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Dan Lenox
2nd June 2008, 15:57
All,

(5/29) About a month ago a buddy of mine and I attempted to raise the blades onto the wind turbine at the top of my 70' freestanding tower. A number of technical glitches prohibited us from accomplishing this task. Believe me after that day I certainly had both 'tower envy' for those with tilting towers, and secretly wished that I had gone solar.

While I really like the aesthetics of the free standing tower, it provides me with challenges that those who have tilting towers never have.

Recently I completely rewired my tower (making it far better than original), put up a long Kellem wire grip onto my cables, made my davit crane better, added eye bolts on top to clip onto, replaced my C40 with a Tristar TS60, completed all wiring, among many other tasks.

Let's just say that I have become quite proficient at climbing my tower, and I understand a lot more now about inverter back-end systems than when started.

Up till recently I had to wait till the weekends to perform any work on the tower/turbine, but problems of weather/wind/logistics I have not been able to get the blades and tail up onto the turbine. It is always windy here and that along with the non-tilting tower have provided many obstacles.

Last Thursday the weather report finally was kind to me and we had next to perfect weather with only 3-4mph winds. So I took the opportunity to try to get things operational here.

First up were my blades and tail sections onto the turbine. The stator was shorted so that the rotors could be turned but would inhibit the blades from rotating. With the stator shorted you can turn the rotors, it does not turn easily but this gave me the ability to align the rotor to the holes on the hub.

Here is a picture with me threading the nuts onto the threaded rod that holds the blades onto the turbine. I used lock washers, lock tite, and double nutted each stud:
482
Once the blades were on the brake actuator was engaged to positively keep the blades from rotating, and the guide rope was removed.

Next up was the tail this was a little more difficult as the lift point was a little bit off on the tail. The lift point should be slightly off center and away from the tail vane so that it can be put onto the yaw bearing easily, my lift point was on the side towards the tail vane making it slightly difficult to maneuver. But eventually I was able to man-handle it and get it onto the pivot point.

The next picture shows that the lift point was too far out and was also a reach for the winch as well:
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Once the crane was lowered the gentle wind rotated the turbine to point into the wind, I was cautious and made sure that I did not get in the way of it swinging. The crane worked *very* well and I am quite happy with how it performed.

Next comes Murphy's law again - the telescoping tower stub. When we connected the winch and attempted to lift the stub it would not move. As it started to lift I could see resistance from the lower mounting plate.

Last fall prior to having the crane lift the tower into position the stub was checked out to ensure that it could rotate in the mounting collars, if it can rotate, the it can be telescoped. I suspect that since the tower was lifted by the top mounting plate that the alignment of the collars got 'tweaked' a bit. I put a long bar through the pin hole and tried to rotate the stub, but it would not move.

Hind site being what it is I believe that I should have made the lower mounting plate with the collar separated - instead of welding them together. And then using some L's on the collar and bolted them through the top of the plate would have been the best solution. The mounting bolt holes could be slotted to allow the collar to be shifted and easier to get/keep aligned. Experience really does make a difference in these small design and construction details. While I really like the aesthetics of the free standing tower, it provides me with challenges that those who have tilting towers never have.

At this point I had been on the tower easily 4 hrs and was getting tired so decided to call it a day.

I believe that what I need to do is loosen up the bolts that hold the mounting plate to the tower and align the collars. A job for another day!

Here are a couple of pictures of the tower with the completed turbine mounted:
484485486

(6/2) OK the weather gods were with me again, perfect weather with just a hint of a wind. Murphy is still around - but I beat him today - and got the telescoping stub raised! In climbing the tower early this morning I realized that the lower mounting plate could not be removed for modification since 1/2 the lattice braces are located on the inside of the tower structure. So instead I loosened the bolts that held the lower mounting plate in position and when I got the winch mounted into place and gave it a try, this time it worked!

In my working with the design that I have I found one thing that repeatedly came back around - forgetting to design in allowances for things like hooks. It has been a close call on a couple of occasions (sometimes by inches) and I barely squeaked by with enough room or height.

But it all finally came together for me today and I got the wind turbine raised and into operating position.

Here are some of the pictures that I took from various angles:
487488489490
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In the next week or so I can finally get the turbine operational and get some electricity generated and data accumulated.

Once I can get my transfer switch installed between my electric meter and my main panel I can push any 'extra' power generated back into the grid.

Recently I took pictures from the top and stiched them into two panoramic 180 degree images, they can be seen at:
http://www.briery.com/wind_turbine/images/panoramic_view_sm.jpg
http://www.briery.com/wind_turbine/images/panoramic_view2_sm.jpg

Dan Lenox

Martin Gray
2nd June 2008, 18:56
Nice project Dan.
I've been watching your progress for a while. Good to see it's almost complete.
I can relate to your tower "challenges", having a 100 foot freestanding one myself.:eek: It's really not so comfortable working that far off the ground.
Nice pics also.
Martin.

Rob Beckers
3rd June 2008, 06:41
Absolutely beautiful wind turbine Dan!
I wish you many happy wind generated kilo-Watt-hours!

Your setup is grid-tied if I remember right? Do you have any regulations over there for towers and wind turbines? Permits, inspections and that good stuff. If so, I'm interested to hear how that went.

I'm happy to see you have an anti-fall steel line running up your tower. I really think that's the way to go for any climable tower, with the clip-on slider hooked up to your harness. Makes climbing much, much safer.

Great setup Dan!

-RoB-

Dan Lenox
3rd June 2008, 08:12
Rob,

I am pretty rural out here in WV (the main reason that I moved out here 9 yrs ago). About as flexible as you can get, no permits nor inspections for any type of building - basically nothing!

Yes I am grid tied. The only inspection will be from the power company when I hook up my transfer switch. They had that one requirement about a positive disconnect. The only 'test' that they said that they would do is to ensure that the inverter disconnects when the grid drops out.

I would not climb my tower without the anti-fall line! I also use two 18" long Elk River lanyards with lobster claw hooks, they work great for fast clipping and un-clipping. I'm pretty paranoid so almost always I'm double and even triple clipped in at all times.

Dan

Rob Beckers
11th October 2008, 07:45
Dan, it's been a while since the last post regarding your turbine. By now it has hopefully been operational for some time, and I'm curious how the turbine is working out. Any comments?

-RoB-

Dan Lenox
11th October 2008, 09:50
Rob,

As you know for the last couple of months I have been busy writing software for monitoring/logging data from my turbine and Xantrex XW inverter. I now have accumulated about 3 weeks of actual run-time data. I have been working with Xantrex and they have been an invaluable help in working out some issues. If interested more information can be gotten at http://www.briery.com/wind_turbine/build_log7.html

It has all been a great learning experience! However along the way I realized that I had measurement problems, from bad analog current meter, irregularities in measuring Hz (rpm), as well as anemometer issues (averaging).

One by one I have been addressing them, but still working on making my own digital anemometer. So I still question wind speed.

Also along the way I realized that my wind turbine has a stall issue in that the generator overpowers the blades. To help I have installed a massive .6ohm, 6kw power resistor, this has helped the turbine in medium winds. I still have a bit of a stall issue, but I am also in a pretty good wind area, so better a bit stalled - than a bit loose - as the following numbers will show...

So I know that my turbine is under-performing, but I'm willing to live with it as it appears to have good high-wind survivability. Over the last couple of months we have has 48mph winds two times and once 58mph. Seems that when the wind really blows here that it is a very gusty wind, with huge bursts of high energy, a number of times I have seen output of 5-6kw!

With all explainations, here are some numbers:


Wind
Speed RPM Watts
------ --- ------
6 105 250
10 127 400
14 145 900
18 160 1400
-- -- --
34 240 4400
38 255 6400


You will notice one section not present, it is a gray area as with my anemometer averaging and wind gusting I can't get any good readings.

The top end is pretty apparent! At some point large gusts of wind have caused the turbine to begin to 'break away'!!

So far I have been present when these events have occurred and have manually shorted out my line resistor, that appears to get the turbine back under control and slow it down in quick order.

This is one reason that with the software that I am designing that I will have the ability to have the computer automatically switch out the line resistor for me.

I should add that I got the 17lb, 24" long, .62ohm 6kw power resistor from a guy named Nando, if anyone is interested in purchasing one (less than $50) contact him at nando37@tx.rr.com

Once I finish up the interface to the anemometer I should be able to get more accurate instanttaneous wind speed measurements. I am working with a PicAxe chip, and will have a wireless ghz transmission that should be easily read for almost a mile...

Hope this helps!

Dan Lenox

Dan Lenox
12th October 2008, 09:03
Rob,

I have been told by Flux (at http://www.fieldlines.com/) that with a wind starting at about 14mph, I am starting to stall, and by 18mph stalled as a brick.

I'm well aware of the stall and for now it is ok for now. I have a couple of choices one to increase the line resistor fro .6ohms to 1.0ohms. From my initial testing (and Flux's recommendation) the 1.0ohm significantly improved performance.

Or maybe next summer when I bring the turbine down for some maintenance I will increase the air gap a bit. And if possible before then replace the plywood tail with some frp to lighten it up as it only gets to partially furling.

I am grid tied but don't want to deal with high output (4-6kw), because it's typically under those conditions that the grid goes down then I would be forced to dump that massive load...

Dan

Brian Pearl
14th October 2008, 13:08
Wow, what an in-depth walkthrough! I'm recently interested in learning more about do it yourself projects like these and went through your detailed report over at http://www.briery.com/wind_turbine/build_log1.html and was amazed once again. You really got a taste for how much work is involved to take on such a project and I'd like to thank you for taking the time to share it with everyone.

Sorry for your trouble with the tower installation crew, nothing pisses me off more than underquoting contractors, but that's a completely other rant...

I went through some of your pricings and saw that it came out to around $14,000 from the prices you mentioned on your turbine build log. Does that seem about right for materials + 3rd party services?

It looks like your doing quite well now, are you happy with the project as it stands now?

Dan Lenox
14th October 2008, 13:14
Brian,

Yea that cost sounds about right.

Actually with having the contractor bail on me, in the long run it was a good thing, I was forced to learn about the back-end electronics. Plus saving myself a *bunch* of money that would have gone towards them...

Still 'tweaking' things, I will be repacing the wood on the tail with some light weight FRP. Next summer when I take it down for maintenance I will probably add some more air gap to loosen it up a bit.

So it's an ongoing project, along with the software that I am developing for monitoring/logging (and eventially control).

Dan

Brian McGowan
15th October 2008, 00:33
That is a very nice turbine. I am really liking that tower. I need to have a freestanding tower and will probably resort to a telephone pole but would feel much more comfortable climing that tower than a pole. It would be geat to also have the tower tilt but I probably won't get that without guy wires. I can only go up 40' and my maximum diameter would probably be about 8.5' so the telephone pole is doable for that. In the begining I am planing to just buy one of those 5' ones with a PMA and learn from that. It would not be too expensive and not be a really big loss if I destroyed it somehow or discovered there is really not enough wind to make it worth it. There is a guy about 3 miles from me that has an old Enertech unit up on a telephone pole. After that I would probably build my own from scratch so that's why I would want to have a pole that could take an 8.5' turbine. I figure that's the biggest I could possibly need to go here.
Once again, very nice turbine.
Brian

Dan Lenox
17th October 2008, 07:28
Good wind yesterday, able to fill in some 'gray area' in my numbers.

I'm going to have to modify the output listing from above, took measurements with the .62ohm load resistor inline:

24mph winds, 220rpm, 3000watts output

I was getting spikes of 230-250rpm with close to 4kw output during some quick bursts of wind.

By manually cutting out the load resistor, it brought things back down to 150rpm, 800 watts.

Dan