• Title/Summary/Keyword: Eddy current

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Finite Element Analysis of a BLDC Motor Considering the Eddy Current in Rotor Steel Shell (회전자 철심의 와전류를 고려한 BLDC 전동기의 유한 요소 해석)

  • Park, Seung-Chan;Yun, Tae-Ho;Gwon, Byeong-Il;Yun, Hui-Su;Won, Seong-Hong
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.48 no.3
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    • pp.110-116
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    • 1999
  • This paper describes the effect of eddy currents in the rotor steel shell of exterior-rotor permanent magnet BLDC motor of which rotor is revolving at a high speed. A two-dimensional time-stepping finite element method is used for analyzing electromagnetic field and computing performances of the motor. As a result the effect of the eddy currents in the rotor steel shell is shown by comparing the analysis results from both the proposed method and the conventional one.

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Effects of Vertical and Lateral Motion on Levitation Magnet System (상하 및 좌우진동이 부상용 전자석 시스템에 미치는영향)

  • 차귀수;배동진
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.41 no.1
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    • pp.18-23
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    • 1992
  • Magnet core and rail of a magnetically levitated vehicle are usually made of highly conductive materials. Accordingly, eddy currents are induced in those members. Eddy currents often lead to a decrement of levitation and guidance force. This paper has calculated the decrement of both forces due to eddy current generated by magnet's vertical and lateral motion. U-shaped electromagnet and rail were chosen as amodel of 2D finite element analysis. Calculated results proved that both forces dropped significantly at high speed. Consequently, effects of eddy current should be considered in designing the magnet and control system.

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Eddy Current Analysis In Cover Plate of Power Transformers using Indirect Boundary Integral Equation Method (간접경계적분법을 이용한 변압기 cover plate에서의 와전류 해석)

  • Kim, Sang-Young;Kim, Dong-Hun;Han, Song-Yop
    • Proceedings of the KIEE Conference
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    • 1998.11a
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    • pp.88-90
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    • 1998
  • In this paper, the indirect BIEM(boundary integral equation method) is adopted to analyze 3-D eddy currents in cover plate of power transformer. In indirect BIEM, the equivalent magnetic surface charge density and the eqivalent magnanetic surface current density are the unknowns. Using triangular constant elements, the integral equations are discretized into boundary element equations of minimum order. Eddy currents are obtained in terms of euqivalent magnetic surface sources. And the locad overheating can be predicted using the eddy currents distribution in cover plate of power transformer.

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A Study on the Effect of the Contact Electrode Slits in the Vacuum Interrupter with Axial Magnetic Field Type (종자계형 진공 인터럽터에서 접점전극 슬릿의 영향에 관한 연구)

  • 하덕용;강형부;최승길;최경호
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.15 no.9
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    • pp.822-829
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    • 2002
  • This paper deals with the distribution characteristics of the current density and axial magnetic flux density for each slits made on the contact electrode in the vacuum interrupter with axial magnetic field type using 3-dimension finite element analysis. It has been known that the presence of an axial magnetic field parallel to the current flow in the arc plasma can increase the high current breaking capacity of vacuum interrupter by carrying out the arc plasma from constricted mode to diffusion mode. The axial magnetic field is created of itself by current flow in the segments of coil electrode behind the contact electrode. The analyzed results show that if the slits are made in the contact electrode, they can increase the current density and axial magnetic flux density in the contact electrode surface and at the gap distance, which is due to decrease the effect of eddy currents flowing in the contact electrode. The phase shift due to eddy currents, defined 3s time difference between the maximum value of current and axial magnetic field, is decreased still more by increasing the number of slits made in the contact electrode at the center point of gap distance. These results demonstrate that 3-dimension finite element analysis has a great deal of merits in the development and evaluation of new electrode at the design of vacuum interrupter.

Development of an Eddy Current Type Magnetic Floor Hinge

  • Lee, Kapjin;Kim, Chulsoo;Park, Kyihwan
    • 제어로봇시스템학회:학술대회논문집
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    • 2002.10a
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    • pp.118.4-118
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    • 2002
  • $\textbullet$ Magnetic floor hinge $\textbullet$ Recovering torque $\textbullet$ Eddy Currents $\textbullet$ Magnetic damper $\textbullet$ Optimal design $\textbullet$ Cost optimization

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Magnetic Substance Search Using Finite Element Method and Neural Network (유한요소법과 인공지능을 이용할 자성체 탐사)

  • Lee, Kang-Woo;Park, Il-Han
    • Proceedings of the KIEE Conference
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    • 1997.07a
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    • pp.198-200
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    • 1997
  • This paper consider a simple Nondestructive Testing(NDT) having eddy currnt effect. We analyzed the two dimension modeling of alternative magnetic field. eddy current with voltage source. And, the current magnitude and phase data obtained from each different frequency five object position is used for learning the neural network. Therefore, we can recognize an object position pattern from new input current magnitude, phase data.

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A study on the characteristics of eddy current braking torque with electromagnet exciting (전자석을 이용한 와전류 제동기의 제동 특성에 관한 연구)

  • Kim, Cherl-Jin;Lee, Kwan-Yong;Kim, Yong-Ha;Han, Kyoung-Hee;Baek, Soo-Hyun
    • Proceedings of the KIEE Conference
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    • 2002.07b
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    • pp.906-908
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    • 2002
  • The technical improvement of servo system, it is required to study on robust control method in company. It needs to study on brake system that has constant torque-speed performance as load variation. In this paper, braking torque characteristics of eddy current braker between electromagnet stator and rotating disk are analyzed. The torque-speed characteristics and proper disk construction are presented. From the computer simulation results, it was found that eddy current braking torque is linear or approximately constant over the desired speed range depending on the rotor material, disk construction, pole number and pole displacement of stator. The relationship of these parameters are confirmed by experimental result.

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Vibration Suppression of a Cantilever Beam Using MTMD (MTMD를 이용한 보의 진동 억제)

  • Bae, Jae-Sung;Hwang, Jai-Hyuk;Kim, Jong-Hyuk;Lim, Jae-Hyuk
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.12
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    • pp.1091-1097
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    • 2011
  • In the present study, TMD(tuned mass damper) with eddy current damping is proposed to suppress the vibration of a cantilever beam effectively. The advantages of TMD are that it is simple and its performance are excellent at any particular frequency. However, TMD may have the low performance at other frequency. To solve this problem and improve its performance, this study applies the eddy current damping to TMD. This TMD with ECD is named as MTMD(magnetically tuned mass damper). MTMD is designed for the vibration suppression of a cantilever beam. The mathematical modeling, simulation, and experiments of the cantilever beam with MTMD are performed. From analytic and experimental results, it can be concluded that the vibration suppression performance of MTMD are excellent.

A study on the Relationship between the Size of Defect and the Intensity of Eddy Current Signal in Heat Exchanging Tube made of STS 304. (Stainless강(鋼) 전열관(傳熱管)에 있어서 과전류(過電流) 신호강도(信號强度)와 결함(缺陷)크기와의 관계에 관한 연구(硏究))

  • Han, E.K.;Eom, H.S.;Park, I.G.;Choi, M.S.
    • Journal of the Korean Society for Nondestructive Testing
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    • v.6 no.2
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    • pp.7-16
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    • 1987
  • Eddy Current Examination is expected as the effective technique for nondestructive inspection of steam generator and various kinds of heat exchanging tubes made of STS - 304. In Case of E. C. T, a study on the various factors which have an effect on coil impedance is very important to the sensitivity of defect detection and the ratio of signal to noise. Therefore, this study analyzed coil impedance by means of the variational principle, the minimized theory of energy functional and the application of Finite Element Method. Really by using E. C. T, the relationship between the size of defects and the intensity of Eddy Current Signals can be obtained. Signal intensity becomes maximum at certain frequency. This frequency is affected by the characteristics and the position of signal sources.

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Analysis and Performance of the Self Excited Eddy Current Brake

  • Cho, Sooyoung;Jeong, Teachul;Bae, Jaenam;Yoo, Changhee;Lee, Ju
    • Journal of Electrical Engineering and Technology
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    • v.12 no.1
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    • pp.459-465
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    • 2017
  • This paper describes a performance analysis of self-excited eddy current brake(SECB). Stator winding of SECB is connected by capacitor instead of voltage source, and SECB's braking force is generated by L-C resonance. SECB has wide range of driving and nonlinear inductance as well. Therefore, it is important to select capacitance based on the value of inductance. This paper discusses about the process of deciding capacitance and the change of resonance frequency based on the inductance change in each speed. Also the braking force was confirmed by the experimental model of SECB.