Following the summer slumber with our turbine - we have it furled for a good chunk of the summer - I was frustrated to find we had a
new noise. Generally no new noise is good noise. This was a audible mechanical clicking, or snapping occurring at less than a one per rev frequency a bit over cut-in, and growing in intensity as the rotor speed increased.
After ruling out any obvious contact points, I started to focus on the end play of the bearings. It wasn't huge, but I could feel a minor movement when flexing a blade toward, then away from the tower. After waiting through some good early fall winds, we (my son & I) finally got a day where the weather worked. We pulled the blades and inspected the (accessible) outer bearing cone and race. I packed the bearing with grease and re-torqued, following Timken's instructions for a target of .001"-.005".
Done with this step, the noise was noticeably better, but not gone. There was one other thing I learned though... The last couple of times I had tried to grease the bearings it seemed to take a lot of force and it was questionable how much went where intended. I had thought that the chamber was full and, if the grease cap were full, perhaps it was just hard to push by the seal. What I found, in fact, was the cap was empty. Next I tried my BIG grease gun, with lots of force this time. It was plugged solid. I'd brought a mini-torch up with me, but couldn't bring myself to put an open flame on it given the limited access. And, what if it caught. I don't own a grease ram.
You can see in the photos where I'd removed the straight, stock zerk and installed an angled fitting when we built. I then added an access hole just large enough for the grease coupling.
It's at about 10:00 in this photo:
This allowed me to grease it, but there really was no access to remove the fitting from the hub casting; not without disassembly.
Then I looked at a spare fitting that I had, and noticed that it was not a single piece, but rater two-pieces with the ball section taper threaded into the angled body of the fitting.
A 1/4"-drive deep-well cleared the access hole and I was able to remove it. I ran a small wire through the orifice in the casting wall and out came a fair amount of dry, opaque grease residue. After reinstalling the new zerk I could now freely pump life into the thing. It made a HUGE difference on removing the noise, and we're back to at least the normal noise(s). Fooosh, fooosh, buzzz.
I small win that the zerk was made as it was - and I wish I could say that I planned this - but I think we'll take pure luck this time. ~ks
