Technical school for wind techs is usually about 18 to 24 months. But you can’t learn everything in a classroom. Sometimes you have to climb a tower, many towers. And that is good way to learn. But after a few years out of the classroom, it’s a good idea to come back and find out from other techs what they have learned and what might be available in the aftermarket that would be useful keeping a turbine working longer between scheduled shutdowns. That is the purpose of WindTech 2012.
Even for non techs like me, the two-day event was a great opportunity to mingle with wind techs and component suppliers to the wind industry to find out what’s new. Here’s a little of what I learned:
- 1. Oil analysis can tell a lot about the lubricant in a turbine gearbox. Sending a few ounces of oil (taken from a tap before the filter) to a lab can reveal a range of contaminants and chemicals that were not originally in the oil. Castrol’s Ted Vasiliw showed a sample report and guided the class through it. The reports are generated by spectrograph so it reveals in detail what should and should not be there. For instance, in the Midwest, nitrogen often shows up because fertilizer blows up from the farm fields.
- 2. Safety factors are dropping off as turbines get larger. The factors are the indicators of “over-design” that goes into many products to protect against heavy use. Early turbine often had factor of safety of close to 2, and although they were only 225-kW machines, their transmission would last 10 year and more before serious wear. Turbines a few years later with 660-kW capacities were built with safety factors close to 1.5. More recent designs are right on the knife edge of 1.0. This makes it difficult to say that newer machines will be more reliable. This is not carelessness on the part of OEMs, but rather the tradeoff to excess weight. On the plus side, it will keep wind techs busy for many years.
3 Gearbox failures still plague the industry. One tech told of a neglected gearbox that became so jammed with debris, it seized up so the high rotor torque sheard the gearbox mounting bolts and twisted it 180°. On the up side of this, David Clark told of the success of condition monitoring equipment. Once installed, the vibration signals and the analysis it generates can tell which bearing or gear is going to need attention, and in sufficient time to make the repair a three day uptower task, not a gearbox replacement and costly crane callout.
4. Safety procedures must never sleep. Safety consultant Todd Shelton tells of the time a slip-ring circuit was “off” but still live. H touched it without first testing the circuit with a voltmeter, so it touched him back. His message: Work in teams, and don’t ever touch a circuit without first testing it with a voltmeter. Never.
5. I can repair a bullet hole in a rotor blade. Lou Dorworth with Abaris Training showed us how along with fixing lightning strikes and leading edge erosion. The bullet hole first requires deeply sanding down the circular area and then building it back with several layers of fiberglass material, each about one inch larger than the last.
- 6. Lastly, hands-on demos with techs from Sika and Mankewitz materials showed how to mix coatings that would finish a repaired and sanded blade. Each coating has a different color, and cures in about 45 minutes so that you could roll on a 12 m section and then start over with the follow-on coat. The materials are all two-part coatings with about two-hrs of pot life. And on cold days, about 2 oz. of thinner makes the material easier to apply.
All the classroom sessions were great experience and confidence builders. More WindTechs are planned for 2013 at several locals around the country.
Filed Under: Events, News, Towers, Training