Ansan, South Korea
Ansan, South Korea

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Kweon D.,Korea Electric Power Research Institute | Koo K.,Korea Electric Power Research Institute | Woo J.,Korea Electric Power Research Institute | Kim Y.,Iljin Electrical Co.
IEEE Transactions on Dielectrics and Electrical Insulation | Year: 2012

This paper deals with the hot spot temperature of a transformer when filled with mineral oil, and later on, with natural ester fluid. 14 optical fiber sensors were installed in the 154 kV, 15 MVA transformer filled with mineral oil, with the hot spot temperature measured during the heat run tests. The transformer was retrofilled with natural ester fluid, after which the hot spot temperatures were measured again. For the rated power, the hottest spot temperature was 105.9 °C when the transformer was filled with mineral oil and 129.4 °C when it was filled with natural ester fluid. The hot spot temperature increased by 23.5 °C in the transformer filled with natural ester fluid. This paper applies the hot spot temperature measured using optical fiber sensors to the life curve in natural ester by McShane et al. The life curve of the thermally upgraded kraft paper in natural ester fluid was compared with that in mineral oil, as suggested by the IEEE guide. The life of the transformer filled with natural ester fluid was similar to that filled with mineral oil. Therefore, transformers filled with natural ester fluid do not require increase of cooling pump capacity and surface area of the radiator or reduction of the load to obtain the same life as that of the mineral oil. © 2012 IEEE.


Jung H.,Seoul National University | Kim Y.-U.,Samsung | Sung M.-S.,Samsung | Sung M.-S.,Iljin Electrical Co. | And 4 more authors.
Journal of Materials Chemistry | Year: 2011

A nanosize Si embedded in super-elastic Nitinol alloy matrix composite was synthesized in large-scale using arc melting followed by a rapid quenching method. Both X-ray diffraction and high resolution transmission electron microscope with energy dispersive spectroscopy analyses confirmed that approximately 50 nm Si crystallites were surrounded by the Ni-Ti matrix. Ex situ synchrotron XRD was performed to elucidate the phase transition of active materials during lithiation and delithiation. The local structural changes of the Ni-Ti inactive matrix during cycling were investigated by ex situ X-ray absorption spectroscopy analyses. This anode material showed an excellent electrochemical stability since the elastic behavior of the inactive Nitinol matrix absorbed the stress generated due to the volume expansion during lithiation of the nanosized Si embedded. © 2011 The Royal Society of Chemistry.


Kim J.-H.,Inha University | Ahn H.-J.,Iljin Electrical Co. | Kim K.-Y.,Inha University
Science China Technological Sciences | Year: 2010

High-efficiency design of a mixed-flow pump has been carried out based on numerical analysis of a three-dimensional viscous flow. For analysis, the Reynolds-averaged Navier-Stokes equations with a shear stress transport turbulence model were discretized by finite-volume approximations. Structured grid system was constructed in the computational domain, which has O-type grids near the blade surfaces and H/J-type grids in other regions. The numerical results were validated with experimental data for the heads and hydraulic efficiencies at different flow coefficients. The hydraulic efficiency at the design flow coefficient was evaluated with variation of the geometric variables, i.e., the area of the discharge and length of the vane in the diffuser. The result has shown that the hydraulic efficiency of a mixed-flow pump at the design condition is improved by the modification of the geometry. © 2010 Science in China Press and Springer Berlin Heidelberg.


Patent
ILJIN Electrical CO. | Date: 2014-12-09

A negative electrode active material for a lithium secondary battery according to an exemplary embodiment of the present invention includes an alloy containing silicon (Si), titanium (Ti), and iron (Fe), wherein the degree of amorphization of the alloy is raised by 40% or more by further adding copper (Cu) to the alloy.


Patent
ILJIN Electrical CO. | Date: 2014-12-09

A negative plate for a lithium secondary battery according to an exemplary embodiment of the present invention includes: a negative active material including a silicon (Si) alloy; a binder; and a single-walled carbon nano tube (SWCNT) dispersion liquid, the ratio of the SWCNT dispersion liquid to the silicon (Si) alloy included in the negative plate for the lithium secondary battery is 800:3 to 20:1.


Patent
ILJIN Electrical CO. | Date: 2014-12-09

A negative electrode active material for a lithium secondary battery according to an exemplary embodiment of the present invention includes: silicon (Si) of 40 to 60 at %; and an alloy including copper (Cu) and aluminum (Al), in which a ratio of the aluminum (Al) to the copper (Cu) included in the alloy is 30:70 to 65:35, and the silicon (Si) does not substantially form an intermetallic compound within the alloy.


Patent
ILJIN Electrical CO. | Date: 2014-09-20

Disclosed is a furnace transformer, which is capable of preventing induction heating by using an integrated insulating plate and paramagnetic shield plate. The furnace transformer, in which bushings of a plurality of phases is drawn out to the outside, includes an insulating plate configuring a partial surface of an external side of the furnace transformer, and all of the bushings of the plurality of phases are installed while passing through the insulating plate. According to the furnace transformer according to the present invention may maximally suppress induction heating generated on a surface of a tank adjacent to a secondary side and minimize an overall size of the furnace transformer.


Patent
IL Jin Electrical Co. | Date: 2013-06-05

The present invention relates to a negative electrode active material and a secondary battery. In the present invention, the negative electrode active material maintaining excellent cell efficiency and lifespan while showing high-capacity properties, and the secondary battery using the negative electrode may be provided.


Patent
ILJIN Electrical CO. | Date: 2015-02-10

A negative electrode active material for a lithium secondary battery according to an exemplary embodiment of the present invention includes an alloy including silicon (Si), copper (cu), and aluminum (Al) of 40 to 70 at %, wherein the ratio of aluminum (Al) to copper (Cu) included in the alloy is substantailly 10:90 to 30:70, and the alloy further includes iron (Fe), and further includes zirconium (Zr) or titanium (Ti).


The present invention provides a negative active material for a secondary battery with an improved expansion rate, which is formed by a formula below, and in which an expansion rate of the negative active material after 50 cycles is 70 to 150%, and an amorphization degree on a matrix within an alloy has a range of 25% or more, and Si has a range of 60 to 70%, Ti has a range of 9 to 14%, Fe has a range of 9 to 14%, and Al has a range larger than 1% and less than 20%. Formula: Si_(x)Ti_(y)Fe_(z)Al_(u )(x, y, z, and u are at %, x: 1(y+z+u))

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