• New & Renewable Energy
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• v.16 no.4
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• pp.23-32
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• 2020

The wind turbine gearbox has the longest downtime among other major turbine components such as blades, generators, and main bearings. Therefore, gearbox manufacturers conduct rig tests to evaluate conformity in terms of design and function. Rig tests, however, have limited similarity compared with atmospheric wind turbine operating conditions. Rig test conditions are thoroughly controlled and maintained by testers and the component certificates of gearboxes issued through the test cannot fulfill wind farm operator's requirements. Hence, certification bodies such as DNV-GL and UL require a mandatory gearbox field test report for type certification. The Korea Energy Agency (KEA) also introduced gearbox field test as a part of the KS type certificate in 2016, although it is optional . In this paper, gearbox field test procedures and requirements are introduced, and the first domestic application case of the test is reported. The field test was conducted with a 1.5 MW wind turbine gearbox located in Jeju as the test object.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.311-315
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• 2012

In these days, promising renewable energy, wind turbine is clean energy but has an environmental pollutant which is noise. Noise assessment is one of the major performance evaluations for wind turbine and nowadays, developing and research for measurement and method of the assessment considering environmental pollutants is being important. Object in this study is that figuring out sound power characteristic of the gearbox for wind turbine through measuring sound intensity. In back-to-back test, we can figure out the noise characteristic of the gearbox for wind turbine through comparing and measuring sound pressure level, sound power level in operating at the each load condition respectively.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.249-252
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• 2006

Wind turbine gearbox is a complex mechanical system that includes gear trains, shafts, bearings, and gearbox housings. All these component are interacting with each other therefore changing certain design parameter will affect other components. RomaxDesigner enables a reduction in development period by simulating the full gearbox system. The gear pairs, bearings and shafts are represented as analysis objects and the complex components are modelled by means of reduced stiffness matrices. The software allows durability analysis and advanced contact analysis including the effects of system misalignments in gear and bearing. In this paper the 2MW wind turbine gearbox was model led and a study on optimum design was conducted

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.12
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• pp.1718-1723
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• 2015

The diameter of the rotor of 2MW wind turbine is being developed by a number of companies with more than 80m, reliability and economic efficiency of the wind power generator has been improved. The need for large-scale wind turbine with excellent economy has been attracting attention because the new orders and the location of the wind turbine market has reached a limit. Technology development for enlargement of wind turbine is possible not only the improvement of energy efficiency but also reduce the construction costs per unit capacity. However, mechanical gearboxes used in wind generators have problems of wear, damage, need for lubrication oil and maintenance. Therefore, we want to configure the gearbox of a large-scale wind turbine using a magnetic gear in order to solve these problems of mechanical gearbox.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.178.2-178.2
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• 2010

The wind turbine gearbox is important rotating part to transmit torque from turbine blade to generator. Generally, gear shaft which rotates causes vibration by influence of stiffness and mass with gear shaft. Root cause of this vibration source is well known to gear transmission error that is decided from gear tooth property. Transmission error excites a gear, and makes excitation force that is vibrated shaft. This vibration of shaft is transmitted to gearbox housing through gearbox bearing. If the resonance about which the natural frequency of the gearbox accords with shaft exciting frequency occurs, a wind turbine can lead to failure. The gearbox for wind turbine should be considered influence of vibration as well as the fatigue life and its performance by such reason. The cause to vibration should be closely examined to reduce influence of such vibration. In this paper, the cause of the vibration which occurs by a gearbox is closely examined and the method which can reduce the vibration which occurred is shown. It is compared with vibration test outcome of a 3MW gearbox for verification of the method shown by this paper.

• 한국신재생에너지학회:학술대회논문집
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• 2005.11a
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• pp.693-697
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• 2005

This study was performed to develop accelerated life test method of the wind-turbine gearbox using accumulated damage theory that used to model the fatigue of parts that receive variable load. The accumulated damage theory was introduced, and the estimation of life and calculation of accelerated life test time was illustrated. As the actual application example, accelerated life test method of the gearbox was described. Life distribution of the wind-turbine gearbox was supposed to follow Weibull distribution and life test time was calculated under the conditions of average life (MTBF) 140,600 hours and 99% reliability for one test sample According to the accumulated damage theory, because test time can shorten in case increase test load, test time could be reduced by 1.2 years when we put the load 1.2 times of rated load than 0.93 times of rated load that is equivalent load calculated by load spectrum of the wind turbine. This time, acceleration coefficient was 21.3. This accelerated test method was used to develop accelerated test method of gear reducer, gear and bearing as well as the industrial gearbox and it is considered to be applied comprehensively to mechanical parts the fatigue of which is happened by load or pressure etc.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.387-390
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• 2007

The gearbox for wind turbine have been increased the size by the wind turbine is needed to produce bigger power. The optimal sizing for gearbox is demanded because of limited space on the nacelle. The volume and weight for the gearbox are influenced especially for size of it. Therefore, the purpose of this study investigates the design characteristics considering types of gear train structure for optimizing the volume and weight of the gearbox.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.2
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• pp.109-117
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• 2014

This paper reports a method to modify the gear tooth profile of a wind turbine gearbox to reduce the noise caused by the impact of the gear teeth. The major causes of tooth impact are the elastic deformation of the gear teeth, shafts, and case of the gearbox under loading, and the fabrication tolerances in gear manufacturing. In this study, the tooth profile was modified considering the elastic deformation of the gear tooth and the tooth lead modification to compensate for tooth interference in the lead direction as a result of shaft deformations. The method was applied to the gearbox of a 2.5MW wind turbine, and the transmission error was characterized before and after modifying the gear teeth. For the modified gear teeth, the transmission error (67.6%) was lower by 17.8%. Additionally, the gear contact stress was reduced by 6.3%, to 22.3%.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.5
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• pp.514-520
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• 2015

The effects of suspension stiffness on the reaction load of the gearbox suspension for a three-point suspension wind turbine drive train were investigated by finite element analysis. The reaction forces of the gearbox suspension appear to increase as the gearbox suspension stiffness increases; however, the main bearing stiffness has a reverse effect on the reaction forces. The influence of the gearbox suspension stiffness is greater than that of the main bearing. Since the suspensions must provide the gearbox with proper support, it is not practical to use soft gearbox suspension for small reaction forces. It is more feasible to use stiff main bearings. As a guideline for the main bearing stiffness in the present study, we propose a relative stiffness of 100-150% of the reference.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.391-394
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• 2007

Wind turbine gearbox is a complex mechanical system that includes gear trains, shafts, bearings, and gearbox housings. All these components are interacting with each other therefore it is important to assess the whole performance by considering the individual component design. In this paper, the performance assessment of 2MW wind turbine gearbox was conducted under various operating conditions at test bench and test result was compared with the design calculation.