• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.733-734
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• 2006

In this parer, characteristics of the flexible rail in levitation control system are analysed. The magnetic levitation system is an electromagnet type and is full-scaled vehicles. The system consists of electromagnet, chopper, flexible rail, secondary suspension system and levitation controller. The mathematical modelling for the whole system is carried out. Especially, the flexible rail is modelled using second-order mass-spring-damper system. Using the derived model, the dynamic characteristics for the system are presented with different vehicle speed.

• Proceedings of the IEEK Conference
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• 2002.06e
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• pp.117-120
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• 2002

This paper is to develop the sensing system for opening-force measurement such as O-Ring muscular meridian. We designed to overcome the functional limit that the conventional force-sensor can measure just the closing-force. Therefore, the new sensor can meet a variety of application as well as O-Ring test. The structure of the new sensor is an actuator-type system using an electromagnet. That is made up of mechanical system, electromagnet, current transformer and computer interface circuit. Driving software and user interface program of the new sensor system also is explained in this paper.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.3
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• pp.299-306
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• 2008

The electromagnet in Maglev vehicles controls the voltage in its winding to maintain the air gap, a clearance between the electromagnet and guideway, within an allowable deviation, with strongly interacting with the flexible guideway. Thus, the vibration characteristics of guideway plays important role in dynamics of Maglev vehicles using electromagnet as an active suspension system. The effects of the guideway's vibrational characteristics on dynamics of the Maglev vehicle UTM-01 are analyzed. The coupled equations of motion of the vehicle/guideway with 3 DOFs are derived. Eigenvalues are calculated and frequency response analysis is also performed for a clear understanding of the dynamic characteristics due to guideway vibration characteristics. To verify the results, tests of the urban Mgalev vehicle UTM-02 are carried out. It is recommended that the natural frequency of the guideway be minimized and its damping ratio in the Maglev vehicle with a 5-states feedback control law as a levitation control law.

• Journal of the Korean Magnetics Society
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• v.4 no.2
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• pp.179-183
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• 1994

A high efficiency small electromagnet (22 mm air gap and $40{\times}25mm^{2}$ core's cross section) suitable for measuring magnetostriction and magnetic anisotropy was biult. The magnet could be minaturized by reducing the measuring space and time. The excitation current of the electromagnet was supplied for only a few second of measuring time. Cooling system of the electromagnet could be eliminated since the dissipation energy was very small. An 0.5 T magnetic field was generated with 180 W power consumption. The values of magnetostriction and magnetic anisotropy were measured with a very sensitive capacitance cell with resolution of $10^{-8}$ and 1 nJ. The torque was calibrated using a soft magnetic ribbon's shape anisotropy.

• Journal of the Korean Magnetics Society
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• v.12 no.4
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• pp.137-142
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• 2002

A precision magnetic field was generated by the NMR magnetometer and electromagnet system. The current and field feedback systems are used to control of magnetic field in the electromagnet using computer. Stability of magnetic field according to results that compare field and current feedback, current method is better than 2 times. The stability of magnetic field with current feedback improved 10 times compared with no feedback. This system is used for the calibration of magnetometers and the testing related to magnetic fields.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.1
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• pp.163-171
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• 2000

The aim this study is to provide fundamental informations for the development of magneticfluid damper. To achieve the aim. the damping effect of magneticfluid is investigated by experiments that the diameter of inner circular bar and the input amplitude vary in the magnetic field generated by the permanent magnet and the electromagnet. From the study, the following conclusive remarks can be made. As the diameter of inner circular bar and the input amplitude increase. the damping effect is improved. And we can know that as the contact area between inner circular bar and magneticfluid increases, damping ratio is improved. Also we consider the cases that there is magnetism generated by electromagnet and DC voltage is supplied to electromagnet from 10V to 50V by 10V. In these cases, the amplitude ratio decreases sharply from 1.8 1.0 And for these cases, the damping ratio is .745.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.740-743
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• 2005

Most works of the large vertical ceiling structures have been performed by human manually. These works require much more operation costs, labors and times, etc. Beside most people avoid this works because of it's characteristic such as danger, dirty and difficulty. So necessity of automation for these works has been rising. This automation needs a wall climbing mobile vehicle because of the movement of platform large workspace. In this study, we aim at develop the wheel which can be used for vertical wall-climbing mobile robot using electromagnet wheel. The wheel proposed can be available for several working processes on structures which consist magnetic substance.

• Proceedings of the Korean Magnestics Society Conference
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• 1993.03a
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• pp.30-31
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• 1993

• 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.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2002.02a
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• pp.318-321
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• 2002

Superconductivity has various applications in the whole industry such as the generation of high magnetic field for medical care and diagnosis, the lossless power transmission, environment-friendly vehicles and clean energy storage systems. This paper deals with the High-Tc superconducting(HTS) power supply using heater-triggered switch for the charging of the superconducting magnets. HTS superconducting power supply consists of two heaters, an electromagnet, and Bi-2223 solenoid and Bi-2223 pancake is used as a superconducting load, similar to real HTS magnet. The timing sequential control of two heaters and an electromagnet is an important factor to generate pumping- current in the Bi-2223 load. The thermal analysis of switching parts of the Bi-2223 solenoid according to the heater input was carried out. Based upon the analysis, the 0.8A of heater current were optimally derived. The maximum pumping current reached 1.7A.