• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 추계학술대회 논문집 전력기술부문
• /
• pp.59-61
• /
• 2003

This paper demonstrates an analysis of harmonics at the high speed railway substation and proved on this countermeasure using the PSCAD/EMTDC simulation tool. First, high speed railway feeding system is composed using PSCAD/EMTDC electrical railway feeding system model in advance. Second, This paper applications line capacitance values as feeder-trolley, trolley-rail and feeder-rail to analysis harmonics more accuracy in advance did not application. This capacitance values calculate using the EMTP(Electro Magnetic Transient Program). Third, the tractions are arranged in the section that substation supplies power, and this paper take the simulation each case(fractions composition amount) to see harmonic propagation from traction to substation. As a result, generated harmonics at traction can confirmed that harmonics did not reduce at utility source. This harmonics have an influence on bulk power system. Finally, this paper introduces the methods of harmonics effect minimum. This paper proved harmonics reduce effect through the passive filters application.

• 전기학회논문지
• /
• 제66권12호
• /
• pp.1866-1872
• /
• 2017

This paper presents the design of in-wheel type Switched Reluctance Motor (SRM) which can be used as both traction motor and power pickup device in a wireless charging system of electric vehicles. The SRM acts as a traction drive in driving mode and a power receiver in charging mode to avoid any additional weights. Double stator axial field SRM is used due to its structure that can be mounted inside the wheel. The charging circuit is integrated with the asymmetric converter and phase windings of SRM, reducing the cost and size of the system. Magnetic resonance is implemented to increase the efficiency. Simulations done in Maxwell and Simplorer verify the effectiveness of the proposed system.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 1999년도 추계학술대회 논문집
• /
• pp.360-367
• /
• 1999

An inverter-driven induction motor is used as the traction motor for a high speed drive system that required safety, reliabillity, performance, compact size owing to the space and weight alloted for attaching to train, etc. particularly it is possible to happen the saturation effects of flux density at constant voltage-frequency region and then increase very higher than the at lowed capacity of no-load current and temperature in any case. therefore the optimum design of core, optimum voltage-frequency ratio, adoption of high grade magnetic core have been developed and researched for preventing these problems. this paper show the saturation effects of traction rotor by measuring the induced voltage of search coil at stator teeth and presents optimum voltage-frequency ratio as well as optimum core design through the comparison with efficiency, power factor, load current and no-load current for korea high speed train.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
• /
• pp.537-540
• /
• 2003

This study was investigated to fabricate the porcelain materials with high magnetic characteristics. The high characteristics of the magnetic porcelain materials were achieved at the following conditions; powder sizes of isotropic Sr-ferrites with $1{\sim}2\;mm$ and magnetic powder infraction of 30 wt%. The magnetic tea cups with 3-mm-thick at the optimum conditions indicated the high magnetic characteristics such as the surface flux density of 178 G, the remanent flux density of 240 G, and the intrinsic coercivity of 3910 Oe.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
• /
• pp.1637-1639
• /
• 2005

The measurement of magnetic field is performed about DC and AC magnetic field in test track of depot. The test point is cap, on the converter/inverter box, on the traction motor, on the APSE and on the line filter, the height of measurement is bottom and 50 cm height. In case of AC magnetic field, the selected specific frequency is measured on the converter/inverter box. The AC magnetic field is checked and analysis through RS-232C and notebook PC. The DC magnetic field is measured by using the Hall Probe, test result is saved and analysis by PXI system. On the line filter, the maximum value is 1.4 mT in case of DC magnetic field and 0.044 mT in case of AC magnetic field at 50 Hz.

• Clinics in Shoulder and Elbow
• /
• 제22권3호
• /
• pp.139-145
• /
• 2019

Background: The present study was undertaken to evaluate the relationship between location of the rotator cuff tear and shape of the subacromial spur. Methods: Totally, 80 consecutive patients who underwent arthroscopic repair for partial thickness rotator cuff tear were enrolled for the study. Bigliani's type of the acromion, type of subacromial spur, and location of partial thickness tear of the rotator cuff were evaluated using plain X-ray and magnetic resonance imaging. We then compared the groups of no spur with spur, and heel with traction spur. Results: Of the 80 cases, 25 cases comprised the no spur group, and 55 cases comprised the spur group. There was a significant difference in type of tear (p=0.0004) between these two groups. Bursal side tears were significantly greater (odds ratio=6.000, p=0.0007) in the spur group. Subjects belonging to the spur group were further divided into heel (38 cases) and traction spur (17 cases). Comparing these two groups revealed significant differences only in the type of tear (p=0.0001). Furthermore, the heel spur had significantly greater bursal side tear (odds ratio=29.521, p=0.0005) as compared to traction spur. Conclusions: The heel spur is more associated to bursal side tear than the traction spur, whereas the traction spur associates greater to the articular side tear.

• Journal of Oral Medicine and Pain
• /
• 제37권4호
• /
• pp.205-211
• /
• 2012

35세 여자환자가 갑작스런 개구장애와 함께 발생한 급성 교합변화를 주소로 내원하였다. 환자는 이전 수년 동안의 관절잡음의 병력을 가지고 있었으며 관절잡음의 소실과 동시에 개구제한이 발생하였음을 보고하였다. 환자는 개구제한과 함께 개구시 우측 악관절의 통증을 호소하였으며 구강내 교합 검사 시 전치부의 개교합과 함께 하악이 우측으로 전위된 양상이 관찰되었다. 또한 좌측으로의 측방운동량 또한 감소된 것으로 관찰되었다. 자기공명영상에서 우측 악관절에서 비정복성 관절 원판 전방 변위가 관찰되었으며 후방 관절강의 협착이 관찰되었다. 이 환자는 우측 악관절의 비정복성 관절원판 전방변위로 진단되었으며, 급성 교합변화는 변위된 관절원판에 의해 야기된 과두위치의 변화로 초래된 것으로 추정하였다. 처음 3개월간의 물리치료와 약물치료와 병행된 안정교합장치요법에서는 만족할 만한 치료결과를 얻지 못하였으나, 그 다음 약 8개월간 사용된 악간견인장치 치료를 통해서 통증 및 교합변화가 해소되었으며 정상적인 개구량으로 회복되었다. 술후 촬영된 자기공명영상에서 우측 과두가 재형성된 양상을 관찰할 수 있었다.

• Journal of Korean Neurosurgical Society
• /
• 제41권5호
• /
• pp.295-300
• /
• 2007

Objective : Unilateral facet dislocation of the cervical spine occurs by flexion and rotation injuries and cannot be easily reduced by axial traction. We analyzed 14 consecutive patients with unilateral facet dislocation of the cervical spine to increase knowledge about anatomical reduction of locked facet and factors for successful reduction. Methods : Fourteen patients [10 men and 4 women] with unilateral facet dislocation of the cervical spine were retrospectively analyzed. Plain X-ray, computerized tomography scan, and magnetic resonance imaging were performed. All patients underwent manual reduction and surgery with anterior interbody fusion and plate fixation. The manual reduction was performed by neck flexion and rotation to the opposite side of dislocation, followed by rotation and flexion of the head toward the side of dislocation and extension with relaxation of traction. Mean follow-up period was 17 months. The level of spine, amount of subluxation, combined facet fracture, and time from injury to initial reduction were analyzed using the data obtained from medical records. Results : Thirteen [93%] patients were reduced successfully. Immediate reduction was achieved in 7 patients but failed in 7 patients. Seven patients underwent delayed closed reduction under general anesthesia, and successful reduction was achieved in 6 patients. Only one patient with bone chips between articular facets failed to achieve anatomical reduction. Conclusion : In order to reduce the locked facet more easily and safely, we recommend manipulative traction with anterior interbody fusion and plate fixation under general anesthesia after being aware of spinal cord injury with magnetic resonance imaging.

• 제어로봇시스템학회논문지
• /
• 제17권6호
• /
• pp.566-572
• /
• 2011

In recent semiconductor and FPD (Flat Panel Display) manufacturing processes, high clean-class delivery operation is required more and more for short working time and better product quality. Traditionally SLIM (Single-sided Linear Induction Motor) is widely used in the liner drive applications because of its simplicity in the rail structure. A magnetically levitated (Maglev) unmanned vehicle with SLIM traction, which is powered by a CPS (Contactless Power Supply) can be a high precision delivery solution for this industry. In this paper unmanned FPD-carrying vehicle, which can levitate without contacting the rail structure, is suggested for high clean-class FPD delivery applications. It can be more acceptable for the complex facilities composed with many processes which require longer rails, because of simple rail structure. The test setup consists of a test vehicle and a rounded rail, in which the vehicle can load and unload products at arbitrary position commanded through wireless communications of host computer. The experimental results show that the suggested vehicle and rail have reasonable traction servo and robust electromagnetic suspensions without any contact. The resolution of point servo errors in the SLIM traction system is accomplished under 1mm. The maximum gap error is ${\pm}0.25mm$ with nominal air gap length of 4.0mm in the electromagnetic suspensions. This type of automated delivery vehicle is expected to have significant role in the clean delivery like FPD glass delivery.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2011년도 전력전자학술대회
• /
• pp.312-313
• /
• 2011

Recently, many industrial electric vehicles have been developed using various ac-motor drive technologies including field oriented vector control. Generally, a magnetic encoder is installed to have resistance to vibration and dust, and it is cost-effective. However, it is difficult to get an accurate rotor speed for high performance of vector control, because a resolution of the magnetic encoder is low and its phase accuracy is poor. In order to overcome this hardware problem, this study proposes a speed measurement algorithm using moving window for low-resolution magnetic encoder. This algorithm is experimentally tested and successfully applied to traction application of industrial electric vehicle.