• Journal of international Conference on Electrical Machines and Systems
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• 제1권4호
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• pp.412-418
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• 2012

Eddy current brakes are electromechanical devices used as variable mechanical loads for testing electrical machines. Accurate modeling of eddy current loss is an important t factor for optimum design of eddy brake systems. In this second part, we propose novel formulations of eddy current loss in novel claw-pole eddy brake system. The proposed model for eddy current loss in novel claw-pole eddy brake system depends on the size of the claw poles. Also, in this paper, the flux density is measured by using the magnetic circuit of the novel claw pole. The model results are compared with experimental results and they are found to be in good agreement.

• Journal of Electrical Engineering and Technology
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• 제3권3호
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• pp.379-384
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• 2008

This paper examines permanent magnet eddy current couplings and brakes. Specifically, the effect of permanent magnet magnetization patterns on the magnetic field and force production is investigated. The eddy current couplings and brakes employ high energy-product neodymium-iron-boron (NdFeB) permanent magnets that act on iron-backed copper drums to provide torque transfer from motor to load without mechanical contact. A 2-dimensional finite element modeling is performed to predict the electromagnetic behavior and the torque-speed characteristics of permanent magnet type eddy current couplings and brakes under constant speed operation.

• Journal of international Conference on Electrical Machines and Systems
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• 제1권3호
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• pp.321-329
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• 2012

Providing variable load for testing a motor in high speed conditions is usually a difficult task. The eddy current brake can be used in application of load testing of motors. This paper deals with construction of a novel claw pole eddy current brake which is employed as a load for a DC counter rotating motor (CRM). These kinds of motors have two inner and outer shafts that rotate in opposite directions simultaneously, which are particularly suitable for under water propulsion systems. The prototype 45KW eddy current brake consists of two parts. One of them is installed on the inner shaft of the 60KW DC CRM and the other one is installed on its outer shaft. The simulation and experimental results with prototype brakes are also analyzed by using MATLAB/Simulink and the operational characteristic of the brake is demonstrated as a function of the motor speed and current of the magnetic poles.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.66-72
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• 2000

Commercial eddy current dynamometers control the torque of ratating body (poer supply machine) with the field coil current being operated as a braking force. In this paper, we studied about the relation between the field coil current and the torque load of eddy current dynamometer. By the torque measuring analysis of eddy current dynamometer, it is linear relation between the brake force measured from the torque meter (e.g. load cell, strain gage or spring balance etc.) which is installed at the case of dynamometer and the multiply of shaft rpm by the square of field coil current (N$\times$Ia2). To prove the relation, it was experimented and showed that the torque operated by the rotating body can be measured with the shaft rpm and the field coil current of eddy current dynamometer. This result shows a possibility that eddy current dynamometer can measures the torque of rotating body without special torque measuring devices.

• 한국전기전자재료학회논문지
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• 제27권5호
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• pp.322-327
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• 2014

Internal corrosion of the distribution line can be detected in order to develop techniques of non-destructive inspection methods that operate only on the metal track eddy current diagnosis is possible by applying the technique investigated. Sensor for the production of a finite element method modeled by using an eddy current sensor, a distribution line by using an accelerated aging samples of sodium hydroxide was prepared. Sheathed cables for internal corrosion studies detected using an eddy current sensor is considered to be possible.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.712_713
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• 2009

This paper deals with the analysis on eddy current looses of high speed permanent magnet synchronous motor (PMSM) for turbo compressor according to voltage source driving. This paper presents analytical procedures for calculation of the eddy current losses using Poynting theorem. On the basis of the magnetic vector potential and a two-dimensional (2-D) cylindrical coordinate system, this paper derived analytical solutions of the eddy current looses using phase current analysis. The eddy current losses of each harmonic obtained by fast Fourier transform (FFT) analysis of phase current are with results obtained from finite-element method (FEM).

• 비파괴검사학회지
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• 제37권1호
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• pp.21-28
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• 2017

배열 와전류 기술은 2차원적으로 나란히 정열된 다수의 와전류 코일로 구성된 탐촉자 면적에 대하여 기계적인 이동없이 전기적으로 주사할 수 있다. 단일 코일을 사용하는 와전류 기술과 비교하여 탐촉자가 한 번의 이동으로 넓은 영역을 검사할 뿐만 아니라 데이터 해석이 용이하여 검사 속도와 신뢰성을 향상시키는 장점이 있다. 이번 연구에서는 $2{\times}16$ 코일 배열의 배열 와전류 탐촉자와 순차적으로 송수신 코일을 선택하고 송수신 모드로 동작시키는 다중화기기를 개발하였다. 이 탐촉자를 이용하여 다양한 종류의 시편을 제작하여 표면검사를 수행하고, 와전류 신호 및 C-scan을 이미지 분석을 통해 송수신 모드 배열 와전류 기술의 특성에 대해 연구하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.768-770
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• 2001

The topology optimizations of electromagnetic systems with the nonlinear and the eddy current effects are studied using the finite element method. The topology design sensitivity formulations of nonlinear magnetostatics and eddy current systems are derived using the adjoint variable method. A computer program is developed using object orient programming and applied to the topology optimization of a C-core actuator. A numerical study shows the effects of saturation and eddy current by comparing results of topology optimizations.

• 비파괴검사학회지
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• 제36권2호
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• pp.155-159
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• 2016

Eddy current testing (ECT) is an important nondestructive testing technology for the inspection of flaws in conductive materials. However, this widely used technology is not suitable for inspecting lamination when a conventional pancake coil is used because the eddy current (EC) generated by the pancake coil is parallel to the lamination and will not be perturbed. A new method using a rectangular coil placed vertical to the work piece is proposed for lamination detection. The vertical sections of the rectangular coil induce ECs that are vertical to the lamination and can be perturbed by the lamination. A parametric study of a rectangular coil by finite element analysis was performed in order to examine the capability of generating vertical EC.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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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.