Tower Ready to Raise

[SparWeb]

Hello everyone,

I've spent the last couple of weeks assembling the tower for my windmill (and I have the mosquito bites to prove it!)

I opted for the 3" pipe, tilt-up type, 45 feet tall.  The lowest section is 3" pipe, the next section is 2.5" pipe, and the stub is 2".  I made the yawing generator head with 2.5" pipe that I will install once I have the hang if this tower thingy.  It is much like the design that is featured on the "how-to" part of this site.  Dan hasn't asked me to pay any him royalties yet.

This isn't actually the first time I've raised it - I snuck it up into the air on Sunday for the first time (no kids or dogs around).  The weather was quiet when I started, and I set some cable lengths and tensions, but then an electrical storm rolled in, and I decided to put it back down - real quick!

Here you can see the tower on the ground.  Not enough pixels for all the guy lines to be visible.  The gin pole is fairly long, but I had 20' of 3" pipe sitting around...  The upshot is that the tower is very easy to raise: 350 pounds to get it off the ground (measured with a scale), and the load gets smaller, the higher it gets.  Also due to the long gin pole length, the weight of the gin balances the tower.  I got off the tractor when the tower still had 15 degrees to go, and I pushed it the rest of the way up, by pushing the gin down by hand.  It moved gradually and smoothly.  Everything came to a stop at the apex without any abrupt wobbling - and presto!

This is where I've made a few errors - nothing catastrophic.  I can't drill out one bolt to full size because I can't get the drill between the base supports.  How stupid!  Also stupid is forgetting to cut a hole in the pipe to let the power cable come out!  It's all fixable, but so much easier if I'd done it in the shop!  

The middle joint is pretty busy.  The anchor is 22' from the base, and the first 3" pipe is 21' long, so a lot of cable ends come together in the same spot.  The guy wires are small here - they just stabilize the middle of the "noodle".  There is also the 3/8" lift cable connected to the gin pole.  The tower looks like a soggy noodle if I don't pull it up with a middle lift cable.

Here's the top set of guy wire attachments.  These cables do the real work, so they're 1/4".  I opted for eye bolts to make attachments, so there are a lot of multi-purpose fasteners.  The eye bolts attach the pipe segments, absorb the bending loads, and connect the guy wire reactions.  It sounds like a lot, but there's still lots of margin.

If you've been reading my other postings, you'll see I live in a lightning alley, and I'm going to install lightning protection before I get too far.  Some schemes I've read about sound very complicated.  I would rather make the tower pipe as well grounded as possible and divert the current from the power wires as early as possible.  But these tower joints may prevent that from working...

Steven Fahey

[pepa]

nice work Steven, you could drill a small hole in the anchor bracket and use a drill bit extention to drill that last hole. it looks like you will have enough clearence at the outside of the anchor bolt. pepa.

[kenputer]

If you could get your hands on a angle drill you would be able to drill that hole with out any problem.

  I see you did get some of the power pole guy anchors.  nice job!

Ken

[RP]

The last picture shows a threaded chain-link at the end of the lift line.  I'd suggest using some thread-lock on that since it will be up there vibrating in the wind for a long time before you use that lift line to lower it down again.

Nice set up and nice write up!

[SparWeb]

Using those threaded quick links is so-ooo convenient, but I have carefully resisted using them as much as possible.  Some loc-tite is called for.

[SparWeb]

Now why didn't I think of that when I had that hole-saw out?!?  Good thinking, pepa!

RP, I paid dearly for the small quantity of anchors that I bought (supplier prefers to deal with volume).  But they are SOLID in the ground.

[BruceDownunder]

Hi,,

 I'm not one for being negative,.Please understand my thoughts are only for your safety .

I have a 55 foot tower ,like yours.

  I would ,if I were you, increase the size of your fittings ,turnbuckles,Shackles,Wire grips,  and standing wire to 3/8 inch.

Do away with that chain-link thingo,there ok for boy scouts camping ,,not this  sort of lifting gear-unless you get one quite a bit larger.

The ground anchors,,are they concreted in with a "dead-man" anchor  ? oe are they those screw-in thingo's ?

Bruce dosen't like them screw-in thingo's ,.

Like your metalwork and ginpole arrangement,seems you have the balance correct.

hope I'm not too sad with my remarks.

Look at my tower,turnbuckles,anchors,wire terminations, winch  Etc  in my album on the IRC photo -Album site.

Bruce

[TomW]

Folks;

You can find Bruces' IRC Gallery over here:

http://www.anotherpower.com/gallery/brucedownunder

In case you were not clairvoyant enough to guess where we hide it.

Cheers.

TomW

[SparWeb]

Bruce,

All comments are welcome.  The chain links don't make me comfortable, either, and I promise to eliminate them soon.  This tower will be raised and lowered several times this summer as I make improvements / repairs / etc.  I will have many opportunities to inspect and replace the hardware.

As for the anchors, the manufacturer's data sheet specified a 5000 pound load in my soil category.

The tower has been analyzed by by hand, and by FEA.  All components have a safety factor > 4.

If you still believe it's not enough, just say so.

I'll be looking at your photos in a minute to see where you're coming from.

Did you (or an engineer) analyze your tower's loads?

P.S.  I studied a Southwest wind turbine tower when I started designing mine.  The drawings are probably still available on the website, if you want to look.  Looking at the details in the design, a lot of it made sense.  I also realized that several parts of the tower were over-designed.  5" pipe is not necessary for a 30' tower.  By reducing the pipe size to 3", the weight of the tower can be cut in half, and all of the loads associated with raising it drop in proportion.

Thanks for your comments.

[spinningmagnets]

Thanks for posting the detailed description and the pics. Even if every part is taken from pre-existing web-data, a picture is truly worth a thousand words, and the more projects that are posted the better! I have not made a wind-gen yet but you have been very inspiring, and this web-site is the best! -Ron

[jmk]

 You can spread those thimbles by twisting them sideways. Then you can delete the chain link all together. I think your ok anyway. Your turbine isn't that big to put that much load on it. I think your fine with those screw in anchors as long as you have good ground. I wouldn't use them on a big tower, with a big mill on top though. Just my thoughts.