Gearboxes have different physical qualities based on their type. Gearboxes for wind turbines are often built of steel, aluminum, or brass. Other materials may be utilized as well. Each type of wind turbine gearbox has its own distinct shape and characteristics. These details are critical to keep in mind for effective gearbox oil maintenance.
Planetary Gearbox
Planetary gearboxes get their name from their resemblance to the solar system. A solar gear, an annular gear, and planetary gears are all parts of a planetary gearbox. An annular cogwheel (anulus ring) is the outer ring with internal teeth, and planetary gears spin around the sun gears and the grid with the help of both the sun gear and the ring gear.
Planetary gearbox components are typically constructed of aluminum, stainless steel, or brass.
The efficiency of planetary gearboxes is extremely high. They have a high torque to weight ratio and a great shock resistance. They are also more stable than any other form of wind turbine gearbox.
When steel gears collide with other gears, they can make a lot of noise. They are also prone to wear due to their design. This necessitates ongoing and complex maintenance, as well as a sophisticated automatic wind turbine oil system.
Spur Gearbox
Spur gears are positioned on parallel shafts and feature straight teeth. This sort of gear can come in a variety of sizes and gear ratios to fulfill the demands of a specific speed and torque. Steel or brass are the most common materials for spur gears. Polycarbonate and nylon are two other common construction materials.
Spur gear allows for precise speed control. It produces a lot of torque. It’s important in wind turbines that need tight speed management and can even slow down if necessary.
A spur gearbox, like a planetary gearbox, can be noisy and wear out quickly. For this sort of gearbox, continual attention to the lubricating system is essential.
Bevel Gearbox
Straight and spiral teeth are the two types of bevel gears. Cast iron, aluminum, and other similar metals may be used. Bevel gearboxes are typically fitted with a perpendicular shaft in right-angle applications.
Helical Gearbox
Helical gears have a unique cut that enables for gradual and smooth contact between gear teeth. It operates in a rather quiet manner. Cast iron, aluminum, and iron are the most common materials used. Wind power facilities with large and efficient electrical performance can benefit from gearboxes that use helical gears.
Wind turbines operate almost silently thanks to helical gearing. They are also incredibly efficient and have a lot of horsepower.
Although the gear teeth in this location do not wear down quickly, there may be a significant amount of axle load.
Worm Gearbox
Worm gearboxes are employed in machines that demand a high rate of rotation and a large weight. Right-angle systems can benefit from worm gear. Worm gears are abrasion-resistant. They also produce very little noise.
This arrangement makes it simple and painless to service the equipment. Furthermore, this equipment is quiet and features a dependable functioning mechanism.
Worm gear’s only drawback is that it is inefficient. As a result, it’s only practical to utilize with low-capacity power plants that produce a tiny amount of electricity.
A windmill uses what kind of gears?
Gears and gear manufacturing: The performance and dependability of planetary gears inside wind-turbine power transmissions are harmed by uncontrollable and extremely fluctuating wind forces. In a planetary gearset, a couple of advancements can reduce rolling element maintenance and handle more load. The primary concept is to equalize gear loads, which reduces internal stresses and increases wind turbine reliability dramatically. The load sharing concept, which consists of a double-cantilevered pin supporting the bearing and gear, can be employed in open planetary gear systems. A cantilevered sleeve mounts to the free end of the pin, which is attached to a single carrier wall. The sleeve is where the gears and bearings are mounted.
The drive can carry up to 50% greater torque thanks to two opposing arrays of these bearings installed on a double-wall planetary carrier. Furthermore, the integrated bearing and gear structure has been reduced to allow more space for rolling parts, hence increasing the bearing system’s power rating. Coatings can be applied to the rolling and sliding surfaces for maximum durability. As a result, torque is spread more uniformly across many planet gears, and gear and bearing life is extended. Additionally, merging shafts, bearings, and gears into a single unit reduces weight and costs.
A gearbox is used in traditional turbine architecture to convert the slow, high-torque power in the main shaft to a faster rotational speed helpful to the generator. Three-stage gearboxes are commonly used in utility-scale wind turbines. A planetary drive is frequently used as the first stage since it is the best design for handling high torque. Helical gears are used in the final two stages.
Consider a 1.5-MW turbine operating at its rated output to get an idea of the torque generated by the rotor. 1.5 MW = 2,011 horsepower
Assume 15 rpm on the rotor based on the torque and speed connection. Using,
T / 5,252 = Php Where Php represents power (horsepower), rpm represents rotational speed (rpm), T represents torque (lb-ft), and 5,252 is a conversion factor.
That’s 700,000 ft-lb on the input shaft of the gearbox. Of course, a 1.5-MW turbine only operates at full capacity for a small percentage of the time.
The computation can make you wonder, “What are the loads on a gearbox?” Instead of a few numbers, gearbox designers use load cases, which are loads monitored over time by sensors on operational gears. As a result, loads are continually shifting. Consider the fluctuating loads that equipment receives on a tall tower swaying in the wind and subjected to temperature variations. A rotor shaft and gearbox will eventually become misaligned. Additional loads are placed on the gearbox and bearings as a result of this. The gearbox and generator are in the same boat. As a result of these conditions, gearbox problems are common, and the vehicle has a reputation for being unreliable. When a gearbox malfunctions, the turbine must be taken off line (out of production) while the gearbox is changed, which can be an expensive and time-consuming process.
Flexible shaft couplings compensate for modest misalignment between the output shaft of the gearbox and the generator shaft. Several designs have gained popularity. One steel-shaft coupling with a torque rating of up to 9,200 ft-lb is reported to be wear and maintenance free, operate quietly, provide electrical isolation, and be torsionally supple and flexible in all directions.
To build a double cardanic system, another concept uses two sets of links, one on each end of a tube. Rubber bushings join the connections together. It can be sized for any torque, requires no maintenance, is electrically insulated, dampens noise and vibration, and is flexible in axial, angular, and radial directions, according to the maker.
A fiberglass composite membrane and fiberglass tube are used in more modern designs. Axial and angular flexibility is provided by membranes at each end of the tube. It has a low weight, is maintenance free, electrically insulated, and torsionally robust, and is rated for torques up to 14,750 ft-lb.
What are the materials that wind turbine shafts are constructed of?
Growing environmental concerns, such as greenhouse gas emissions, are driving the wind turbine shaft industry. Manufacturers are likewise attempting to reduce costs while improving the production of wind turbines. Furthermore, rising energy demand is a result of rising population and rapid industrialization.
To satisfy rising energy demand, governments around the world are stressing the use of renewable energy sources such as solar and wind. This is projected to result in the construction of additional wind power projects, which will increase demand for wind turbine shafts.
The growing use of offshore wind energy generation as a clean source of energy in several countries, including China, Japan, South Korea, India, Taiwan, and the United States, is likely to open up new potential for the wind turbine shaft market. Harsh environmental conditions, on the other hand, necessitate greater technological innovation in terms of design and strength, resulting in a higher initial setup cost.
Improving economic conditions in numerous regions of the world, as well as lower per kWh wind energy generation costs, are leading to increased adoption of wind turbines around the world, which is likely to propel the worldwide wind turbine shaft market forward. However, the high capital and material costs of the turbine shaft may function as a market restraint.
Furthermore, solar panels are posing a threat to the wind turbine shaft business, as they compete with wind power generating. Manufacturers are focused on studying and designing the shaft with the ideal diameter and material to lower the cost of production in order to reduce the setup cost of wind turbines.
The shaft of a wind turbine can be composed of a variety of materials, including alloy steel, aluminum, and synthetic composites (like fiber glass). Fiber glass has gained popularity in recent years due to its light weight and strong tensile strength. Novel materials are being produced as a result of ongoing advancements and advances in the field of material science, and testing with new materials for wind turbine shafts is on the rise.
What is the weight of a wind turbine gearbox?
DOE is sponsoring initiatives that will build high-efficiency, lightweight wind turbine generators, all of which will use direct drive technology. Two of these generators are “superconducting,” which means they don’t utilize permanent magnets or rare earth elements.
Regardless of whether they’re direct drive or geared, these components are enormous (200320 tons for a 10-megawatt (MW) turbine generator system), and their placement on top of the wind turbine’s tower adds to the tower’s weight and expense. They also necessitate the use of huge, expensive cranes for installation and are difficult to move due to their weight.
Wind turbine tower heights have increased from 60 to over 80 meters, and are likely to exceed 100 meters (330 feet) in the next years, posing new concerns. At the same time, average wind turbine capacity have risen from 1 megawatt to 23 megawatts on land and 56 megawatts offshore, with projections for 1012 megawatt offshore wind turbines by the mid-2020s. This increase in capacity translates to more powerful machines that can generate more electricity, but it also translates to larger and heavier components.
Is it true that a wind turbine has gears?
In a wind turbine, a gearbox is frequently used to raise the rotating speed from a low-speed main shaft to a high-speed shaft connected to an electrical generator. Due to changing wind loads that are stochastic in nature, gears in wind turbine gearboxes are subjected to intense cyclic loading.
When it comes to wind turbine gearboxes, how long do they last?
Francesco Cornacchia believes that learning more about your wind farm can help you extend the life of your gearboxes from 20 to 25 years and maximize your investment returns.
Many wind turbine gearboxes are reported to have a design life of 20 years.
However, it is commonly known that many gearboxes do not endure the whole 20 years and fail early. What’s the deal with the discrepancy?
The solution resides in the definitions of gear and bearing lives. We can’t anticipate when a component will break, but we may estimate the likelihood that it will last for a certain amount of time.
A simple calculation demonstrates that if the projected life of each bearing in a drivetrain is added together to produce a “system level” life, the probability of one or more bearings breaking within 20 years is up to 93 percent. As a result, practically every gearbox in a wind farm is likely to break over the next 20 years. It may appear alarming, yet it isn’t far from the truth.
This result is based on a simplified calculation and is meant to represent the overall trend. We utilize more advanced versions of these technologies in our business to analyze and forecast failure rates. We can provide very precise predictions of drivetrain failures using design standards and simulations, as well as a large quantity of operational data and historical failure rates.
Wind farm owners and investors can benefit from managing this risk by increasing the value of their projects and reducing downtime. How are they able to achieve this?
It’s critical to pick the proper technology early on in the development process: the turbine must be suitable for the site characteristics (wind speed, shear, turbulence, wind farm design) and have a track record.
Investors must determine how design is affected by manufacturing procedures, as this can lead to significant uncertainty about the reliability of gearboxes made or remanufactured by various suppliers.
Major component supply chains must be considered: components that can only be produced by a single supplier can have a financial impact in the event of serial errors, manufacturing difficulties, or simply longer lead times.
Investors should also think about the quality of the maintenance. Even the best design in the world won’t last if best practices aren’t followed: we’ve seen turbines with large chunks of the lubricating system removed due to excessive alerts. This means that numerous components were operating without lubrication, resulting in expensive breakdowns.
Some technologies have well-documented and well-known design flaws. Technology evaluation and analysis are available.
That can provide you a clear picture of an asset’s future potential and operating expenses.
These issues should and can be solved during the wind farm’s commissioning sign-off phase. In the case of a retrofit during the installation of new technology. Premature failures can be considerably reduced if proper transit, storage, and installation procedures are followed.
With existing assets, these may be the easiest to affect. Component attrition rates, associated O&M costs, and revenue loss due to downtime will all be affected by best practice O&M processes and regimes based on data-driven CMS, SCADA, oil analysis, and other methods.
An in-depth asset health assessment and detailed examination of the assets’ historical data, as well as a full technology review of turbines and their primary components, will provide essential information on future potential and operating costs to any prospective investor.
Overall, the term “design life” might be deceiving, with overwhelming evidence indicating that most gearboxes in use fail in less than 20 years. The solution for investors is to use improved ways for identifying significant financial risks and reliability issues, which can be aided by working with a well-established partner.
If you want to learn more, come see me at the Financing Wind 2016 conference in London on October 27th, and we can talk about how Romax InSight’s software, solutions, and services can help your company.
What are the components of jet turbine blades?
The performance of the materials available for the hot section of the engine (combustor and turbine) was a limiting issue in early jet engines. The demand for better materials prompted extensive research into alloys and production procedures, resulting in a long list of novel materials and methods that enable modern gas turbines to operate. Nimonic, which was utilized in British Whittle engines, was one of the first.
In the 1940s, superalloys were developed, and in the 1950s, new processing processes like vacuum induction melting considerably boosted the temperature capability of turbine blades. Additional processing methods, such as hot isostatic pressing, improved turbine blade alloys and improved turbine blade performance. Nickel-based superalloys with chromium, cobalt, and rhenium are frequently used in modern turbine blades.
Aside from alloy advances, the development of directional solidification (DS) and single crystal (SC) production procedures was a notable breakthrough. By aligning grain boundaries in one direction (DS) or eliminating grain boundaries entirely, these technologies assist greatly boost strength against fatigue and creep (SC). Pratt and Whitney began SC research in the 1960s, and it took nearly ten years to deploy. The J58 engines of the SR-71 were one of the first DS installations.
Is it true that wind turbine blades are hollow?
The blades of commercial wind turbines are made of fiberglass with a hollow core, but aluminum and lightweight woods are also utilized.
How much steel does a wind turbine contain?
Steel alone accounts for 150 metric tons for reinforced concrete foundations, 250 metric tons for rotor hubs and nacelles (which house the gearbox and generator), and 500 metric tons for the towers in a 5-megawatt turbine.
What is the price of a windmill blade?
A typical rotor blade for a 0.75-MW turbine has a length of 80 ft to 85 ft (24m to 25m) and weighs around 5,200 lb/2,360 kg, according to some of the metrics provided for this market assessment. Blades are expected to cost around $55,000 each at this size, or $165,000 for a three-blade set. The amount of reinforcing grows in a logarithmic progression as the blades grow larger. Typical blades for a 1.5-MW turbine should be 110 ft to 124 ft (34m to 38m) long, weigh 11,500 lb/5,216 kg, and cost between $100,000 and $125,000 each. A turbine’s blades are around 155 ft/47m long, weigh about 27,000 lb/12,474 kg, and cost between $250,000 and $300,000 apiece when rated at 3.0 MW.
Using the aforementioned guidelines, wind turbine manufacturers produced around 441 million lb or slightly more than 200,000 metric tonnes of final blade structures in 2007. This makes wind turbine blade manufacturing one of the world’s largest single applications of engineered composites. Surprisingly, the astonishing volume in 2007 is about 38 percent more than in 2006 and nearly double that of 2005.
- 182 million lb Thermoset resins (mainly epoxy and vinyl ester) (82,550 metric tonnes)
The value of the blade market is sometimes calculated as a percentage of the market for turbines. Blades are thought to account for 15 to 20% of the total cost of a wind turbine. During 2007, the market for entire wind turbine systems was estimated to be somewhat more than $26 billion. Based on this, the composite blade market is anticipated to be worth between $3.9 and $5.2 billion. We believe that a more precise estimate of the composite blade market is $4.3 billion, based on current material prices and our estimates of production and overhead expenses (as previously mentioned). This represents a 43 percent increase over expected 2006 blade sales and a 114 percent increase over 2005. Blade producers should ship more than $5.9 billion worth of gear this year, based on predicted industry growth. This is a 38 percent increase in monetary value, while new installed capacity (MW) is predicted to increase by 26 percent. Although rising raw material prices (as petroleum and other chemical feedstocks become more expensive) can account for some of the disproportionate growth in blade value, product availability/shortages and the trend toward larger turbines with more expensive rotor systems are more relevant considerations.