• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.187-188
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• 2006

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.52-54
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• 1999

This paper has proposed various rotor type model to analyze the performance of Reluctance motor. The simulation results show that the proposed models have not revealed performance variation.

• Proceedings of the Korean Magnestics Society Conference
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• 2017.05a
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• pp.186-186
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• 2017

• Proceedings of the Korean Magnestics Society Conference
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• 2012.05a
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• pp.136-136
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• 2012

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.3 no.1
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• pp.3-10
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• 1992

Flux-drive waveguide phase shifter is designed by twin-slab model. Measured differential phase shifts are smaller than the theoretical values by 8-9 percents. Measured insertion loss and VSWR of the phase shifter using TT73-2200 ferite are less than 0.45dB and 1.25 respectively, within pass band. The phase shifter using double-setup transformer shows wider bandwidth characteristics. Finally the reduced-height waveguide phase shifter using TT3-2900 ferrite shows very efficient suppression of higher-oreder modes.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.2
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• pp.107-115
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• 2003

PMSM(permanent magnet synchronous motor) are widely used in industrial and home appliance because of their high torque to inertia ratio, superior power density, and high efficiency For the high control performance, accurate information of rotor position Is essential. In recent, sensorless algorithms are much studied due to high cost problem of position sensor and low reliability in harsh environment. In the proposed method, a differential linkage flux is used for the estimation of rotor position. The differential magnetic field flux is calculated by the voltage equations and measured phase current without any integration and differential calculus. Instead of linkage flux calculation with differential operation, a new mathematical differential method is introduced by a-$\beta$ transformation. The proposed novel position sensorless speed control scheme is verified through experimental results.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.12
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• pp.73-81
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• 2001

The MIAB welding uses a rotating arc as its heat source and is known as an efficient method fur pipe butt welding. The arc is rotated around the weld line by the electro-magnetic force resulting from the interaction of arc current and magnetic field. The electro-magnetic force is affected by magnetic flux density, arc current, and arc length. Especially, the magnetic flux density is an important factor on arc rotation and weld quality. This paper presents a 2D finite element model for the analysis of magnetic flux density in the actual welding conditions. The magnetic flux density is mainly dependent on gap between two pipes, the position of coil from gap center, exciting current, and relative permeability. Thus, the relations between magnetic flux density and main factors were investigated through experiment and analysis. Experiments were performed for the steel pipes(48.1mm O.D and 2.0mm thickness). The analysis results of magnetic flux density reveal that it increases with increasing exciting current, increasing relative permeability, decreasing distance from gap center to coil, and decreasing gap size. It is considered that the results of this study can be used as important data on the design of coil system and MIAB welding system.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.2
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• pp.93-99
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• 1986

A longline is made of many snoods with baited hooks which are connected to mainline at constant intervals. Hauling the mainline, removing the unused baits and the hooked fish, and the arrangement of hooks are dependent on mainly manual labour as compared with mechanized other fishing gear in fishing operation. The mechanization for longline operation is needed in order to eliminate the manual handling and to shorten the labour time. The magnetic hook splitting apparatus which consists of the hook separator and the guide leading to storage magazine rail was devised for the mechanization of hauling operation. The experiments were carried out in order to measure the splitting rate of hooks in accordance with the hauling speed of mainline and magnetic flux density of splitting apparatus from February to November, 1985. The splitting rate was $94\%$ for the Alaska pollack (Theragra chalcogramma) hook and $96\%$ for the halibut (Paralichthys olivaceus) hook at the hauling speed 24 m/min and magnetic flux density 482 gauss. The unsplitting of hooks was caused by entangling snood in the mainline and low magnetic flux density. The rate is greater the faster hauling speed and the lower magnetic flux density, with an average of about $6\%$, The magnetic flux density needed to hook splitting becomes increased with the increasing hauling speed. When the practical hauling speed is from 20 to 35m/min, the magnetic flux density is needed from 400 to 850 gauss.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.4
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• pp.607-616
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• 2022

A new axial flux permanent magnet machine with soft magnetic composited cores is proposed for electric vehicle application in this paper. The windings and soft magnetic composited cores can be designed to form a very compact structure, and; thus, the torque density can be improved greatly. To obtain the a good flux concentrating ability, two toroidally wound internal stator machines are designed and analyzed, and the designed motor is with NdFeB magnet for high-performance electric vehicle application. The 3-D finite-element method is used to analyze the electromagnetic parameter and performance, for performance comparison, a commercial axial flux permanent magnet machine is used. The proposed motor reduced weight about 5.8%, produced torque higher than about 8Nm for existing motor.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.2 no.3
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• pp.17-25
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• 1991

Magnetic leakage flux which is generated from the levitation magnets, linear induction motors, and guide magnets of a MagLev(Magnetic Levitation) system is directly related to inter - system EMI, intra - system EMI, and biological effects. In this paper, the magnetic leakage flux from MagLev vechicles designed by Korea Resarch Institute of Ships & Ocean Engineering was calculated considering the various parameters which influence ma- gnetic field intensity around the MagLev system. Based on the calculated field intensity, the thickness of shielding material and shielding position for MagLev floor and side walls are calculated, taking into account the shielding effectiveness of a shield with minimum weight. For the nonuniform shielding method derived from the above procedure, the weight of a shield con- sisting of floor and side walls shielding can be reduced to more 50% than uniform shielding method.