I looked thru all my Picasa stuff and can't find the photos. I know they're there someplace.
Anyway, several years back I had 7.6 foot turbine that I was using to heat water with. I had it putting out around 2 kW on a regular basis, and the magnets left it. It had 1/4" thick wedge magnets in it that I got from Ed Lenz. They weren't pinned or retained in any way. Just glued with JB Weld and the rotors potted in resin. To this day I got Rare Earth Deposits in the field east of the house because I never found all the magnets from it.
After the magnets left it put a severe test to the blades. The blades didn't survive the test. I'm not sure if they clipped the tower or just broke. But all that was left was the root of the blades still bolted to the hub. One blade was sticking in the ground at the base of the tower and the other two were about 100 yards or so from the tower.
I was not around when it blew up. I came home and found it that way. Since then, I have NEVER built another wind turbine and just relied on epoxy or resin to hold the magnets on.
Edit: I had another one right in the shop once. I made a 8 foot rotor out of PVC blades. I was running it in the shop on a stand with no generator and blowing air on it with a pair of high speed 3 hp fans to see how fast it would run. One of the blades broke and put a hole in the shop ceiling. And then the stand tipped over and the other two shattered when they hit the floor.
My wife heard the explosion from inside the house, over the sound from the generator running, and she came running out to see what I had done this time. I believe my exact reply to her question of "What the HELL are you doing?" was, "PVC is not a suitable material for wind turbine blades........"
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Chris
