One passionate proponent of condition monitoring systems (CMS) for the wind industry is David Clark, sales director for Turningpoint, a New Zealand-based maker of vibration-based CMS that sells more systems in North America than all its competitors combined.
Clark is convinced that vibration CMS are the best answer to an industry that has long struggled with catastrophic gearbox failures and expensive repairs. Finding such problems - and finding them early - can provide months of lead time for up-tower part replacements that might cost $30,000, versus full-blown repairs that require removing a gearbox and cost hundreds of thousands of dollars.
"It can pick out bad bearings, bad gears, misalignment and balance, mechanical looseness - there's a myriad of things that it can pick out," Clark says of vibration monitoring. "There are things that it finds that no other method does." And that, he adds, sets vibration CMS apart from methods that involve examining oil for increasing numbers of metal particles.
Overall, Clark believes that North Americans have been slow to embrace CMS because, in its early years, the US wind industry was given tax credits for merely planting turbines, not for actually producing 20 years of power. It is only recently that the US wind industry has become increasingly populated with executives from industries, such as oil and gas or heavy manufacturing, where CMS has long been accepted as essential.
Clark believes CMS is especially important on new turbines. "I just talked to somebody who had nine out of 20 gearboxes that failed in the first three months," he says, "and that all falls under the manufacturer's warranty." But predicting failure near the end of warranty periods, as well as around the end of a turbine's 20-year life cycle, is also vital. "Nothing runs better in year 18, 19, 20 or even seven, for that matter, than it did in the first two years," Clark says. "CMS benefits both the manufacturer and the owner, but it's just that point of who's going to pay for it is where people usually have a hang-up."
Although Clark's company provides factory-installed vibration systems for American-made Clipper 2.5MW machines, Clark doesn't believe turbine makers adding CMS as standard equipment is a likely overall solution. "It doesn't behoove manufacturers to tell you what's wrong with their product," he says, adding that turbine makers fear such statistics could lead to extensive recalls.
Clark concurs with estimates that suggest only 10% of domestic turbines use CMS. But he believes the tide is turning, especially as turbines get larger and the cost of repairs goes up. Using CMS and knowing what needs to be fixed before it fails lets the industry perform maintenance on its own terms, he insists. That means expensive crane call-outs can be coordinated around multiple repairs and, significantly, it also means repairs can be targeted to low-wind seasons.
"You wait until the turbine breaks and react to the maintenance that way," Clark says, "or else you predict maintenance. That's what we do. And virtually every other industry, save for wind turbines, uses that same technology."
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