Posted on: November 02, 2010, 05:31:48 PMPosted by: SpmP
Can I build locally with price comparable to buying one in from China is the mission
Unless you get a lot of stuff for free, and only pay yourself 10 cents per hour for your labor, you can't compete. On the other hand, building a wind turbine yourself is a rewarding endeaver that you cannot place a price on. This is just my opinion, based on building one and buying three. Others may have different thoughts on the subject.
Posted on: November 05, 2010, 12:57:09 PMPosted by: SparWeb
Did you forget the pictures I sent a few months ago? (Did you GET the pictures I sent a few months ago?)
No, I haven't forgotten those pictures, but it's true that I only found them and my other PMs about two months ago. I've been meaning to thank you for the pictures and also respond with a few thoughts of my own. I wish you would post those pictures so that everybody on the forum could see them, but I understand and respect your reason for not posting them.
For the benefit of other readers who haven't seen the pictures, they showed a 5 kw Exmork wind turbine still mounted at the top of its tower, with its tail boom lying on the ground, and all three of its rotor blades busted in half. The inner halves of the blades were still mounted on the wind turbine rotor hub, and the outer half of each blade was lying on the ground, in close proximity to the tail, at the base of the tower. There was no picture showing where the detached parts had landed originally.
My analysis of that failure is that it was caused by faulty installation and lack of proper maintenance. The manufacturer Exmork was also partly to blame. Here's how I arrived at that conclusion.
There are six 14 mm diameter Allen head capscrews that bolt the tail boom to the alternator housing casting. These bolts are approximatelu 2 1/2 inches long, and they are arranged in an approximately elliptical bolt pattern of approximately 4 inches by 6 inches size. Although Exmork furnished the bolts and FLAT washers with the turbine, they INCREDIBLY did not furnish LOCK washers. (This was the case with my three Exmork wind turbines, so I feel fairly confident that it was also true with the 5 kw in the pictures). It appears that the installer who installed the tail boom on the failed 5 kw apparently didn't have enough mechanical savvy to realize that those cap screws needed lock washers. After four, maybe five of the cap screws vibrated loose or maybe even fell completely out, the remaining cap screw(s) snapped in the storm that wrecked the turbine. If you look closely at the pictures you can still see one broken cap screw sticking out of the alternator casting. Had all six of those cap screws remained tightly fastened, there is NO WAY that the tail boom would have come off. Even as few as four of them would hold it in anything less than a Category 5 hurricane.
After the tail boom came loose, it swung into the path of the rotor blades and broke all three of them.
I do partially blame Exmork for not providing lock washers. Further to their discredit, they also did not provide lock washers for the bolts that are used to assemble the rotor blades onto the rotor hub. And lastly, the "Jesus" nut that holds the rotor hub onto the tapered alternator shaft was provided with a flat washer, but no lock washer. And it was just a plain nut, not a castellated nut. There was no hole drilled in the shaft for a cotter pin. These inexcusable omissions undoubtedly contributed to this wind turbine failure. However, any mechanic worthy of the name should have caught them during the installation process. I believe primary blame is on the installer.
Proper maintenance procedures could also have prevented this tragedy. The wind turbine should have been lowered after six months and somebody should have checked all the bolts. People still think they can raise 'em and forget 'em. Taint so with wind turbines, as anybody who has read the Dan's book would know.
poco
