The good news was brief this weekend, on the windmill front. The weather was spectacular, and I'd been wanting to attend to what I thought was more loose plating material that had started last summer on one of our magnets. Unfortunately what I found was worse. It appears that corrosion formed behind the magnet and it has now loosened from the magnet plate and is actually shifted out of its intended slot in the magnet retainer ring. This caused a minor rub on the stator, which from the ground I had thought was just a piece of plating. In hindsight, or hind-hearing, if it were, I should have recognized the sound of this magnet ‘clapping' against the rotor plate at higher rpms. Fortunately it has been largely shut down for the summer months, so I don't think there was any permanent damage to the stator.
This the retainer, and how it should look:
Now, however, we've got a pretty sizable project. The turbine has got to come down, in whole or in pieces. I guess that is a pretty key first decision. I designed this alternator so that we could remove the blades, pull the stator, and take off alternator, leaving the head assembly and tail on the tower. This reduces the heaviest lift to about 135#, but it still is a fair challenge on the tower; probably more so putting it all back together. The easier method is to drop the whole unit, but that means a heavier gin and winch, or a crane… urgh.
On a positive note, the turbine has been up for almost six years now and has served us pretty well. I'm thinking it is probably an opportunity to do a few other things:
1) Check the other magnets
2) Replace the poly carbonate stator rings, improve how they are fitted to avoid cracks
3) Add a weather shroud of some sort to reduce rain/snow effects
4) Refinish blades, reduce blade noise
5) Repaint any exposed metal parts