Wind Turbine Gearboxes
Articles About Wind Turbine Gearboxes
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A critical problem for wind turbine gearboxes is failure of rolling element bearings where axial cracks form on the inner rings. This article presents field experience from operating wind turbines that compares the performance of through-hardened and carburized materials. It reveals that through-hardened bearings develop WEA/WECs and fail with axial cracks, whereas carburized bearings do not. The field experience further shows that a carburized bearing with a core having low carbon content, high nickel content, greater compressive residual stresses, and a higher amount of retained austenite provides higher fracture resistance and makes carburized bearings more durable than through-hardened bearings in the wind turbine environment.
In order to analyze the different gear oils suitable for the lubrication of wind turbine gearboxes, five fully formulated ISO VG 320 gear oils were selected. In between the selected gear oils, four PAO base oils can be found: PAOR, PAOM, PAOC and PAOX. A mineral-based oil (MINR) was also included as reference.
In recent years the estimation of gearbox power loss is attracting more interest â” especially in the wind turbine and automotive gearbox industry â” but also in industrial gearboxes where heat dissipation is a consideration as well. As new transmissions concepts are being researched to meet both ecological and commercial demands, a quick and reliable estimation of overall efficiency becomes inevitable in designing the optimal gearbox.
Prototype and Process Development Ensuring Stable Quality at the Highest Level
The growth of worldwide energy consumption and emerging industrial markets demands an increase of renewable energy shares. The price pressure coming from coal, oil, nuclear and natural gas energy - combined with enormous worldwide production capacities for components of wind turbines - make wind energy a highly competitive market. The testing and validation of gearboxes within the test rig and the turbine environment attract a strong focus to the needs of the industry. The following contribution sums up the typical process requirements and provides examples for successful system and component verifications based on field measurements.
The chemical and physical properties of gear oils may change, depending - more or less - upon their formulation and the environmental conditions under which they are used. This is why - after three years of use in a wind turbine - a gear oil was examined to determine if indeed changes were evident and if the protection of the gears and rolling bearings still met the same requirements as would be expected of fresh oil. Our findings revealed that the existing gear oil - as well as its ability to protect the gears and rolling bearings - had degraded very little compared to fresh oil.
The proof of the reliability of a gear drive is now an additional requirement. In Europe, the acceptance authorities for wind turbines are requesting a system reliability proof from gearbox manufacturers. The AGMA committee reviewing the AGMA 6006 standard for wind turbines is considering adding a chapter about design for reliability. However, reliability considerations are not new; NASA, for example, was in the 1980s using reliability concepts for gear drives.
Th e signing of a contract for more than 5,000 sets of SKFâ™s latest high-capacity cylindrical roller bearings (HCCRB) for wind turbines will impart added load-carrying capacity, more reliability and longer life to the Nanjing Gear Companyâ™s (NGC) line of gearboxes for wind generation applications.
The Department of Energy estimates that 4 million megawatts of potential powerâ”four times the amount all U.S. power plants combined currently produceâ”exists in offshore wind energy. Construction of Americaâ™s first offshore wind turbines began in July. The wind farm, which is being constructed off the coast of Block Island, RI, will consist of five turbines. Together, they will produce 30 MW.
Coming off of a stellar 2017 for the wind power industry, Wind Power 2018 is all about carrying that momentum forward.
Wind is a form of solar energy. Winds are caused by the uneven heating of the atmosphere by the sun, the irregularities of the earthâ™s surface, and rotation of the earth. Wind Turbines convert the kinetic energy in wind into mechanical power.
One of the largest components manufactured by Schaeffler last year was a double-row tapered roller bearing featuring an outer diameter measuring 3.6 meters and a weight just over nine tons.
After a sluggish 2013, annual installations of new wind turbines grew by 44% in 2014, according to the Global Wind Energy Council. And while much of that growth has been in Asiaâ” particularly China, which now leads the world with 114 GW of installed capacityâ”the USA, Europe, and the rest of the world expect steady growth for the next couple of years as well (Fig. 1).
LEGO & Vestas Collaborate on Sustainability Project.
Wind turbines are getting bigger than ever, and the manufacturing infrastructure that facilitates their construction needs to start growing with them.
For a 5-megawatt wind turbine prototype, aerodyn employs the latest control and software technologies, including a comprehensive PC-based control solution and the new modular TwinCAT Wind Framework. The TwinCAT Wind Framework features the latest software engineering and Big Data applications to extend current Industry 4.0 concepts to the wind energy industry. The modular software supports, for example, the direct provision of sensor data to the operatorâ™s database, and in general enables the easy adaption of the wind turbine operation management to future requirements.
Wind turbine gearboxes are subjected to a wide variety of operating conditions, some of which may push the bearings beyond their limits. Damage may be done to the bearings, resulting in a specific premature failure mode known as white etching cracks (WEC), sometimes called brittle, short-life, early, abnormal or white structured flaking (WSF). Measures to make the bearings more robust in these operating conditions are discussed in this article.
U.S. wind turbine growth puts a new spin on bearing manufacture.
A Q&A with N.K. Chinnusamy, president of Excel Gear of Roscoe, IL.
The latest developments for wind turbines from Voith Wind rely on proven technologies.
Despite posting its slowest quarter since early 2007, AWEA remains optimistic that the wind industry can and will work successfully with the revolving doors in Washington.
Modern drivetrains with voltage-source inverters not only offer advantages like, for example, variable speed operation, increased efficiency and higher dynamics, but also an increase in failures caused by induced parasitic currents.
Gearboxes are important assemblies within mechatronic systems. During the design phase of such systems it is essential to know the gearbox behavior under consideration of dynamic interactions with its environment. Holistic system simulation helps the engineer to understand this and to improve, adjust, or optimize gearboxes and their application.
Standardized calculation methods such as ISO 6336 and DIN 3990 already exist to determine the load distributions on gears inside a planetary gearbox, but by their very universal nature, these methods offer varying results depending on the gearbox design. Double helical gears, in particular, can benefit from more specific, complex algorithms to reach a maximum level of efficiency. Double helical gears interact with the rest of the gearbox differently than helical or spur gears, and thus benefit from different analytical models outside the standardized methods. The present research project describes the algorithm to determine the load distribution of planetary gearboxes with double helical gears.
For the lubrication of open gear drives used in different industrial applications such as cement and coal mills, rotary furnaces, or where the sealing conditions are difficult, semi-fluid greases are often used in preference to fluid oils. For girth gear applications the greases are used with a splash or spray lubrication system. The selection of such greases influences pitting lifetime and the load-carrying capacity of the gears, as well as wear behavior
As gear efficiency is improved in small steps, it is important to be able to distinguish actual improvements from scatter that can occur while testing. An FZG back-to-back gear test rig was used to investigate how the assembly and re-assembly of the same test setup affects the measurements. A spread in torque loss between one assembly and another of the same test setup were observed. Rig conditions also affected the spread in input torque. With knowledge of how the spread in torque loss varies due to assembly, test results could be distinguished between changes due to assembly and actual differences between tests.
Gearing is an essential component in conveyors. The material handling industry appears divided between those who favor high-end three-stage helical bevel gearboxes and those who rely on less expensive worm gearing. But thereâ™s an often over-looked alternative, the two-stage helical bevel gearbox.
The performance of high-speed helical geartrains is of particular importance for tiltrotor aircraft drive systems. These drive systems are used to provide speed reduction/torque multiplication from the gas turbine output shaft and provide the necessary offset between these parallel shafts in the aircraft. Four different design configurations have been tested in the NASA Glenn Research Center, High-Speed Helical Geartrain Test Facility. The design configurations included the current aircraft design, current design with isotropic superfinished gear surfaces, double-helical design (inward and outward pumping), increased pitch (finer teeth), and an increased helix angle. All designs were tested at multiple input shaft speeds (up to 15,000 rpm) and applied power (up to 5,000 hp). Also two lubrication, system-related, variables were tested: oil inlet temperature (160â“250° F) and lubricating jet pressure (60â“80 psig). Experimental data recorded from these tests included power loss of the helical system under study, the temperature increase of the lubricant from inlet to outlet of the drive system and fling-off temperatures (radially and axially). Also, all gear systems were tested with and without shrouds around the gears.
Gear drives focus on longevity, quality and customization.
Schaeffler Touts System Solutions and Electrification Advancements at Detroit Symposium
How one gearbox manufacturer took an existing design and transformed it to meet the needs of this demanding environment.
Worm, bevel, and parallel shaft gear units were installed at two breweries to provide the necessary process control.
With the increasing mechanical power capacity of gearboxes, the thermal power limit tends to become the limiting factor. To achieve a balanced system, the gear unit needs extra cooling. Using a fan that is mounted to a fast rotating shaft is a common solution. For this solution an optimal design is investigated.
In the general context of the reduction of energy consumption and polluting emissions, gearbox efficiency has become a major issue.
In this paper, the models for different power loss sources in transmissions from literature are applied and compared, which form the two methods - ISO 14179-2 and the joint model to estimate the power losses in a transmission. A 2-speed transmission in an electric vehicle is used as a case study to compare the two methods and validate them with experimental data.
In this study, a finite volume CFD simulation model of a single-stage injection-lubricated test gearbox was applied to investigate its oil flow and no-load power loss. The results provide physically plausible information on the oil supply and its distribution.
The U.S. Space Shuttle fleet was originally intended to have a life of 100 flights for each vehicle, lasting over a 10-year period, with minimal scheduled maintenance or inspection. The first space shuttle flight was that of the Space Shuttle Columbia (OV-102), launched April 12, 1981. The disaster that destroyed Columbia occurred on its 28th flight, February 1, 2003, nearly 22 years after its first launch.
Approximately one quarter of all servo motors around the world require some type of gear reduction in their applications. From large satellite dishes to precision medical devices, gearboxes boost torque and reduce speed for servos in order for them to be sized more efficiently. While gearbox fundamentals haven't changed much over the past 20 years, their effectiveness has improved significantly, driven mostly by the need to accommodate advancements in servo technology.
The Magnetic Gearing and Turbine Corp. (MGT), founded by Australian inventor Andrew French in 2000, manufactures injection molded gears and couplings based entirely on magnetic technology. The repulsive magnetic forces are used to transmit power without losing any energy, and drive shafts rotate completely independently of each other.
After getting positive feedback on changes made to the show last year, AWEA Wind Power is doubling down and taking their ongoing transformation even further.
A look at recent installations, plus interviews with some wind industry insiders.
The complete Product News section from the February 2010 issue of Power Transmission Engineering.
Does the U.S. renewable energy solution lie offshore? An update on the status of offshore wind projects.
The first trade show dedicated specifically to small and community wind took place in Detroit, Michigan November 3â“5. Denise Bode, American Wind Energy Association (AWEA) CEO, was pleased with the turnout for the event and the increasing potential for this segment of the wind energy market.
Calling on engineers and maintenance power plant personnel, industrial users of low- and medium-voltage motors and generators and motor repair shop staff...
Wind is the talk of the town. It has become especially relevant to the power transmission community where bearings, gears, couplings, motors and gearboxes are providing the equipment for this thriving alternative energy industry. It comes as no surprise that the Windpower 2009 Conference and Exhibition, arriving in Chicago from May 4â“7, will be the largest gathering of wind energy professionals and technologies to date.
In the late 1940s, the U.S. auto industry started an exciting experiment and spent decades on it. One result came in '63, when the Turbine was introduced by Chrysler Corp., now a part of Fiat Chrysler Automobiles (FCA). In appearance, the two-door, four-passenger car looked like a regular car, but it wasnââ‚¬â„¢t. Under its sleek shell, the car had a jet engine.
With today's smaller, hotter - and overloaded - machinery, specifying the correct lubricant is vital.
In most applications, gearbox reliability is critical to the productivity of the overall plant operation. So it follows that when industry is looking at the best ways to increase efficiency, reduce downtime, and increase profitability, gearbox performance and reliability are key factors. Designing for repair, and writing effective repair procedures, can speed the service time, and provide a quality refurbishment. The best practices listed in this article are proven, effective methods used to install and remove bearings, seals, gears, couplings and shafts within a gearbox.
Engineers typically learn that the bearing L10 life can be estimated using the so called âœC/P methodâ â” or the âœbasic rating lifeâ of the bearing, a method rooted in the 1940s. Major developments have since led to the âœmodified rating life,â released in ISO 281:2007, which includes the aiso life modification factor. In this paper a succession of equations used for bearing life ratings are reviewed, and current bearing life rating practices are discussed in detail. It is shown that â” despite the introduction more than 30 years ago of the adjustment factor of the basic rating life, and the standardization in 2007 of the aiso modification factor â” use of these improved calculation methods are not practiced by all engineers. Indeed â” many continue referring to the old model as a way of seeking compliance with existing, established practices.
Dave Soma, the mechanical supervisor at Leland Olds Station, a coal-fired power plant near Stanton, North Dakota, says he and his maintenance team care deeply about keeping the plant running and providing people electricity, especially in the dead of winter.
Our product focus includes the latest technology in gears and gear drives from the leading manufacturers.
Volatile aerospace market keeps gear manufacturers guessing.
The availability of high-strength shaft materials, in combination with bearings with high carrying capacity, allows use of slimmer shafts. However, the modulus of elasticity remains the same, so seat design for bearings and gears must be given close attention.
The improvement of the energy efficiency of industrial gear motors and gearboxes is a common problem for many gear unit manufacturers and end-users. As is typical of other mechanical components, the radial lip seals used in such units generate friction and heat, thus contributing to energy losses of mechanical systems. There exist today simulation tools that are already helping improve the efficiency of mechanical systems â” but accurate models for seal frictional losses need to be developed. In this paper SKF presents an engineering model for radial lip seal friction based on a physical approach.
News Items About Wind Turbine Gearboxes
1 GE Energy Partners with Chinese Co. To Develop Wind Turbine Gearboxes (April 22, 2006)
GE Energy and Nanjing High Speed & Accurate Gear Company (NGC) have agreed to jointly develop gearboxes for GE's 1.5-megawatt wind tu...
2 ZF Opens First U.S. Plant for Wind Turbine Gearboxes (October 4, 2011)
ZF Friedrichshafen AG has opened a plant for the production of wind turbine gearboxes in Gainesville near Atlanta, Georgia. As of 2012, t...
3 Bosch Rexroth Optimizes Wind Turbine Gearboxes (August 27, 2012)
The competitive pressure as well as the pricing pressure in the wind energy industry is mounting. If the sector wants to continue to expa...