacitance. In this triplet, the parasitic capacitance is the major limiting factor of inductor's frequency range. This capacitance depends on inductor design parameters and materials filling the spaces of coil like resin and its coherency after curing process. In this paper, two similar inductors were designed and built. The first inductor was not varnished while the second one was varnished with VPI technology. VPI, or Vacuum, Pressure, Impregnation technology is one of the most reliable methods performing good insulating conditions for electrical circuits and windings based on resins. The measured results show that implying varnishing technology does not significantly affect the frequency response. However, due to mechanical solidity aspects and improved environmental protection, it is better to varnish the inductors.

Electrical Properties of Woodceramics with Sending an Electric Current (통전한 우드세라믹의 전기적 성질)

  • Oh, Seung Won
    • Journal of the Korean Wood Science and Technology
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    • v.35 no.4
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    • pp.9-13
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    • 2007
  • Using sawdust boards made of pine by differing the percentage of resin impregnation, wood-ceramics were manufactured by carbonizing temperature at $650^{\circ}C$. Their electrical properties and surface temperature were measured by sending an electric current. As electrical resistance of woodceramic was lower, its surface temperature, even in a low voltage, became higher. It seemed to be necessary to applying higher voltage to the woodceramic to raise the surface temperature by target temperature $70^{\circ}C$ or more in this study, according as resistance increased. When the voltage increased, woodceramics showed higher level all in electric current, electric power and surface temperature. Arrival time, electric current and electric power increased with increase of target temperature under constant voltage.

The Insulation Test of Varnish (바니쉬의 절연성 평가)

  • Kim, Jeong-Hun;Shin, Beak-Chul;Kim, Sung-Pil;Lee, Soo-Woon;Lee, Jong-Pil;Hong, Jin-Woong
    • Proceedings of the KIEE Conference
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    • 1999.11d
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    • pp.950-952
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    • 1999
  • In this paper, we are studied a electrical properties study with P.D.GEORGE/STER LING Co. P.B 302-LV-2 POLYBUTADIENE RESIN which is used for VPI(Vacuum Pressure Impregnation)processing of field magnet and armature of traction motor in Korean national railroad at present was carried out its FT-IR (Fourier Transform Infra-Red) volume resistivity characteristics. The varnishes were experimented with the temperature range form $25[^{\circ}C]$ to $180[^{\circ}C]$ and applied voltage were supplied at 100, 250, 500, 1,000[V]. In this condition, the volume resistivity for specimens were measured. From the above study, the following data obtained for volume resistivity. It can be confirmed that velume resistivity with the increase of temperature is lower rapidly from room temperature to $130[^{\circ}C]$, and it is lower slowly at temperature higher than $130[^{\circ}C]$. Volume resistivity value is higher, according as the specimen is thick gradually. As the applied voltage is higher in the same temperature, volume resistivity value is lower.

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Cure Cycle for Thick Glass/Polyester Composites (두꺼운 유리섬유/폴리에스터 복합재료를 위한 경화 사이클)

  • 김형근;오제훈;이대길
    • Composites Research
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    • v.14 no.2
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    • pp.33-42
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    • 2001
  • The cure kinetic equation fur 52-glass/polyester prepreg composites was established through DSC (differential scanning calorimetry). Using the established kinetic equation, the temperature distribution of the thick composite was calculated considering the change of heat transfer resistance due to resin impregnation of bleeder plies used. In order to reduce the overheat during cure of thick glass fiber composites, the cure cycle was modified by introducing the cooling and reheating steps. Then the thick glass composites were cured both by the conventional cycle without any cooling or reheating step and the modified cure cycle. The mechanical properties of the thick composites cured by the both cycles were tested by the short beam shear test and the Barcol hardness test, and then their results were compared.

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The Trapped Field Characteristics of YBCO Superconductor Composite in Terms of Applied Magnetic Field (인가 자기장에 의한 YBCO 초전도체 복합체의 포획 자기장 특성)

  • Lee, M.S.;Jang, G.E.;Choi, Y.S.;Jun, B.H.;Han, Y.H.;Park, B.J.
    • Progress in Superconductivity
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    • v.12 no.1
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    • pp.12-16
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    • 2010
  • We have measured the trapped field of YBCO bulk with different configuration by applying the magnetic field of $Nb_3Sn$ superconducting magnet. Initially the circular type of YBCO bulk superconductor was prepared and then hole, parallel to the c-axis and located at the center of bulk was mechanically drilled. The YBCO bulk with hole was filled with resin. Typical size of hole in YBCO bulk was 10 mm in diameter. Trapped field characteristics were compared with different specimen conditions. Our preliminary result indicates the increment rate of trapped field, 0.232 kG, measured on the YBCO without hole was much higher than that, 0.011 kG, measured on YBCO with hole.

Performance Evaluation of C/SiC Composites (C/SiC 복합재료의 내열성능 평가)

  • Kim, Yun-Chul
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2007.04a
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    • pp.185-188
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    • 2007
  • The main objective of this research effort was to develope the performance of C/SiC composites manufactured by LSI (Liquid Silicon Infiltration) method for solid and liquid rocket propulsion system and ensure the performance analysis technique. The various carbon preform were manufactured by filament winding, tape rolling, involute layup and stack molding process. For the best performance of thermal and mechanical properties, many process conditions were tested and selected by varying preform, the content of SiC, temperature, impregnation resin and chemical vapour reaction. In conclusion, the high performance and reliability of C/SiC composite were proved for solid and liquid rocket propulsion system. And the performance analysis technique related to mathematical ablation model was originated.

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End Bearing Capacity of a Single Pile in Cohesionless Soils using Cavity Expansion Concept (공동확장개념에 의한 사질토에서의 말뚝의 선단지지각 해석)

  • 이명환
    • Geotechnical Engineering
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    • v.5 no.1
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    • pp.35-46
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    • 1989
  • To analyse the end bearing capacity of a single pile in cohesionless soils, the mode of deformation due to a pile penetration has been intestigated through model pile penetration tests using acetone hardening and resin impregnation technique. A new mode of deformation has been assumed from the experimental results and a new solution compeying with the theory of spherical cal.its expansion has been proposed. The end bearing capacity according to the proposed solution is expressed as the product of the limit spherical cavity expansion pressure multiplied by a col.relation factor. The results has been compared with other solutions based on the theory of cavity expansion. From the comparison, the proposed solution is expected to provide a way to solve the problem of pile bearing capacity prediction based on the theory of cavity expansion which often has been criticized as giving higher value of pile bearing capacity than the actual value.

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Properties and Manufacture of High Density Woodceramics by Re-carbonization - Effect of Carbonization Temperature - (재 탄화에 의한 고밀도 우드세라믹 제조 및 성질 - 탄화온도의 영향 -)

  • Oh, Seung Won;Hwang, Jung Woo
    • Journal of the Korean Wood Science and Technology
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    • v.37 no.6
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    • pp.517-523
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    • 2009
  • Repeated impregnation and carbonization processes were performed to prepare high-density woodceramics using a sawdust board. The physical properties were investigated to confirm morphological and structural changes of one-time and two-time phenolic resin-treated and carbonized woodceramics. As comparing between one-time and two-time carbonized woodceramics, the weight and the density of the two-time carbonized woodceramics decreased with an increase of the carbonization temperature. When the carbonization temperature was $600^{\circ}C$, the weight increased by 21.7% and density increased by 20.6% from $0.68g/cm^3$ to $0.82g/cm^3$, respectively, as a maximum value.

A Study on the Production of Carbon Fiber Composites using Injection-molding Grade Thermoplastic Pellets (사출성형용 열가소성 펠렛을 이용한 탄소섬유 복합소재 제작에 관한 연구)

  • Jeong, E.C.;Yoon, K.H.;Kim, J.S.;Lee, S.H.
    • Transactions of Materials Processing
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    • v.25 no.6
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    • pp.402-408
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    • 2016
  • A manufacturing technology of carbon fiber composites with thermoplastic polymer pellets and continuous woven fiber was investigated using a compression molding process. To secure the impregnation of resin into the porosity of fabric the composite specimens were prepared with general injection-molding grade polypropylene pellets and low viscosity polycarbonate pellets. Tensile tests of polypropylene and polycarbonate composites were performed. Polycarbonate composites showed higher fracture strength than that of polypropylene composites because of the difference of matrix properties. However, the increase rate of strength was lower than that of polypropylene composites due to the difference of coherence between matrix and reinforcement. To investigate the effect of carbon fiber volume fraction on the fracture strength variation polypropylene composites with different volume fraction were compression molded and tensile tests were performed together. It was shown that the fracture strength of the polypropylene composites increased by 3.2, 5.4 and 6.9 times with the increase of carbon fabric volume fraction of 0.256, 0.367, and 0.480, respectively.

Carbon Composite Material Using Nickel Nano-Powder Impregnation Research on Electromagnetic Shielding Effect (니켈나노파우더 함침기법을 이용한 탄소복합소재의 전자파차폐 효과에 관한 연구)

  • Seo, Kwang-Su;Kwac, Lee-Ku
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.19 no.12
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    • pp.49-55
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    • 2020
  • In order to improve the electromagnetic shielding rate of Carbon Fiber (CF), it was produced using the nickel nano-powder impregnating method. Using two types of nickel powder having thicknesses of 50 ㎛ and 100 ㎛, and a thermoplastic elastomer resin, a compound containing 10-20% nickel content was mixed and then manufactured through an extruder. The CF coated with the compound was woven and manufactured using a 1-ply specimen. The final nickel content of the specimen was verified using TGA and the distribution of nickel powder on the CF surface was verified using SEM. The metal shows a high shielding rate in the low-frequency band, but the shielding rate decreases at higher-frequency bands. The CF improves at the higher frequency band, and metals reflect electromagnetic waves while carbon absorbs electromagnetic waves. The study of shielding materials, which are stronger and lighter than metal, by using CF lighter than metal and enabling the shielding rate from low-frequency band to high-frequency band, confirmed that the larger the area coated with nickel nano-powder, the better the electromagnetic shielding performance. In particular, CF coated with a thickness of 100 ㎛ has a shielding rate similar to that of copper and can also be used for EV/HEV automotive cables and other applications in the future.