• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.2014-2015
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• 2007

This paper deals with design and analysis of thrust magnetic bearing. Using the solutions obtained from equivalent magnetic circuit, we predict the electromagnetic characteristics such as thrust, time constant and power loss according to design parameters. And then, using non-linear finite element analysis, a detailed design is performed considering saturation in order to meet requirements.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.5
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• pp.205-213
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• 2001

This paper presents a virtual instrumentation(VI) system for LIMs performance on-line monitoring. The VI is designed using the graphical programming language LabVIEW and is capable of performing on-line measurement functions, including data acquisition, display, and analyses in the time and frequency domains, as well as data archiving. To monitor in real time the steady-state and transient electromagnetic thrust of LIMs, the search coil is used for the determination of the flux linkage components, which is then multiplied by the appropriate current components to yield a signal proportional to the electromagnetic thrust. This paper reports the LIM's dynamics measured by the proposed on-line monitoring system.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.12-14
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• 1999

Recently, the electromagnetic proportional valve has been widely used in order to control pressure and flow in such systems as NC machine and automatic facility. The linear electromagnetic solenoid used for proportional control valve ought to have hysteresis characteristic because of control the thrust force proportionably by input current. Therefore, in this study, we analysis the thrust force characteristics and established design for practical use, which allows Linear Pulse Motor(LPM) to be used as a driving system for electromagnetic proportional control valves.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.129-131
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• 2005

This paper deals with an electromagnetic analysis and control parameter estimation of a moving-coil linear oscillatory actuator (MCLOA). Analytical solutions for electromagnetic characteristics of the MCLOA are obtained from transfer relations derived in terms of a magnetic vector potential and two-dimensional (2-d) rectangular coordinate systems. And then, on the basis of 2-d analytical solutions, control parameters such as the thrust constant, the back-emf constant and winding inductances are estimated. Finally, analytical results for both electromagnetic characteristics and control parameters of the MCLOA are validated extensively by finite element (FE) analyses. In particular, test results such as static thrust, resistance and inductance measurements are given to confirm the analyses.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.294-299
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• 2004

An assessment of a novel laser-electric hybrid propulsion system was conducted, in which a laser-induced plasma was induced through laser beam irradiation onto a solid target and accelerated by electrical means instead of direct acceleration only by using a laser beam. A fundamental study of newly developed rectangular laser-assisted pulsed-plasma thruster (PPT) was conducted. On discharge characteristics and thrust performances with increased peak current compared to our previous study to increase effects of electromagnetic forces on plasma acceleration. Maximum peak current increased for our early study by increasing electromagnetic effects in a laser assisted PPT. At 8.65 J discharge energy, the maximum current reached about 8000 A. Plasma behaviors emitted from a thruster in various cases were observed with an ICCD camera. It was shown that the plasma behaviors were almost identical between low and high voltage cases in initial several hundred nanoseconds, however, plasma emission with longer duration was observed in higher voltage cases. Canted current sheet structures were also observed in the higher voltage cases using a larger capacitor. With a newly developed torsion-balance type thrust stand, thrust performances of laser assisted PPT could be estimated. The impulse bit and specific impulse linearly increased. On the other hand, coupling coefficient and the thrust efficiency did not increase linearly. The coupling coefficient decreased with energy showing maximum value (20.8 ？Nsec/J) at 0 J, or in a pure laser ablation cases. Thrust efficiency first decreased with energy from 0 to 1.4 J and then increased linearly with energy from 1.4 J to 8.6 J. At 8.65 J operation, impulse bit of 38.1 ？Nsec, specific impulse of 3791 sec, thrust efficiency of 8 %, and coupling coefficient of 4.3 ？Nsec/J were obtained.

• Journal of Electrical Engineering and Technology
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• v.2 no.2
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• pp.221-230
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• 2007

This paper deals with analytical prediction for electromagnetic characteristics of a tubular linear actuator with Halbach array using transfer relations, namely, Melcher's methodology. Using transfer relations derived in terms of magnetic vector potential and a two-dimensional (2-d) cylindrical coordinate system, this paper derives analytical solutions for magnetic vector potential due to permanent magnets (PMs) and stator winding currents. On the basis of these analytical solutions, this paper also achieves analytical solutions for the magnetic fields distribution produced by PMs, stator windings current and axial thrust. The analytical results are validated extensively by finite element (FE) analyses. In particular, test results such as thrust measurements are given to confirm the analysis. Finally, this paper estimates control parameters using analytical solutions and test results such as thrust, back-emf, inductance and resistance measurements.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.9
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• pp.82-89
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• 2002

There is an intensifying demand fur linear motors in vast range of industry applications such as in factory automation and semi-conductor manufacturing equipment due to their high positioning accuracy, high static stiffness, high thrust and excellent dynamic characteristics. This paper presents an iron core type linear motor for machine tool whose rated thrust is up to 6000N. For electromagnetic field and dynamic analysis, finite element method (FEM) is implemented to predict motor performance. Various design parameters are considered to reduce thrust ripple and to improve dynamic performance with the least sacrifice of effective thrust. Experimental results on thrust and static stiffness are also followed to confirmed the validity of the analysis.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.758-759
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• 2008

This paper presents a design of the electromagnetic pump with an tubular type linear induction motor(TLIM). The TLIM was designed for the fluid system, flow rate $15[{\ell}/min]$, and the thrust 39[N] at 0.29[m/s]. The TLIM is compared measurement with analysis. The electromagnetic pump of flow characteristics are calculated by treating TLIM thrust as a source term in the Navier-Stokes equation. The numerical analysis of flow characteristics of the liquid metal is presented for the various condition and discussed.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.11
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• pp.564-571
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• 2006

In this paper, the estimation of Z-axis thrust ripple and vibration of BLDC motor with asymmetrical permanent magnet overhang is performed by 3-D Finite Element Method (3-D FEM) and vibration experimentation. The ripple of Z-axis thrust is due to armature reaction field in BLDC motor driven to squire wave. That is generating to Z-axis vibration. The analysis results of Z-axis thrust and the vibration by Z-axis thrust ripple is validated by comparison with experimental result.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.12
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• pp.130-141
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• 2008

This paper presents the flow characteristics in the fluid circulation loop using the tubular type linear induction motor(TLIM) electromagnetic pump. A TLIM of thrust 40[N] is analyzed using the equivalent and genetic algorithm for the system The flow characteristics are analyzed by coupling the Maxwell equations with the Navier-Stokes equation with the thrust. The analysis algorithm is developed for analyzing the liquid metal flow in the system for laminar and turbulent flow. And the effect of thrust is analyzed for the flow characteristics.