time for repairs

[clockmanFRA]

I do love this forum, and the the folk that actually do.

Thanks bigrockcandymountains, yes thats what i am getting with the wood blades, Note to self, must get the blades all out of the same tree.

Thanks kitestrings for your friend 'Niels' observations.

Thanks sparweb, good to here your conclusions.

Yes sparweb, mbouwer's concept certainly has merit and can be done when still in the carving finishing stage of each blade before assembly.

Its that blasted moisture/rain water that no matter how hard i try, i just can not keep out of the wood blades.

Okay another matter that will need consideration is rotational Noise.

My Fibergalss blades on my No 2 and No 3 wind turbine make very little to no noise.

 After servicing my No 1 with the cedar blades very little noise.

However its soon heard on my No 1 that when the paint cracks or a little paint is lost on a wood blade. Then you get a deep whooshing with a high tone on top of that.

So weights at the tip will need some serious thought and testing.

The threaded stainless steel plate that is bent as the leading edge, and set flush into the leading edge, sounds like a good start for me. Just have to work out how far from the tip they can go for a safe attachment as all my wood blades tips finish at 7mm thick.

I will have to do some areo dynamics on the tips of the test screws to listen and here thier rotation noise.   

When i do the tip ends arrangement i will post on Feildlines as i go.

Photo below shows my 8mm thick blade tips on my fiberglass blades, getting foam filled with a small injection rod that i withdrawal from the blade as the raw chemical mix goes in.      Note,  a very messy process,  I leave that hole open so that any rain, moisture water can get out of the blade. Its not always successful at getting all the moisture out!

[clockmanFRA]

Kitestrings,

My apologies for hijacking your thread.

[kitestrings]

No worries...rather I've enjoyed the discussion.

I wonder if you could use some sort of desiccant material, or wick - perhaps in your next set?  I'm recalling years ago when I was doing architectural plans, we did a few of these site-laid tile projects.  An example might be a shower where there's a sloped floor to a drain, and tiled walls.  They often introduced this wick material (a cord) that was, IIRC, intended to wick moisture from between the tile and an impermeable substrate.  I think they also do this with brick veneer, where moisture can form or condense behind the material.

Of course a desiccant would have to be recharged, but silica gel is good for ~10-12 mos.  Perhaps a tube near the blade end that you periodically force in new, dry material, and extract old, moisture laden material.

[kitestrings]

Finally got the right combination of whether and work-force to put this thing back in the air.  We got a blessing in the form of unusually warm, calm early November weather.  The task was fairly clear... put this:



...up there:


With the help of my long-time climbing partner, Neilho, my wife and my 10-yo (who anchored on the 4-wheeler) it all came together:


Add a stator (don't try this at home):


and a view to make you forget Covid for a day or two:



We're up and running again.  More to re-cap what we changed later, but a serious test the last couple of days with good winds.  Pretty happy to have it up for the winter when we need it most.  ~ks

[SparWeb]

It sure looks awesome up there.

[bigrockcandymountain]

Woo Ya!!  Congratulations on getting this back up in time for winter.  Climbing that tower is very cool.  Your ambition on this project blows my mind.  Hopefully your balance works out and you get some production in the next few days. 

[DamonHD]

All looks magnificent: turbine, lansdcape, tower, everything!

I'd be more than a little queasy up that high!

Rgds

Damon

[Bruce S]

It sure looks awesome up there.

I whole heartily agree! That View sure looks great!

Bruce S

[gsw999]

Great view, looks like a very well made wind turbine you have there !!! many kudos

[kitestrings]

Thanks for the encouragement.

The latest efforts on this project expanded quite a bit, but in some ways allowed us to make some tweaks that hopefully improve things for the long haul.  Summarizing the main objectives and alterations, we:

1) Removed all of the magnets
2) Refinished the rotor plates
3) Epoxy primed all magnet surfaces
4) Replaced magnets, this time with the retaining rings spaced off the rotor plates
5) Replaced the polycarbonate stator rings with .25" x 2.3125 G10/FR4 (slightly thicker & wider)
6) Inserted spacer stops and shrink-wrap expansion sleeves on all stator connections
7) Replaced bearings
Refinished blades, taking trailing section to a sharper edge & rounding-off a portion of the leading edge closest the hub
9) Adding leading edge tape
10) After initial static balance.  Balanced rotor as an assembly with the magnet rotors
11) Shimmed for proper tracking

The blade changes are noticeable.  The blades are much quieter, and we eliminated a rather annoying whistle that occurred at a one speed.  The balance is improved.

We still have some work on vibration dampening when the controller is clipping the sine wave, that has not changed.  Something left to tinker with -

Production has been good, but intentionally restrained as I gain comfort with things.  So far, so good though.  Saturday I started it mid-morning and shut it down when I went to bed, and we logged just under 7 kWh, and we've had peak output of 3.7 kW.

Working out this gin pole was a win, and overall testing the concept of a removable stator was positive, though next time I might do 3-pieces instead of twelve.

A few more pics:

[MattM]

I'd be tempted to throw a camera up there with that excellent view.

That is nice!

[MagnetJuice]

overall testing the concept of a removable stator was positive, though next time I might do 3-pieces instead of twelve.

Doing the stator in 3 pieces would greatly simplify the construction. Especially the assembling up on the tower.

It would be good to see a rough sketch of a design for a 3-piece stator, that way some of us could start dreaming about building something similar.

Nice work KS.

Ed

[bigrockcandymountain]

That was a big overhaul and a lot of work.  Congratulations on the production.  3.7kw peak is a crazy amount of power.  That will keep the toaster toasting. 

I see you put leading edge tape on.  I did mine last spring, and in this last snow storm we had freezing rain, wet snow etc
  It used to ice up instantly in those conditions but with the tape on it didn't even a bit. 

I think your blades are finished way smoother than mine, so maybe the benefit won't be as obvious, but a great thing to have on anyway. 

What is the thickness of your trailing edge now?  Are we talking like knife edge?   I really like the idea of quieter.  I get a whistle too.

Did the bearings show wear? Or was it just conveneint to do while it was apart?

[kitestrings]

Doing the stator in 3 pieces would greatly simplify the construction. Especially the assembling up on the tower.

Being able to take the stator out, in our case, meant the entire head assembly - the tower mount, yaw assembly, tail-boom, hinge and vane - could all stay on the tower.  This significantly reduced the weight of our heaviest lift (to about ~#135).

I've been giving some thought to a future design, where the stator is similarly cast, but only in two or three sections.  I was envisioning a design where the stator sectors engaged one another, were pulled together and locked with a cam-lock (like closing and locking a window sash), and where the same motion made the electrical connections between the sections.  Probably far-fetched, but if your going to dream, right?

bigrock, if you look at the latest photo where the blades are on the paint rack you can see the different (from pics earlier in the post).  Nearest the tips, I tried to take them to a near knife-edge, but more generally narrowed the last three or four stations.  Nearest the hub, there is a point where the theoretical profile has to transition to the square-edge root section where the blades are fastened to the plate.  Here, I tried to just continue the rounded,  leading-edge a bit closer to the root.

[Bruce S]

Please tell us in that last pic the ends have some sort of clear finish on them.

Bruce S

[kitestrings]

Good question, but yes.  It must be just the way the light is hitting the ends.  They have the same primer, paint; actually multiple coats there.

[kitestrings]

An unexpected turn -

On Friday we had moderate, variable winds with shifting direction.  When I got home I immediately noticed a new, unwanted noise (any noise, right).  It has always had a low 'growl' at about 200-400 watts where the controllers are clipping the waveform.  Past this point it mostly goes away.  What I noticed was that this noise was much louder and longer than it had been - like a cow 'bellering'.

I shut it down and over the weekend checked things out.  What I found was there was end-play on the rotor; not huge but I could feel it and I could see it.  Unfortunately, this meant removing the blades.  Fortunately, we had pretty favorable weather Sunday morning, and I was able to do it all on the tower (without lower the blades).




I had torqued the bearing as I had in the past, and as recommended by Timken... torque to 50'# while rotating, back off one full turn, then re-torque to 10'# and back off one to two flats.  It was definitely looser than I had left it.  I suspect one of two possibilities: 1) the front bearing may not have been fully seated against the spindle shoulder, or 2) the weight of the magnet rotors allowed the assembly to shift slightly forward when I backed off the 'one full turn' on assembly.  Seems like I would have noticed that -

The goods news is it all went smoothly.  I took up a considerable amount of play... I dunno, ~pushing half a turn.  It made a huge difference.  Back to normal/acceptable noise levels (or better).  The blades are actually much quieter, so I'm happy with that.  Note to self: next time, keep the blade roots clear of the hub, and add a nose-cone (originally this was the plan)so as to access the bearing with the blades in place.  A fair amount of work, but just happy to have caught it early; with favorably weather.

[SparWeb]

Indeed that would have been hard to tolerate hearing in a storm, while waiting to fix it.
Can't think of a similar experience with hub bearings coming loose like that.  I'm afraid the first thing that comes to mind is a piece of debris, on which the bearings were hung up rather than seated against the shoulder, until rolling dislodged something.

[bigrockcandymountain]

I have had that happen with trailer axle bearings and such. Usually it is a cup not fully pressed into the bore.  They get a little cocked.  I usually torque pretty tight (more that 50 ft lbs) and spin and bang on the tire with a rubber hammer.  Then back off and torque properly.   

Good job making it right. 

[GreenTeam]

WOW! Just wow
I am vertigo out just from pictures of what you are doing.
I admire your courage.
BTW, I am native also, Talhtan First Nation

[kitestrings]

Nice to have this thing back up and running again.  We're at the point where it's dark at 4:30 in the afternoon, so even a good solar day isn't what it was just a month or so ago.  Today we did 3.6 kWh with the solar array and 6.4 kWh with the turbine.  My 10-yo has been putting up holiday lights - modest by comparison - it's nice to have power.

GrnTm, did someone else comment on being native?  I may have missed it.  My grandmother, father's side, was Abenaki.  (I'm not sure if that helps with heights though ;>]

[kitestrings]

Today was pretty either snowing, or over-cast, or both.  I cleared off the solar panels, which involves an extension ladder and telescoping pole on a "Sno-pro".  This is routine in the winter, but today the the peak array output was maybe 80 watts.

Solar for the day:


It was, however, quite windy.  Steady.  I started the turbine this morning about 7:30.  By 8:30 tonight we'd logged nearly 10 kWh (the second controller has maybe .5-1 kWh):


Running smooth, quieter; gaining confidence in things.

[DamonHD]

I merely have fog (and pigeons which have learnt to sit on the panels) today...

Rgds

Damon

[Mary B]

Ice fog here, everything is getting fat with frost...

[SparWeb]

Zzzzzz...
Says it all.

[bigrockcandymountain]

How do you like the the outback charge controller? I have thought about one if i add solar to the shop build. 

Almost 1000w average is awesome.  Im glad you got it back working. 

[kitestrings]

The Outback controller (MX60 IIRC) was our original PV controller, and more recently we bought the two, Midnite Solar, Classic 250s for the wind turbine.  I've never had any problems with the OB, or the OB inverter we use as our daily driver.  If I were to add one today, I'd probably go with MS, only because their customer service has been first-rate.

The turbine is working well.  I've spent quite a bit of time paring down the noise issues.  The blades were the obvious improvement, and that lies mostly with taking down the trailing edge to a sharper finish.  The alternator was more of a challenge.  Quite a useful discussion here:
https://www.fieldlines.com/index.php/topic,148450.msg1030962.html#msg1030962

One of the things I revisited was the sort of "play-thru" suggestion that boB suggested.  After focusing on where & when it occurred, it seemed to be building on a resonant frequency of the structure.  I adjusted the power curve (I'm up to 8 now) to reduce loading at these steps, and the results where significant.  Probably more to do, but along the lines of the 80/20 rule I'd say.

Lastly, if I take a critical review of where we've been, there are of course things I might have done differently.  By far one of the best wins though, was adding power furling.  To be able to shut the thing down, in any sort of storm, from the house...in about 30-secs. has really been wonderful.  And, knowing it can and will do that when I'm gone, under the right conditions, is also comforting.

[GreenTeam]

HOw many feet high is your tower?

[kitestrings]

It's ~90'.  We had a 100' Rohn 25G with a lighter (12' dia) machine for many years. When we built this one we went to a heavier Rohn 45G, but dropped the height just a bit.

It's windy here though.  We're around 1,400 feet in elevation (low by western standards), but at the crest of this ridge.  We are on a comparatively lower ridge that runs parallel to two higher ridgelines: the Lowell's and Sheffield Heights, both of which have commercial-scale wind turbines.

[kitestrings]

Finally...some decent winds again.  We had a coupe weeks with mostly overcast weather, mild temps and little wind, but today we're back in form:

[kitestrings]

We logged 11.2 kWh for the day from 07:30 AM to 10:30 PM when I shut it down and went to bed.  The peak output was about 3.5 kW at 109V.  The FET temps didn't go over 49 degC; safe, comfortable numbers: