• Proceedings of the KIEE Conference
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• 2007.10c
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• pp.65-67
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• 2007

In this paper describes the design and characteristic analysis of a novel 2-DOF(Degree of Freedom) motor. For multi DOF actuating, several numbers of motors have been used. But the using of normal motors they connected each other in single joint, have necessary to a several type of complex power transmission devices. The 2-DOF motor can drive pan, tilt motion in only one unit and it is not necessary to use additional gears and links parts. Therefore by the using of 2-DOF spherical motor ran eliminate; combined effects of inertia, backlash, non-linear friction, and elastic deformation of gears. The validity of the analysis is confirmed by 3D finite element method.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.4 s.235
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• pp.518-525
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• 2005

The electromagnetic noise generates when natural frequencies of a stator core with wingdings and frame coincide with or approach natural frequencies of the magnetic motive force. In order to suppress such noise, the estimation of natural frequencies of the motor is important at the design stage. However, the natural frequency analysis is not so easy because motor stator is in the laminated plate structure and windings are composed of wires, insulation sheets and vanishs. Thus the accurate prediction of the equivalent material properties of windings becomes an essential task. In this paper, we derive the equivalent material properties using homogenization methods.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.95-100
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• 2007

The traction motor for High Speed Train is being required reliability and stability for high-speed operation. And also required low noise level, high performance, compact size owing to the space and weight limitation for attaching to train, etc. As a result of requiring the low noise level and high power capacity, it is adopted forced-air-ventilation insead of self-ventilation that is generally used on electric multiple unit. Traction motor is cooled by cooling air through the air-ventilation hole. When the traction motor is operated with forced-air-ventilation, there is some abnormal noise in the specific RPM. This paper is dealing with the method to reduce the resonance phenomena by adopting the rotor blade.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.810-811
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• 2015

In this paper, we investigate the optimization design for a spoke type motor with the characteristics of high torque density and high-efficiency. This motor has a high output per unit volume. In order to reduce noise and vibration caused by a high cogging torque, optimization design of the rotor and stator have been conducted using both Response surface method (RSM) and Finite elements method (FEM). In this paper, we show the potential for this motor to efficiently replace existing interior permanent magnet synchronous motors (IPMSM) in a wide range of industries.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.955-957
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• 1998

Switched reluctance motor(SRM) has the advantages of simple structure, low rotor inertia, and high poer rate per unit volume. However, position sensor isessential in SRM in order to synchronize the phase excitation to the rotor position. The position sensors increase the cost of drive system, and tend to reduce system reliability. This paper investigtes the speed control of sensorless SRM. The proposed system consists of position detection circuit, dwell angle controller, digital logic commutator, PI speed controller and 4-phase inverter. The performances in the proposed system are verified through the experiment.

• Tribology and Lubricants
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• v.15 no.1
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• pp.108-115
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• 1999

The electrical and frictional properties of oil-impregnated sintered-metal bearing (OSB) and herringbone-grooved fluid bearing (HFB) with varying loads and speeds were measured. OSB shows very good performance up to 20,000 rpm and 0.05 N, and HFB successfully works up to 35,000 rpm and 0.05 N. From the endurance tests on start-stop and continuous operation, it was confirmed that those bearings could be mass-produced fur use on scanner motor in a laser scanner unit.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.252-257
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• 1990

For the position control of BL-DC motors, 2.phi.-3.phi. conversion unit, hysteresis band device, and PWM pulse generation are required. By utilizing a single-chip processor INTEL 8097BH, we cover all required functions. As a result, no analogue device is employed in this control scheme, so that it makes BL-DC motor controller simple and flexible. Furthermore, the single-chip processor is utilized for the nonlinear coordinate transformation which is necessary for the linearization of the motor system.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.891-893
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• 2003

This paper Presents the optimum design of Brushless DC Motor using multi-objective function Neural Network to maximize efficiency and Ratio of Torque Per unit weight.

• Journal of the Korean Society for Railway
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• v.8 no.6 s.31
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• pp.520-524
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• 2005

It is consequential to reduce the environmental impact of a product for sustainable development in 21st Century. In the field of transportation, especially, the technological market concerned about reduction and assessment of greenhouse gas emission is expected to be extended. The LCA gas been esteemed and utilized as a realistic alternative greenhouse gas emission is expected to be extended. The LCA has been esteemed and utilized as a realistic alternative to improve the environment by the assessment of environmental impacts. In this study, simplified life cycle assessment(S-LCA), was performed to analyze the environmental impacts quantitatively, which were produced through the life cycle of a electric motor unit(EMU). The object of the present work is rth investigate main parameters of environmental impacts and to establish the plans to improve the environment impact of EMU. As a result of quantitative assessment for environmental impact and manufacturing, the EMU carbody made of SUS showed acidification(AD) and marine water aquatic ecotoxicity(MAET) the most, while that made of Mild showed high impact of global warning(GW) and abiotic resources depletion(ARD). For the SUS EMU, the high AD and MAET impact is occurred by the discharged pollutants during acid-washing process. Also, high value of GW and ARD for Mild EMU is resulted from the consumption of iron ore, coal and crude oil during manufacturing. Therefore, the environment impact of carbody would be decreased by enhancing of energy efficiency and the lightening the weight of it.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.30 no.1
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• pp.28-33
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• 2019

Background and Objectives : Laryngeal electromyography (LEMG) is valuable to evaluate the innervation status of the laryngeal muscles and the prognosis of vocal fold paralysis (VFP). However, there is a lack of agreement on quantitative interpretation of LEMG. The aim of this study is to measure the motor unit action potentials (MUAP) quantitatively in order to find cut-off values of amplitude, duration, phase for unilateral vocal fold paralysis patients. Materials and Method : Retrospective chart review was performed for the unilateral VFP patients who underwent LEMG from March 2016 to May 2018. Patient's demography, cause of VFP, vocal cord mobility, and LEMG finding were analyzed. The difference between normal and paralyzed vocal folds and cut-off values of duration, amplitude, and phase in MUAP were evaluated. Results : Thirty-six patients were enrolled in this study. Paralyzed vocal fold had significantly longer duration (p=0.021), lower amplitude (p=0.000), and smaller phase (p=0.012) than the normal. The cut-off values of duration, amplitude, and phase in MUAP for unilateral VFP were 5.15 ms, $68.35{\mu}V$, and 1.85 respectively. Conclusion : An analysis of MUAP successfully provided quantitative differences between normal and paralyzed vocal folds. But, additional research is needed to get more available cut-off value which is helpful to evaluate the status of laryngeal innervations.