Entrepreneur Proposes Wind-Turbine Gear Factory For Indiana

September 12, 2011 by Windpower Engineering
Filed under Turbine Design, Wind Turbine Gearboxes

You might think the U.S. has lots of gear-making capacity, so why would a start-up envision a factory capable of more of the same? The answer lies in the size of the gears planned by Vela Gear Systems CEO Noel Davis. Gears required in the wind industry can be in excess of 6 ft in diameter, while gearboxes weigh up to 20 tons. In addition, the nation has more than 30,000 utility grade wind turbines, where every year more approach the end of their warrantees and some near retirement. This means many may need gearbox repairs or replacements.

Davis and his colleagues are well acquainted with wind turbine gearboxes. He ticks off the types that will need repair and possibly replacement: “A planetary gearbox for a typical 200-ft high 1.5-MW wind turbine weighs more than 15 tons. Its sun gear has about a 24-in. diameter and 5-ft length, three planet gears each with about a 30-in. diameter. The ring gear has about a 70-in. diameter while spur or helical gear easily have 40-in. diameters. The output pinion driving the generator can weigh a hundred pounds. There are also smaller gear drives that pitch the three blades to catch the wind, and azimuth drives to rotate the entire 100-ton nacelle to face the wind.” None of these large slewing rings and gearboxes are small enough to be handled at the more frequently encountered automotive gear facilities.”

What’s more, says Davis, main-drive gearboxes have individual components that may weigh up to 10,000 lb, and when assembled, 20 tons. These components cannot be lifted by hand and require lifting equipment and an overhead clearance beyond what is available in most automotive-component facilities. Lifting large components, such as 6-ft diameter gears in and out of machine tools, then assembling them into a 20-ton gearbox, and then onto a flatbed truck for transport, requires a taller gantry cranes than those at most facilities. And the next generation wind turbines are just getting bigger. In the end, Davis sees a purpose-built facility just for wind-turbine gears.

Noel Davis

But where to build? Davis starts sketching a Venn diagram with three circles in North America: the location of wind farms, the location of raw material, and the location of the skilled labor. “Wind farms are mostly in the middle of the Midwest. Steel comes mostly from the areas spanning Milwaukee to Pittsburgh, and skilled machinists needed for this business are found in automotive manufacturing states. These three circles intersectd in Indiana, an ideal location for this business,” he says. Marion, Indiana to be specific.

Davis also has ideas for financing this ambitious venture. “I have some money from the sale of a previous company that I have put up. The Chamber of Commerce for Marion has also secured a hundred million dollars in bonds. But those convert only if we can drum up enough business to fund the debt of the bonds.”

He figures that his skilled workers will earn $23 per hour with a fully burdened rate of $40 per hour, while Europeans are importing this product at $60 per hour plus ad extra 15% of the total cost for ocean freight and logistics to North American wind farms from European manufacturing sites. Bottom line is that a promise from OEMs to build about 20 gearboxes each year will be the minimum needed to secure the bonds. Soon after that, Davis sees groundbreaking on the new factory, laying the foundation, ordering the machine tools, and hiring the staff.

Washington is fond of patting itself on the back for its gutsy calls, that in hindsight, are not terribly difficult. Building a new factory in American is the real gutsy call.

WPE

Tags: gears, Vela Gear Systems, Wind Turbine Gearboxes, windpower

Re-building a better gearbox

February 28, 2011 by Paul Dvorak
Filed under Maintenance, Wind Power News, Wind Turbine Gearboxes

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Broadwind's modular test rig is capable of full-load testing up to 3 MW.

As OEMs build larger wind turbines, they push the bounds of what’s possible for a 20-year service life. Occasionally, the boundaries push back with failures, often of gearboxes. Technicians at Broadwind Services, a division of Broadwind Energy in Abilene, Texas, say they can fix those broken gearboxes and make them better than new in a recently opened a 60,000 ft² facility.

The facility will disassemble, remanufacture, and do full-load testing on large wind turbine gearboxes. “We made upgrades to the overhead cranes, tooling, and equipment for the work cells that will do disassembly and reassembly,” says President of Broadwind Services Paul Seppanen. “An impressive test bench allows full-load testing up to 3 MW. It’s modular so it can handle the full range of gearboxes that are installed in turbines,” he says. Gears that need regrinding and replacement will be shipped to Broadwind’s gearing facility in Chicago.

Broadwind cutting big gears smaller 300x200

Broadwind's Seppanan says worn gearboxes can be remanufactured to better than new conditions.

The company says its plan is to put back a better gearbox than it took out. “We can figure out why it failed, and look for the next revision of bearings, for instance, because those manufacturers are constantly innovating as well. Also, wind-gearbox OEMs are making multiple versions of their boxes, sometimes they have a model number that ends in -3 or -4. We can remanufacture an early gearbox version, upgrading it to a later specification, or even beyond the specification of the most recent version of the box. “Proprietary techniques such as superfinishing the gears so they mesh better, improved lubrication equipment, and a range of other enhancements will extend the life of the gearbox,” he says.

Seppanen says root-cause analysis is a core competency at the facility. The company has been inspecting and remanufacturing gearboxes for eight years in the U.S., mostly on the kW scale. “That experience will be put into MW gearboxes,” he adds

Some failures are caused by manufacturing defects, some come from loads and fatigue over the design life, and a small number just fail early. “Many wind turbines have stretched the limits of their gearboxes and in some cases loads they see are beyond what they were designed for. Originally, gearboxes in smaller turbines would run smoothly without substantial failure frequency over their working life.”

Analysis starts in the field often before a gearbox completely fails. Teams will be up-tower with borescopes looking inside the gearbox and using condition or vibration monitoring equipment to diagnose what might be going wrong. That data goes back to the shop for the team that will tear it down. Then working back through a chain of events lets the repair team understand the root cause. We might find damages to a gear or shaft but we know that what really led to that was the bearing that failed early. Experienced engineers will make the analysis. Remanufacturing the gearbox will solve the root-cause problem so when the gearbox goes back to the field it will run longer on its second life.”

Some owners carry a pool of swap boxes. “Part of the company strategy is to also build a pool of spare boxes. When an owner with a turbine down contacts us for one, we’ll sell the spare box to the owner and buy back the damaged “core” in exchange. In the ideal mode, the truck that takes out the remanufactured box hauls back the damaged unit,” he says.

Tags: Abilene, Broadwind, gears, Wind Turbine Gearboxes