• Title/Summary/Keyword: 자기흡인력

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Design and analysis of horizontal stocker using transverse flux linear motor (횡자속 선형전동기를 적용한 수령형 스토크 시스템의 설계 및 해석)

  • Chang, Jung-Hwan;Jung, Soo-Jin;Kang, Do-Hyun;Lee, Ji-Young;Hong, Jung-Pho
    • Proceedings of the KIEE Conference
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    • 2003.10b
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    • pp.30-32
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    • 2003
  • 본 논문은 LCD 제조 공정 라인에서 LCD용 원판을 다른 여러 공정으로 이송하는데 사용하기 위한 수평형 스토크 시스템의 설계 및 제작에 관한 연구이다. 구동원으로 제작된 영구 자석 여자 횡자속형 전동기는 높은 공극 자속 밀도를 얻을 수 있는 구조로 일반 선형 유도 전동기나 선형 등기기에 비해 단위 체적당 높은 출력 밀도를 얻을 수 있는 장점을 가지고 있다. 3차원 등가 자기 회로망법을 사용하여 기자력 변화에 따른 추력 및 흡인력과 같은 특성을 해석하였으며 정특성 실험을 통하여 설계 및 해석의 타당성을 검토하였다.

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Acoustic Noise Reduction of A SRM for Fan in Air conditioner (에어컨 팬 모터용 SRM의 소음 저감)

  • Lee, Dong-Il;Shin, Hyoun-Jeong;Lim, Jun-Young;Han, Seung-Do
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11b
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    • pp.816-821
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    • 2002
  • It is getting more important that energy efficiency and manufacturing cost of the electric motor in appliance. The SRM has been alternative choice. But acoustic noise and harshness in this motor was widely known. So this paper had been studied on the noise reduction of a SRM in air conditioner. This works include some parameters regarding to blown noise sources like a reluctance torque ripple, air gap eccentricity, Especially, it was focused on dynamic characteristics of the system based on mechanical viewpoint. It came to successful results. Besides, this gave us a validity of phase excitation in experimental measurements.

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Magnetic Levitation Control through the Introduction of Bogie Pitch Motion into a Control Law (대차 피치운동을 반영한 흡인식 자기부상제어)

  • Ha, Chang-Wan;Kim, Chang-Hyun;Jo, Jeong-Min;Lim, JaeWon;Han, Hyung-Suk
    • Journal of the Korean Society for Railway
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    • v.18 no.2
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    • pp.87-93
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    • 2015
  • The uneven reaction surface profile facing the lift magnets in attractive Maglev vehicles naturally brings about pitch motion of the bogie. In particular, in the placement configuration of the long stator of the linear synchronous motor (LSM) on the track for high-speed propulsion, surface irregularities and the offsets between the stator packs create measurable airgaps, i.e., the clearance between the magnet and the stator, with discontinuously extreme values, resulting in bogie pitch motion. This occurs because the airgap velocities and accelerations derived by the differentiations of the measured air-gaps are used to determine the voltages applied to the magnets. This paper incorporates bogie pitch motion into a control law for each magnet controller to reduce the variations in both the airgap and the pitch angle. The effectiveness of the proposed method is analyzed using a full-scale Maglev vehicle running over a test track.

Torque Ripple Improving and Analysis of Coil-winding Rotor of Magnetic Gear (권선계자형 자기 기어의 고 토크 리플 회전자에 대한 분석 및 개선)

  • Park, Eui-Jong;Kim, Yong-Jae
    • The Journal of the Korea institute of electronic communication sciences
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    • v.15 no.2
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    • pp.259-266
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    • 2020
  • Magnetic gears have the same characteristics as mechanical gears, and each rotor does not come in contact, which is advantageous over mechanical gears in friction noise, heat generation, and maintenance. In addition, when the rotor using the coil-winding is applied, it is possible to control the output of the gear as well as to cut off its own drive in the emergency situation and to change its gear ratio. So the application of the magnetic gear is infinite. However, when the coil-winding rotor is used, cogging torque due to the attraction force between the permanent magnet and the iron core appears, which leads to an increase in the torque ripple component causing the rotor vibration. Therefore, in this paper, various shapes of the coil-winding rotor are analyzed to reduce the torque ripple of the rotor, and the optimum shape for reducing the torque ripple of the magnetic gear is presented.

A Case of Brain Abscess due to Parvimonas micra in a Healthy Child without Dental Disease (특이 과거력이 없는 소아에서 발생한 Parvimonas micra 뇌농양 1예)

  • Lee, Shin Young;Roh, Tae Hoon;Jung, Hyun Joo
    • Pediatric Infection and Vaccine
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    • v.27 no.2
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    • pp.127-133
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    • 2020
  • Parvimonas micra is a non-spore-forming anaerobic gram-positive coccus and a known commensal of the skin, gums, vagina, and gastrointestinal tract. It is rarely associated with severe infections, which typically follow invasive procedures such as dental treatment. We describe a case of a brain abscess caused by P. micra in an immunocompetent 11-year-old boy without periodontal disease. He presented with a 7-day history of headaches and vomiting, and complained of diplopia that began on the day of presentation. He did not have any recent dental treatment or specific past medical history. A brain abscess in the left frontoparietal lobe was noted on brain magnetic resonance imaging. P. micra was cultured from brain abscess aspirate. He was successfully treated with surgical drainage and combined antibiotic therapy with ceftriaxone and metronidazole for 6 weeks.

A Case of Septic Arthritis due to Streptococcus intermedius in a Healthy Child (특이 과거력이 없는 소아에서 발생한 Streptococcus intermedius 화농 관절염 1예)

  • Soo Min Yong;Tae Hun Kim;Hyun Joo Jung
    • Pediatric Infection and Vaccine
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    • v.29 no.3
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    • pp.173-178
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    • 2022
  • Streptococcus intermedius is a small, non-motile, Gram-positive, non-sporeforming, and aerotolerant anaerobic coccus. It is a part of the normal microflora in the oral cavity and upper respiratory, gastrointestinal and female urogenital tracts. It is an opportunistic pathogen that causes serious infections in patients with immunocompromised states or cardiac diseases as a result of trauma or invasive procedures. We describe a case of septic arthritis of the hip caused by S. intermedius in an immunocompetent healthy 7-year-old boy without a history of periodontal disease or invasive procedures. He had hip joint pain three weeks ago, and the fever began on the day of the visit. He had been healthy and had not undergone any invasive procedures recently. Septic arthritis of the hip was indicated in the magnetic resonance imaging of the hip. S. intermedius was identified in the hip joint fluid aspiration and blood culture. He was successfully treated with surgical intervention and antibiotic therapy with ceftriaxone followed by amoxicillin for five weeks.