The wind turbine was installed at RIT in early January. Since then, the turbine has only spent a total of two months setup producing power. The other two months it has either been awaiting parts or being repaired. Before this year, the turbine spent two six month periods in development testing without any issues. Why am I suddenly having all these issues? The answer is high winds. The turbine during development testing was in areas surrounded by trees sheltering the turbine from high winds. At RIT the turbine is on a hill, with a clear western exposure and the wind comes out of the west the majority of the time. This is great for performance, but I didn’t realize how much of a punishment it would put on the turbine.
Over the last four months I have had two tower failures resulting in the turbine crashing down. The first failure occurred when a storm with 40MPH winds blew through Rochester in mid January. This caused one of the 18” stakes which the guy wire attached, to be pulled out of the ground by the wind. To fix this issue I drove 6FT stakes 4FT into the ground which have yet to budge even in the strongest of winds. A couple of weeks later another storm rolled through, this time with 50MPH winds and the turbine yet again crashed into the ground. This time the wind tore out the eight, 4” screws which secured the base to the tower. This surprised me, since there should have only been a vertical force on the screws which would have been the weight of the tower and the turbine. I discovered that a horizontal force on the screws was the one responsible for the tower’s failure. I concluded that the top of the tower must have been staying because the nylon guy wires were not tight enough. The issue with nylon is that it stretches over time which results in the guy wires become loose and looser. To solve these tower issues, I bolted the wooden base to the tower instead of using screws. Additionally I replaced the nylon guy wires with steel cable which wouldn’t stretch. I used turnbuckles at the end of each guy wire which allows the guy wires to be easily tightened. The best part of the turnbuckles is that two people can lower the tower within a minute, whereas before one had to untie the nylon knots which was difficult in the sub freezing temperate of Rochester.
Two weeks ago, the strongest storm front of the year moved in. The winds were a constant 35MPH and gusted to 60MPH, which is approaching that of a tropical storm. To my delight the tower stayed standing, but the turbine had issues. The issue was that the blades and hub, fell off the turbine and were sitting at the base of the tower. What happened was that the two allen nuts on the arbor which hold the hub and blade to the generator’s shaft became loose. The wind pushed the arbor into the generator causing metal on metal contact. This resulted in the arbor machining through the metal around the motor’s shaft and caused metal shavings to enter the generator. The generator no longer spun smoothly and this along with the changing wind directions allowed the hub and blades to come off. To solve this issue, I lock tightened the arbor to the generator’s shaft, and any other parts that could become loose over time. I also cleaned rebuilt the generator and got it to spin smoothly again.
Overall, in the last four months I have learned a great deal about the project and made many improvements. The turbine and tower are now far more robust and should now be able to deal with the extreme winds that blow occasionally through Rochester.
