• Journal of Biomedical Engineering Research
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• v.7 no.1
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• pp.21-34
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• 1986

In this paper, we described the ECG telemetry system via the Public Telephone Line. The system consist of a signal acquisition and measurement section, a signal processing section, and a signal transmission section. It used 8 bits microprocessor. The transmission section is composed of 3 ch. analog modulators and 1 ct. digital modem. Especially, using the digital modem, signal is transmitted with about 50n data reduction ratio by the TP (Turning Point) algorithm. The acoustic coupler or inductive coil for linking the public telephone line are used. The speed of the digital modem is 300 baud rate. The MCBS (Multi Channel Biotelemetry System) is tested and evaluated through the experiment.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.02a
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• pp.276-279
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• 2003

The superconducting synchronous machine(S.S.M) including generator and motor has different electromagnetic structure from the conventional machine. With the help of superconductor having much higher operating current density than normal conductor, S.S.M can eliminate most of iron core filling inside of the conventional machine. This air-cored structure could be analysed and designed theoretically based on 2-dimensional(2-D) magnetic field distribution assuming that the windings are extended infinitely toward the axial direction. However the actual structure of S.S.M has the end regions interconnecting the straight parts of the same cross-section with the 2-D model. Therefore, this actual 3-D model has smaller field distribution than the 2-D model. In this paper, we consider the effect of the end regions on the output of a HTS model motor and suggest more accurate design approach through comparison of 2-D and 3-D magnetic field analysis.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.61-66
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• 1987

The metals has been used to the electric motor frame and brackets. The purpose of this project is to substitute engineering plastic doter frame for metal because of the demand for small size and environmental reliability. As a result of considering of mechanical strength, heat and injection characteristic of engineering plastics. PBT GF 30 has been selected as the material of electric motor frame including brackets. Design of the frame has been carried out on enough consideration of mechanical strength, heat-resisting and endurance. For the prevention of lower efficiency, the length of airgap between stator and rotor is reduced and for the reduction of vibration, slot combination is changed and the length of stator is increased.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.11
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• pp.1219-1226
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• 1990

This paper is to report the results on the design and construction of a thermal plasma generator with high current DC source. Also, this paper presents the methods to stabilize plasma and to find effects of process variables on plasma characteristics. For this purpose, the reaction chamber, vacuum system, plasma generating torch, magnetic field generating coil with power supply, high current DC source and the other parts have been designed. Fundamental properties of the thermal plasma under various conditions have been measured and analyzed. Magnetic Reynolds Number has been introduced to explain the relationship between plasma and external magnetic field. Through this number, the effect of magnetic field on the plasma has been explained under various flow rates and pressure. A sudden increase in the plasma voltage has been observed with the increase of magnetic field. From this, fundamental changes in plasma flow are believed to occur at the nozzle, and an effort to explain the phenomenon has been tried.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.5
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• pp.470-478
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• 1991

In this study, a variety of characteristics were shown experimentally under mechanically unbalnced states expected in a practicl system that linear motor is used as a driving motor of magneticlly levitated transit and the design criterion of the linear motor has been proposed. Since, with slip being at 0.1, end effect was reduced a little to increase thrust about 6.14 percents in case thatsinusoidal current conducted 5[A] in short coil at each end of linear motor for compensation of it, if the ratio of sinusoidl current versus input currents is adjusted properly, it is thought that this method small be effective one. And if the gap of exit region is bigger than that of entry region, end effect will be reduced. As a result, more effective driving will be obtained.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.247-249
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• 2001

In our research, we designed a small step motor with 2-phase structure and a micro step driving IC, which is used in an automotive instrument. The step motor for the automotive instrument has the better advantages than a cross coil type motor. These advantages are the characteristics with a good linearity, a fine accuracy, a low noise and so on.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.96-98
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• 2001

In this paper, the equivalent magnetic circuit and FEM are used to calculate force density of linear BLDC motor. The equivalent magnetic circuit is hard to exact compose for analysis model and it is just applied to linear system. To flexible design and reducing the calculated and analyzed time, magnetic circuit has to be used for designing the linear BLDC motor and deducing equation of force density. Force density as parameter of permanent magnet and coil-side width that are important to determined force density can be estimated using equation of force density. FEM is used to prove reliability of equation of force density and to consider the nonlinear system. Equivalent magnetic circuit and result of FEM are similar, but it is little different by friction loss at the experiment.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2151-2155
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• 1998

The traveling wave type ultrasonic motor(USM) has no electro-magnetic circuits( coil or core). The driving principle of the USM is based on high-frequency mechanical vibrations and frictional force. The USM, thus, is fed by two-phase high - frequency sinusoidal inverter using its series resonant parasitic components. For the using of series resonant type inverter, it should be needed to a USM parasitic capacitance and a proper inductor chosen. In this paper, the values of optimal inductance are designed and the efficiency of USM drives is achieved. The effectiveness of the proposed design is demonstrated by experiments.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.04a
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• pp.7-10
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• 2002

We designed the flyback planar transformer, which had 8W capacity, with 70V input voltage and 8.2V output voltage for the establishment of design method and the confirmation of application possibility. The numerical value of inductance measured under the switching frequency of 120 kHz was 1650 ${\mu}H$, which was the inductance efficiency of 85~87% against theoretical value. The A.C. resistance of primary and secondary coil was 4.2 ${\Omega}$ and 0.25 ${\Omega}$ respectively. On the other hand, the quality factor for each wound numbers showed quite a high value of 158 and 75 respectively. And the Coupling Factor was 0.96~0.97 under 120 kHz switching frequency. And the shape of the output wave of the planar transformer at 70V input voltage was a stable square wave.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.817-818
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• 2006

A 2.0T class HTS conduction cooled magnet was designed. Designing of magnet shape was performed through two steps. First step is to find a basic cross section for minimize the amount of conductor used and second step to optimize the coil shape to satisfy the magnetic field homogeneity. The magnetic fields was analyzed with FEM and the critical current value of magnet was also expected with the result of field analysis and the Ic to B curve of Bi-2223 HTS tape.