• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.2
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• pp.301-308
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• 2011

This paper deals with the coupled electromagnetic-mechanical field analysis for short-circuit electromagnetic force of the dry-type transformer. The short-circuit currents are calculated using external circuit in accordance with short-circuit test equipment. According to short-circuit current, the generated magnetic leakage flux density in dry-type transformer model is calculated by finite element method. The radially-directed electromagnetic forces in windings are calculated using electromagnetic field analysis and then axially-directed electromagnetic forces in windings are calculated using electromagnetic-mechanical field analysis. The calculated axially-directed electromagnetic forces in high voltage winding are compared to those of measured ones and showed good agreement with experimental results.

• Nuclear Engineering and Technology
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• v.50 no.6
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• pp.869-876
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• 2018

The force of a direct current (DC) electromagnetic pump used to transport liquid lithium was analyzed to optimize its geometrical and electrical parameters by numerical simulation. In a heavy-ion accelerator, which is being developed in Korea, a liquid lithium film is utilized for its high charge-stripping efficiency for heavy ions of uranium. A DC electromagnetic pump with a flow rate of $6cm^3/s$ and a developed pressure of 1.5 MPa at a temperature of $200^{\circ}C$ was required to circulate the liquid lithium to form liquid lithium films. The current and magnetic flux densities in the flow gap, where a $Sm_2Co_{17}$ permanent magnet was used to generate a magnetic field, were analyzed for the electromagnetic force distribution generated in the pump. The pressure developed by the Lorentz force on the electromagnetic force was calculated by considering the electromotive force and hydraulic pressure drop in the narrow flow channel. The opposite force at the end part due to the magnetic flux density in the opposite direction depended on the pump geometrical parameters such as the pump duct length and width that defines the rectangular channels in the nonhomogeneous distributions of the current and magnetic fields.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.2
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• pp.147-152
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• 1999

Semiconductor piezoresistive type vibration sensor was fabricated by using semiconductor process and micromachining technology. To measure the micro electromagnetic force between coil and magnet, fabricated vibration sensor was used. Toapply micro electromagnetic force produced from the micro exciter, small-sized NdFeB permanent magnet was attached on the mass of the fabricated vibration sensor. The measured electromagnetic force are about 5~180dyne when the applied sinusoidal current of 1KHz in the range of 1.5~8mA. The measurement of micro electromagnetic forcewas performed by changing the distance between coil and magnet. Output characteristics of micro electromagnetic force according to the applied coil current were linear. Furthermore, output results were used to get the transfer constant that is important to decide the efficiency and the performance of the coil and magnet.

• Journal of Magnetics
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• v.21 no.2
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• pp.215-221
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• 2016

We conducted a phased electromagnetic forming process analysis (EFPA) over time through a coupling of electromagnetic analysis and structural analysis. The analysis is conducted through a direct linkage between electromagnetic analysis and structural analysis. The analysis process is repeated until the electric current is completely discharged by a formed coil. We calculate the forming force that affects the workpiece using MAXWELL, a commercial electromagnetic finite element analysis program. Then, we simulate plastic behavior by using the calculated forming force data as the forming force input to ANSYS, a commercial structure finite element analysis program. We calculate the forming force data by using the model shape in MAXWELL, a commercial electromagnetic finite element analysis program. We repeat the process until the current is fully discharged by the formed coil. Our results can be used to reduce the error in data transformation with a reduced number of data transformations, because the proposed approach directly links the electromagnetic analysis and the structural analysis after removing the step of the numerical analysis of a graph describing the forming force, unlike the existing electromagnetic forming process. Second, it is possible to simulate a more realistic forming force by keeping a certain distance between nodes using the re-mesh function during the repeated analysis until the current is completely discharged by the formed coil, based on the MAXWELL results. We compare and review the results of the EFPA using the peak value of the forming force that acts on the workpiece (which is the existing analysis method), and the proposed phased EFPA over time approach.

• KEPCO Journal on Electric Power and Energy
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• v.1 no.1
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• pp.21-27
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• 2015

The goal of this study is the size and distribution of the electromagnetic force generated by the current flowing through the second underground line of 154kV power transmission cables by using electromagnetic finite element analysis. So we interpret how mutually electromagnetic force has an effect on the comparable judgement of Trefoil, Duct and Flat, which shows in a numerical arrangement. 154kV OF 1200SQ Cable 1.281km not only is applicable to modeling for underground transmission cable but also examine the effect of line to line, phase to phase and size and direction of the electromagnetic force preparing for the occurrence of normal state and single-phase earth fault, which are arranged in trefoil, duct and flat formation between sections. As showing how the trajectory, and size distribution of the electromagnetic force translate as the arrangement of the cables when a steady-state current and a fault current flows on the underground cables, I hope that when Underground transmission is designed, this data will be useful information.

• Journal of Magnetics
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• v.14 no.4
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• pp.175-180
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• 2009

This paper describes the design and analysis of a tubular linear actuator for intelligent AAP (Active Accelerate Pedal) system. In a driving emergency, the electromagnetic actuator produces an additional pedal force such as the active pedal force and vibration force to release the driver's foot on accelerator pedal. A prior study found that the linear actuator with a ferromagnetic core had a problem in transferring the additional force naturally to a driver due to the cogging force. To reduce the cogging force and obtain higher performance of the AAP system, a coreless tubular linear actuator is suggested. Electromagnetic finite element analysis is executed to analyze and design the coreless tubular actuator, and dynamic analysis is performed to characterize the dynamic performance of the AAP system with the suggested tubular actuator for two types of thrust force.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.979-982
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• 2003

In this study, because of change in electromagnetic force, deformation of the free surface motion of a magnetic fluid is changed. Deformation of the free surface motion of a magnetic fluid for the change in electromagnetic force is discussed and carried out theoretically and experimentally on the basis of Rosensweig Ferrohydrodynamic Bernoulli Equation. Objective of this study explicates free surface motion by electromagnetic force and planes to designed controller. To control free surface of magnetic fluid, it embody designed two-dimensional free surface form of magnetic fluid. By using this characteristics, they applied to oscillator for surface control, flow control, boundary layer control. Strength of magnetic field and height of free surface of magnetic fluid measure as a hall-effect sensor. As performing height control of magnetic fluid, the result will be presented possibility of free surface deformation control.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.12
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• pp.2342-2348
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• 2009

Even though underground transmission cable is an essential transmission method to supply stable power for downtown and population center, the interaction of electromagnetic force by fault current is very large comparing to overhead transmission line due to restricted installation space such as tunnel, and close consideration is required for it. This paper presents countermeasures to reduce and release the effect of electromagnetic force with rope binding and installation of spacer and describes its efficacy through three phase short-circuit test, which will be utilized as basic materials for improvement and development of cleat, hanger, etc. to reduce and release effect of electromagnetic force in the future.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.395_396
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• 2009

This paper handles with effect of electromagnetic force on the cables by fault current accompanied by accident of underground transmission cable. Even though underground transmission cable is an essential transmission method to supply stable power for downtown and population center, interaction of electromagnetic force from fault current is very large comparing to overhead transmission line due to restricted installation space such as tunnel, etc. and close consideration is required for it. This paper describes the effect of electromagnetic force through results of three phase short-circuit test and electromagnetic force analysis using theoretical calculations and electrical evaluation test after three phase short-circuit test, which will be utilized as basic materials for improvement and development of cleat, hanger, etc. to reduce and release effect of electromagnetic force in the future.

• Journal of Korea Foundry Society
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• v.18 no.3
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• pp.240-245
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• 1998

In the view point of the environmental conservation and the energy reduction, the recycling of metal scrap is coming as one of the global subjects in the world. In this study, the movement of intermetallics with electromagnetic force in a melt of a scrap of Al-Si-Cu alloy (JIS ADC12), which was widely used in diecasting process, was investigated in order to eliminate the Fe element, which was usually accumulated in a scrap. In this study, we applied electromagnetic method to eliminate Fe element in ADC12 aluminum alloy scrap which contains 1.64wt.% Fe and the effects of electromagnetic force on the particle movement was visualized and confirmed by water modeling and experiment. As a result, the Fe intermetallic compounds are moved to the direction opposite to that of the electromagnetic force as the force applies, thus eliminated from the bulk metal. Therefore, the content of Fe in matrix decreased from 1.64wt.% to 0.45wt.%.