• Journal of Advanced Marine Engineering and Technology
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• v.34 no.6
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• pp.806-815
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• 2010

Gear trains are combined with the planetary gear units and helical gear units. It is known that the combination type is decisive to the system performances of the transmissions. In this paper, within the commonly used range of the design requirements for medium and large scaled (1~8 MW) wind turbines, the transmission characteristics of the typical layouts of the gear train are investigated. According to the international standard by ANSI/AGMA/AWEA 6006-A03, the gear boxes are basically designed and compared with respect to the system lifes of 99% reliability, total weight, the power densities, overall diameter/length and the maximum stresses of the gear teeth. With these comparison works, the characteristics of the layouts of gear trains are discussed.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.6
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• pp.1235-1242
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• 2018

When the wind speed changes rapidly, the wind turbine is stopped for the safety of the power system and the mechanical system. At that moment, the wind turbine gearbox is damaged and broken due to the contact load of the gearbox. In addition, the problems such as increasing frictional heat and deteriorate of the brake occur, because the power of the blades is transmitted directly to the brakes. This paper proposes a hybrid magnetic gear shape that solves the problem caused by the contact of the mechanical gear, which is the power transmission device of the wind power generation system, and the power cutoff system. The shape of the hybrid magnetic gearsuitable for the wind power generation system is derived through the torque and loss analysis according to the shape of the hybrid magnetic gear by using the two dimensional finite analysis method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.893-899
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• 2014

X-band antenna has been widely used to effectively transmit the high resolution image data from the observation satellite to the ground station. To achieve above mission, X-band antenna is mainly composed of the 2-axis gimbal system using stepping motors and gears. However, the micro-vibration induced by the stepping motor actuation and the imperfect gear teeth alignment during this on-orbit operation is the main source of image quality degradation. In this paper, X-band antenna combined with a blade gear for micro-vibration isolation was suggested and investigated. The structural safety of the blade gear with low rotational stiffness was confirmed by structure analysis based on the derived torque budget. The isolation performance of the X-band antenna with the blade gear was verified through micro-vibration measurement test using the dedicated micro-vibration measurement device proposed in this study.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.2
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• pp.267-275
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• 2012

In this study, normal wind load and blast wind load are modeled mathematical. And the periodical torque and bending moments transmitted to the main shaft of wind turbine are investigated. A normal wind model assumed, of which the wind velocity is increased according to the height from ground. The average values and the harmonic terms of the transmitted moments are studied on the wind direction of range $-45^{\circ}{\sim}45^{\circ}$ and the bending moment characteristics are examined, which is regarded as the main source of the misalignment of gear train. In normal wind load case, excitation frequency is 3X (X : Rotor speed). When the wind direction is $+22.5^{\circ}$, the horizontal axis of bending moment occur the 50% of main torque. This result leads to edge contact of gear teeth by shaft elastic deformation. In blast wind load case, excitation frequency are 3X,6X,9X. Additional, in the (+) direction of wind load, relative harmonic percentage is increase.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.3
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• pp.253-261
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• 2014

In this paper, vibration analysis of power differential gear train for 2.5MW wind turbine system is analyzed. which system is composed of two planetary gear set, one helical gear set and main shaft that connected by flange. Planetary gear set, helical gear set, main shaft are modeled in MASTA program and housing, torque arm, carrier, flange components are modeling by finite element method. Each models are combined by component mode superposition. To analysis of natural vibration characteristic about 2.5MW wind turbine gear train was performed and check about critical speed with wind load, mass unbalance, angle misalignment excitation frequency.

• Journal of Aerospace System Engineering
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• v.12 no.2
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• pp.46-58
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• 2018

A two-axis gimbal-type X-band antenna is widely used to transmit bulk image data from high-resolution observation satellites. However, undesirable microvibrations induced by driving the antenna should be attenuated, because they are a main cause of image-quality degradation of the observation satellite. In this study, a pseudoelastic memory alloy (SMA) gear was proposed to attenuate the microvibrations by driving the antenna in an azimuth angle. In addition, the proposed gear can overcome the limitations of the conventional titanium blade gear, which is not still enough and is vulnerable to plastic deformations under excessive torque. To investigate the basic characteristics of the proposed SMA mesh washer gear, a static load test was performed on the thickness of the SMA mesh washer and the rotation of the gear. Moreover, The microvibration measurement test demonstrated that the SMA mesh washer gear proposed in this study is effective for microvibration attenuation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.9
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• pp.784-793
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• 2017

A two-axis gimbal-type X-band antenna mounted on an observation satellite can efficiently transmit high-capacity image data to a ground station regardless of both the satellite position and the orbital motion. However, this X-band antenna induces unnecessary micro-jitter which can degrade the image quality of the high-resolution observation satellite. Therefore, to achieve the high-resolution image quality from the observation satellite, micro-jitters have been required to be isolated. In this study, to resolve aforementioned drawback, we proposed blade gear using a shape memory alloy (SMA) applied to azimuth stage of X-band antenna. To investigate the rotational basic characteristics of the proposed SMA blade gear, we performed rotational static loading test. Futhermore, to evaluate the cycle to failure of the gear, accelerated life test was conducted. The temperature test was conducted to confirm rotational basic characteristics at various temperature conditions. To verify the isolation performance for micro-jitter, we performed micro-jitter measurement test.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.1
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• pp.1-9
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• 2004

In this paper, an efficient modeling method of Horizontal-Axis Wind Turbine(HAWT) system is proposed. This method Is based on representing a HAWT system as a multi-body system with several rigid bodies i.e. rotor blade, low/high speed shaft, gear system, md generator. Also, simulation software WINSIM is developed to evaluate performance of wind turbine system. Simulation results show that the proposed modeling method and simulation software are efficient and reliable.

• 한국신재생에너지학회:학술대회논문집
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• 2005.11a
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• pp.244-252
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• 2005

석유 및 석탄 에너지의 고갈에 대비해 향후 지속 가능한 대체 에너지원으로 세계 각국은 다양한 에너지원의 개발에 총력을 기울이고 있으며, 그 중의 하나가 풍력 발전 시스템이다. 이러한 풍력 발전 시스템은 현재 단위 시간당의 출력 효율이 높은 MW급 시스템 개발이 주를 이루고 있어 단위 출력당 에너지 생산 비용이 높은 도서 벽지 및 독립 전원 지역용의 풍력 발전 시스템의 개발이 절실하다. 이에 본 과제에서는 향후 도서 벽지 및 독립 전원 지역에 활용 될 수 있는 100kW급 풍력 발전 시스템 개발 과정중 개념 설계 및 기본 설계 과정을 기술 하였다.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.5
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• pp.313-320
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• 2015

A 2-axis gimbal-type X-band antenna has been widely used to effectively transmit the high resolution image data from the observation satellite to the desired ground station. However, a discontinuous stepper motor activation for rotating the pointing mechanism in azimuth and elevation directions induces undesirable micro-vibration disturbances which can result in the image quality degradation of a high-resolution observation satellite. To enhance the image quality of the observation satellite, attenuating the micro-vibration induced by an activation of the stepper motor for rotational movements of the antenna is important task. In this study, we proposed a low-rotational-stiffness blade gear applied to the output shaft of the stepper motor to obtain the micro-vibration isolation performance. The design of the blade gear was performed through the structure analysis such that this gear is satisfied with the margin of safety rule under the derived torque budget. In addition, the micro-vibration isolation performance of the blade gear was verified through the micro-vibration measurement test using the dedicated micro-vibration measurement device proposed in this study.