• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제48권11호
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• pp.646-654
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• 1999

This paper deals with PWM patterns for harmonic reduction in inverter fed traction motors and the gear changing techniques for the variable speed drive of traction motor. GTOs are used as switching device of inverter because traction motor is a large load. To derive PWM rattern which can minimize the harmonics with the limited switching frequency, the output current and torque characteristic of SPWM and SHE PWM was analyzed. GTO inverter used for traction motor drive includes harmonics in the output current and torque by the limitation of switching frequency. However, the hybrid PWM method that adopt SPWM in the range of low frequency and SHE PWM in upper frequency range can achieve less harmonic characteristics in GTO inverters. If the traction motor is driven in variable speed by the proposed PWM pattern, 7 times of gear changing is needed. At the instant of the mode change, magnetic flux and torque may be altered and the large current flow. To reduce such an undesirable transient behavior, it is also presented the technique for the gear changing of inverter fed traction motor drive operated with the hybrid PWM. The results are verified by simulations and experiments.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.193-196
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• 2014

Experimantal evaluation of an energy storage device with high rotational speed to store regenerative energy which might be generated during the braking period of the trains is presented. The proposed ESS is small scale model and has 5kW output power, high rotational speed. In general railway trains generate regenerative energy for 10-20 sec when the train brakes and also high traction energy is needed for very short moment (10 sec) when the train increases the traction force. Considering such characteristics of the railway system energy storage device for the railway should have very fast response property. Among the various energy storage devices flywheel energy storage system has the fastest response property, which means that flywheel ESS is the most suitable for the railway system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.265-267
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• 2006

There are various elements that have influence on safety and reliability of high-speed railway vehicles. Among them, mechanical characteristics of traction motors are very important. Therefore, we verified that temperature characteristics have influence on damage and durability of these parts. We designed a measurement system for temperature test, and could measure the temperature of each device by the system. As the result of temperature test, we could confirm that the traction motors on Korean High-Speed Train satisfy the criteria. From this test, we get information of the traction motor about the temperature characteristic during running speed and running time.

• 한국전기전자재료학회논문지
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• 제19권12호
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• pp.1123-1127
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• 2006

There are various elements that have influence on safety and reliability of high speed railway. Among them, mechanical characteristics of traction motors are very important. Therefore, we verified that temperature characteristics have influence on damage and durability of these parts. We designed a measurement system for temperature test, and could measure the temperature of each device by the system. As the result of temperature test, we could confirm that the traction motors on Korean High-Speed Train satisfy the criteria. From this test, we get information of the traction motor about the temperature characteristic during running speed and running time.

• 대한족부족관절학회지
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• 제1권2호
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• pp.81-88
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• 1997

The arthroscopic ankle arthrodesis is one of the good method of the ankle arthrodesis. Mechanical distraction of tibiotalar joint is an absolute necessity for adequate visualization and operative instrumentation. However, there are several disadvantages. Thus we performed arthroscopic ankle arthrodesis using calcaneal traction in three cases and achieved following results. 1. The procedure is easy and the operation time is shorter than the other arthroscopic ankle arthrodesis. 2. The risk of neurovascular damage and infection is reduced by using calcaneal traction. 3. It does not require the expensive distraction device. 4. The adequate visualization for operative instrumentation is obtained.

• 열처리공학회지
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• 제35권1호
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• pp.20-26
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• 2022

This paper was designed to prevent intervertebral disc escape and treatment. we produced downsized lumbar traction bed at home and automated system depending on weight and muscle mass by using 3D print and Arduino to confirm the possibility of prototyping. Hence, we checked muscle mass 10 males in their 20s with different exercise conditions, and it shows that average muscle mass of group who exercised was 56.63kg, and non-exercise group was 50.8 kg. this is shows lumbar repetitive exercise can show the traction therapy effect can be seen traction therapy effect. In addition, we installed wooden doll substitute people with spring and test changing of length. Traction bed has the steps ranging from 1 to 4, in which the motor with torque and rpm, ranging from 4.7 to 5.5 kgf and from 4.5 to 5.3 rpm, respectively. The motor controlled with the voltage of Arduino was operated for the length of the spine to be stretched to 4-5 mm. As increasing the weight of the wooden doll by 10g, it was confirmed that the spring increased by 4-5 mm from the first step to the fourth step.

• Clinical Endoscopy
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• 제55권3호
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• pp.443-446
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• 2022

Percutaneous endoscopic gastrostomy (PEG) is a common method for providing long-term enteral nutrition to patients. PEG tube placement and removal are relatively safe; generally, a PEG tube can be removed using gentle traction, and excessive bleeding is rare. The over-the-scope clip system is a new device that can be used for gastrointestinal hemostasis and for closing gastrointestinal fistulae. In the present case, a 68-year-old male patient had to remove the PEG tube because of persistent leakage around the PEG tube. Although it was gently removed using traction, incessant bleeding continued, with a Rockall score of 5 points, even after hemocoagulation was attempted. An over-the-scope clip device was used to achieve hemostasis and fistula closure.

• Journal of Oral Medicine and Pain
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• 제23권4호
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• pp.369-377
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• 1998

A patient with TMJ osteoarthritis and anterior open bite was treated with an intermaxillary traction device. Pretreatment examination revelaed a pain in both TMJ during mouth opening, moderate tendernesso f left sternocleidomastoid and right trapezius muscles. Anterior open Bite was aobserved with interincisal distance of 2mm. Tomograms and MRI showed anterior disc displacement withouit reductoin of both temporomandibular joints, and the condyles were flattened and slightly eroded. A pair of full-coverage occlusal appliances was made on both maxillary and mandibular dentition, with pivoting fulcrum on the site of the second moalr. Traction force was gained by the intermaxillary orthodontic elastics which were hooked by orthodontic brackets on the labial surfaces of the upper and lower anterior and premolar teeth. After 8 weeks of traction treatment, the joint pain was subsided completely and the anterior open bite was closed to get an edge to edge relationship of anterior teeth.

• 한국자동차공학회논문집
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• 제21권6호
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• pp.209-217
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• 2013

This paper presents a control strategy of 4 wheel drive (4WD) vehicles. Proposed control strategy has simple structure and can easily apply to various vehicles with low cost and time. It is consist of feedforward control for traction ability, fedback control for minimizing the wheel speed difference and yaw control for lateral stability. In addition, to integrate the traction and stability control, a blending function is applied. To evaluate the feasibility of the proposed control strategy, actual vehicle experiment is conducted after deciding the tuning parameter through the simulation. The simulation is accomplished by CarSim and Matlab/Simulink and the actual vehicle test is conducted using full size Sports Utility Vehicle (SUV) equipped rear wheel based solenoid type 4WD device.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1438-1444
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• 2007

Standard Gate Turn Off (GTO) Thyristor drive technology results in inhomogeneous turn-on and turn-off transients which in turn needs costly dv/dt and di/dt snubber circuits. Added to this GTO is bulky in size, needs external cooling, slower switching time etc. The development of high voltage Insulated Gate Bipolar Transistor (IGBT) have given new device advantage in the areas where they compete with conventional GTO technology. Indian Railway has developed first IGBT based traction converter and was commissioned in November 2006. Some of the supremacy of IGBT are smaller in size, no external cooling is required, built in power supply which enhances reliability, lower switching losses which leads to higher efficiency, reduced gate drive, high frequency operation in real time etc. These advantages are highlighted along with IGBT Traction system in operation.