• Resources Recycling
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• v.11 no.5
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• pp.34-38
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• 2002

To minimize the size of transformer volume, the operating frequency of ferrites cores increasing. The power loss of Mn-Zn ferrites comprises hysteresis loss, eddy current loss and residual loss. In the range more then 500 KHz, the total power loss is mainly due to the residual loss. The power loss increase with the frequency 3rd power. To minimize residual loss as well as eddy current loss, the microstructure should have small grain and high density, It should be noted that as the product of resonance frequency and static permeability increase, the power loss decrease at high frequency region.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2003.08a
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• pp.164-169
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• 2003

The need fur higher grid resolution in climate models is often discussed (e.g. McAvaney et al.,2001) because a number of important oceanic processes are not resolved by the current generation of coupled models, e.g., boundary currents, mesoscale eddy fluxes, sill through flows. McClean et al., (1997) and Bryan and Smith (1998) have compared simulated mesoscale variability in simulations at several eddy-resolving resolutions to TOPEX/Poseidon and similar data. (omitted)

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.820-821
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• 2008

본 논문은 FEA 기법을 이용하여 40kW급 HEV용 Traction 모터의 설계 및 고효율화를 위한 회전자 영구자석의 Eddy Current loss 저감 방안에 대한 연구를 수행하였다. 먼저 FEA 기법을 이용하여 40kW급 HEV용 Traction 모터 설계 및 특성해석을 수행하여 FEA 해석기법의 타당성을 확보하였다. 또한 Traction 모터의 손실 저감을 위해 magnet부분의 eddy current loss 저감방안에 대해 논하였으며, FEA 기법을 이용하여 회전자 magnet이 Solid, 1/2, 1/4, 1/14 segments로 나눈 타입에 따른 결과를 비교 분석하였다. 그 결과 magnet형태를 기존의 Solid 타입에서 14segments 타입으로 분할 시, magnet 내부의 current path가 줄어들어 eddy current loss가 가장 많이 저감됨을 알 수 있었으며, 이를 통해 HEV용 traction 모터의 고효율, 고성능화 설계방안을 도출 할 수 있었다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.905-908
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• 2001

The microstructure and the magnetic properties of Mn-Zn ferrite, which were power loss and saturation magnetic flux density, were investigated as the function of the process before firing. The highest initial permeability and the lowest power loss were attained to the specimen with CaO 400 ppm as a resulted from the highest solubility to SiO$_2$and the creation of liquid phase which improved sintering. The biggest grain size, the highest saturation magnetic flux density and the lowest power loss, which was resulted from that the eddy current loss increased as grain size increased but the hysteresis loss much more decreased and the hysteresis loss strongly influenced on the total power loss rather than the eddy current loss, were obtained to the Mn-Zn ferrite added 2wt% PVA. The power loss was lowest and the saturation magnetic flux density was highest in case of 1 ton/$\textrm{cm}^2$ and the grain size was not influenced.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.784-786
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• 2000

최근에 주목받고 있는 초고속 구동 전기기기의 전자기 설계에 있어서는 일반적 설계법외에 고려하여야 할 상수들이 있다. 10만 rpm급의 고속회전이 필요한 전자기 응용기기들은 물리적 접속이 불가능하며, 초고속 switching이 가능한 전력소자나 높은 주파수에서도 eddy current 및 hysterisis loss를 최소화 할 수 있는 강판 제질의 개발이 선행되어야 가능하다. 본 논문에서는 이러한 초고속 구동을 하는 전자기 응용 기기의 설계에 있어서 고려하여야 하는 유기 기전력, 풍손, 마찰손, eddy current and hysterisis loss 와 같은 철손 그리고 tooth-ripple losse 등에 대한 연구결과를 설명하며, 초고속 전자기 응용기기의 구동 특성과 초고속 회전에서 가장 우려되는 고주파 손실을 최소화하고 고효율을 유지하기 위한 최적형상 설계를 제시한다.

• Proceedings of the Korean Magnestics Society Conference
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• 2002.12a
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• pp.104-105
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• 2002

Ni$_{1-x}$-Zn$_{x}$ ferrite는 매우 큰 저항과 적은 eddy current loss를 가지고 있어 transfomer core나 radio frequency coil같은 high power device등의 전자 재료로 이용된다[1]. Ni$_{1-x}$-Zn$_{x}$ ferrite의 합성에는 여러 가지 방법이 이용되고 있으나 oxide/carbonate를 이용하여 120$0^{\circ}C$ 이상의 고온의 열을 가해 하소하는 solid-state reation과 diethylamine을 이용하여 metal nitrate를 공침 하는 coprecipition방법, sol-gel 방법 등의 wet chemical method가 가장 일반적이다[2-3]. (중략)

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.5
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• pp.320-326
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• 2000

The canned motor of 3-phase induction is used for main coolant pump(MCP). The type of motor is canned-motor that stator and rotor are welded by sealed can. So, cooling water flows in the air gap of the canned motor as an independent cycling cooling system from the air gap to yoke of the motor to prevent high temperature of stator can and to lubricate bearing. Heat exchange is occurred between cooling water in the air gap and cooling water from the exterior pump to prevent rising of temperature in the motor. I has to analyze the characteristics of can exactly because the loss and the heat in the can are very important to design MCP. Therefore, thermal analysis is studied considering the effect of eddy-current los induced in the can.