• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.22 no.4
• /
• pp.121-129
• /
• 2008

This paper deals with the design of BLDC motor replacing ferrite magnet with rare earth magnet. Electric machinery system using ferrite magnet motor is already widespread in large numbers. Electrical appliance makers have a tendency to adhere to existing system using ferrite magnet motors because of redesigning the whole system. This paper designs the rare earth magnet motor untouching the external system dimension and motor outer size. To do the design simply, finite element package is used iteratively To reduce the cogging torque effect and magnetic saturation, stator yoke shape and the groove of the end face of yoke are redesigned.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.28 no.2
• /
• pp.48-53
• /
• 2014

The shield effect of 4 layered shield case was investigated in this paper. The material of the case was non-oriented SiFe sheet with a thickness of 0.5mm. The size of the case was 100mm wide, 100mm high and 300mm long. Relative permeability of SiFe sheet was needed to calculate shield effect. It was obtained from the measurement by a ferrite yoke and from the calculation by eddy current FEM analysis. Three configurations were used to connect both ends of SiFe sheet. First one is a connection by double-welded butt. Second one is to put the sheet the same material above the confronted both ends of the sheet to avoid a leakage magnetic flux. The last one is ideally without any connection. The shield effect of the second one agreed well with the last one and showed the shield effect of -40dB.

• Korean Journal of Computational Design and Engineering
• /
• v.2 no.1
• /
• pp.35-43
• /
• 1997

Concurrent Engineering is one of the methods which are used for the rapid product development. One of the important features in Concurrent Egineering is that the development process is to be parallel and the organization should be cross-functional. In order that the process be parallel and that the organization be cross-functional, an integrated information system such as PDM (Product Data Management) is required. Although the integrated data base is constructed, it could be meaningless if the application softwares were not inter-operable. This study shows an example of intergrated information system from three-dimensional product design to mold design and tooling for the development of Deflection Yoke(DY) which is one of the important parts of Cathode Ray Tube(CRT). A three-dimensional product design software, which is based on a commercial code, has been developed by ourselves. Selective Laser Sintering(SLS), which is one of the rapid prototyping techniques, has been used in this study. Mold design has been done by the three-dimensional way. A newly developed method of mold tooling, which is called Quick Die Manufacturing(QDM), has been introduced.

• The Research Journal of the Costume Culture
• /
• v.19 no.5
• /
• pp.1049-1060
• /
• 2011

The purpose of this study was to develop a shirt pattern that enhances the functionality of golf swing motions. The pattern was made with 3D body surface shape data that changed according to dynamic golf postures. The data were collected from the golf swing motions. The 3D body surface data in golf swing postures piled up on the 3D surface data in a static posture. The results showed that the surface shape data changed more in the address, back swing, and finish postures than the other swing postures. The experimental pattern was developed with 3D surface scan data in those three golf swing motions. The pattern had raglan sleeves and the front-bodied piece was divided into two pieces with a princess line, which comes from armscye line of the address posture. The back bodice piece was divided into three pieces with a yoke line and a back princess line. The yoke line was made by back shoulder shape in the back swing posture. The level of comfort of the experimental garment and commercial golf shirts was evaluated by 38 women golfers. The experimental garment pattern was evaluated to be more comfortable in golf swing postures than commercial golf shirts.

• Progress in Superconductivity and Cryogenics
• /
• v.21 no.4
• /
• pp.59-63
• /
• 2019

To reduce the fault current below the current capacity of a circuit breaker, researches on HTS (High Temperature Superconductor) power cables with fault current limiting (FCL) function are increasing. An FCL HTS power cable transports current with low a impedance during normal operation. Yet, it limits the fault current by an increased inductive or resistive impedance of conducting layer when quench occurs at the FCL HTS power cable by the large fault current. An inductive type FCL HTS power cable uses increased inductive impendence caused by leakage magnetic flux outside the cable core when the quench occurs at a shield layer losing the magnetic shielding effect. Therefore, it has an advantage of less resistive heating than resistive type FCL HTS power cable and temperature increase is suppressed. This paper describes an ideal circuit model for the FCL HTS power cable to investigate the effectiveness of increased inductive impedance when quench occurs at the shield layer. Then, FEM analysis is presented with a simplified model cable composed of various iron yokes to investigate the effect of the shape of yoke on the generation of the inductive impedance.

• Journal of the Korean Magnetics Society
• /
• v.10 no.4
• /
• pp.178-182
• /
• 2000

We have constructed a rotational loss measuring system which consists of two yoke system for rotational magnetization and 4-channel transient recording system for Hx, Hy, Bx and By measurements. Using the constructed measuring system, we have mesaured rotational energy loss for non-oriented electrical steel sheets. Rotational energy loss was depending on the angle between B-search coil and H-search coil, and the direction of rotation (clockwise and counter clockwise). The average of the rotational energy losses under clockwise and counter clockwise was independent of the angle between B-search coil and H-search coil, and we could improve measuring uncertainty using the averaged rotational energy losses.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.49 no.5
• /
• pp.291-296
• /
• 2000

Recently large size color TV and computer monitor are very popular and a lot techniques are being developed to get a high quality picture on the screen through reducing the convergence error among the red, green and blue beams and achieving a high focusing. One of the techniques is considering the mutual effects of the components of the Brown tube. The magnetic deflection yoke, especially, stands immediately next to the electron gun and generates the leakage magnetic fields at the electron gun which affects the trajectories of the electron beams inside the gun. Hence a shield cup made of thin conducting plate is located at the end of electron gun in order to shield the leakage flux from the deflection yoke. Since the red, green and blue beams are placed unsymmetrically the shielding effects of the shield cup on the beams are not same and eddy current controller, made of thin conducting plate, is auxiliary placed inside the shield cup. In this paper a transient magnetic field analysis algorithm is developed using boundary element method, and applied to the analysis of the shielding effects of the eddy current controller of shield cup in an electron gun.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.28 no.5
• /
• pp.115-121
• /
• 2014

The intrinsic simplicity, ruggedness, and simple power electronic drive requirement of a Switched Reluctance Motor(SRM) make it possible to use in many commercial adjustable speed application. The simple magnetic circuit results in a high efficiency drive and low temperature rise, and the drive system provides a good drive characteristics. This paper is provides two phase 4/3 SRM that is similar to two phase 6/3 SRM as aspect to magnetic structure. Although 6/3 SRM does not experience any flux reversal as the flux is in the same direction whether phase A or B is excited, but two phase 4/3 SRM experiences a flux reversal in small part of stator yoke. The flux reversal in two phase 4/3 SRM could be relieved by an adjustment of stator yoke structure. The magnetic analysis and design considerations of the two phase 4/3 SRM have been obtained by the finite element method analysis (FEM).

• Journal of the Korean Society for Precision Engineering
• /
• v.17 no.1
• /
• pp.204-208
• /
• 2000

An approximate similarity theory has been applied to predict the forming load of non-axisymmetric forging of aluminum alloys through model material tests. The approximate similarity theory is applicable when strain rate sensitivity, geometrical size, and die velocity of model materials are different from those of real materials. Actually, the forming load of yoke, which is an automobile part made of aluminum alloys(Al-6061), is predicted by using this approximate similarity theory. Firstly, upset forging tests are have been carried out to determine the flow curves of three model materials and aluminum alloy(Al-6061), and a suitable model material is selected for model material test of Al-6061. And then hot forging tests of aluminum yokes have been performed to verify the forming load predicted from the model material, which has been selected from above upset forging tests. The forming loads of aluminum yoke forging predicted by this approximate similarity theory are in good agreement with the experimental results of Al-6061 and the results of finite element analysis using DEFORM-3D.

• Journal of Aerospace System Engineering
• /
• v.16 no.5
• /
• pp.1-7
• /
• 2022

Recently, satellites equipped with high-performance electronics have required higher power consumption because of the advancement of satellite missions. For this reason, the size of the solar panel is gradually increasing to meet the required power budget. Increasing the size and weight of the solar panel is one of the factors that induce the elastic vibration of the flexible solar panel during the highly agile maneuvering of the satellite or the mode of vibration coupling to the satellite or the mode of vibration coupling to the micro-jitter from the on-board appendages. Previously, an additional damper system was applied to reduce the elastic vibration of the solar panel, but the increase in size and mass of system was inevitable. In this study, to overcome the abovementioned limitations, we proposed a high -damping yoke structure consisting of a superplastic SMA(Shape Memory Alloy) laminating a thin FR4 layer with viscoelastic tape on both sides. Therefore, this advantage contributes to system simplicity by reducing vibrations with small volume and mass without additional system. The effectiveness of the proposed superelastic SMA multilayer solar panel yoke was validated through free vibration testing and temperature testing using a solar panel dummy.