Installing pole for Turbine

Zakarume
Zakarume Solar Expert Posts: 143 ✭✭
This might be a good way or might not. Could i get a 4x4 or 6x6 pressure treated board 8 ft long. Dig hole 3 feet down. Drop board in and cement in place. Have 5ft of above ground and install several clamps in place to hold a 21ft pole and small wind turbine in place
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Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    With any useful engineering answer, you need some "real numbers" to start with... For example, how much thrust from wind will you expect on the turbine/blades?

    Next, the kind of soil does matter--But in general, I would not expect a fence post type installation (some concrete at the bottom of a three foot hole) to be near good enough for anything more than a a temporary anemometer installation..

    I would suggest reading this link:

    http://www.otherpower.com/otherpower_wind_towers.html

    If you are going to use pipe--You will need guy wires properly sized, positioned, installed, and anchored.

    There are so many ways things can go wrong with towers and wind turbines--Either get a professionally designed/mfg. tower or do lots of reading. And make sure the turbine is no where near anyone or anything that can be damaged if the turbine or tower fail mechanically. And remember wood rots/fails after a few years of exposure to water/elements/bugs.

    We just had another balconey collapse in the SF Bay Area with 6 college students killed and another 1/2 dozen seriously injured--Mainly a poorly designed and built balcony 5 stories up and dry rot from poor flashing on a ~9 year old building. Don't mess with structural design and take short cuts. The costs of failure may be too high.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Zakarume
    Zakarume Solar Expert Posts: 143 ✭✭
    Well i am trying to get it at least 20 ft up in air. Cant go higher due to location. It is only a 500 watt turbine. weighs about 40 lbs. The pipe i am using is alot thicker and stronger than a fence post. And it will be permanent.

    I have 2 ideas.

    1. 3 ft hole. drop 21 ft pole in and concrete it. 18 ft in air when done
    2. 3 ft hole. drop 4x4 or 6x6 wood pole in (pressure treated for weather). Concrete that in. And put 21 ft pole next to the wood pole and use clamps (6 min) to hold in place. 21 ft in air when done
    1460 Watts Solar @24v. 675 AH Battery Bank using 12 6v Trojan T-105. 1 Midnite Classic 150. 1500 Watt 24v Samlex Pure Sine Inverter
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Just a flag pole:

    http://www.poletech.com/PoleMountingMethods.aspx

    Would look for a 24-30 inch or larger diameter concrete filled footing.

    Could you skip the whole idea of using wood and put a pipe/receptacle in your concrete hole like they do with a flag pole?

    And replacing a flag with a wind turbine, I certainly would be rounding up for the foundation requirements for a stand alone tower.

    Also, the flag pole foundation says to have the hole bell shaped with the large diameter at the top... From what little I know, the wide part of the bell should be at the bottom of the hole.

    From this thread:

    http://forum.solar-electric.com/forum/solar-electric-power-wind-power-balance-of-system/wind-power-generation/3398-my-tower-went-down

    fetch?id=320291

    Failed that the top of the mast:

    fetch?id=320292

    Or this thread:

    http://forum.solar-electric.com/forum/solar-electric-power-wind-power-balance-of-system/wind-power-generation/17932-best-high-wind-turbine

    Fold.jpg

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    BB. wrote: »
    ....
    We just had another balconey collapse in the SF Bay Area with 6 college students killed and another 1/2 dozen seriously injured--Mainly a poorly designed and built balcony 5 stories up and dry rot from poor flashing on a ~9 year old building. Don't mess with structural design and take short cuts. The costs of failure may be too high. -Bill

    I think the balcony was OK, it was jamming +12 rowdy people onto a balcony expected to hold 5 maybe 6. I don't see how 12 folks got out onto it, it was so small.

    But don't underestimate the power of wind. And pressure treated lumber has very low strength, it's been pierced and perforated and injected.

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  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    The photographs showed dry rot (the beams did not split but had powdery breaks, signs of water damage on beams and back into the wall, and should not 2x12 be doubled up if cantilevered?)... And the load of the kids on the balcony only marginally (if that) exceed the design ratng of the balcony.

    It appears to be poor flashing and probably not very inspectable (bottom side of balcony was pretty much fully covered). Can argue what should be the design specs for a ~32 sqft balcony and 60 PSF design load vs ~14 adults on balcony

    http://www.sfgate.com/bayarea/articl...of-6331841.php.
    Attachment not found.


    Anyway--Just warning against using a wooden post (pressure treated or not) for supporting a wind turbine 21 feet in the air.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Zakarume wrote: »
    Well i am trying to get it at least 20 ft up in air. Cant go higher due to location.
    What about your location causes the 20 foot limit? Anything that is physically in the way would interfere with air flow to the turbine, even if the obstruction is 20 feet or more away.
    SMA SB 3000, old BP panels.
  • Terrang
    Terrang Registered Users Posts: 12
    Also one thing you need to think about if it applies to you..... Frost! when the snow begins to melt and ground starts to unfreeze, the ground will shift. If your pole isnt deep enough the frost will push it right out of the ground.
    It doesnt matter if its sitting in concrete or not.
    BB is correct, the soil is a big factor. i wouldnt recommend using concrete, unless you are pounding piers about 10ft to 20ft in the ground. But this gets very expensive for such a small turbine that may or may not work.

    If you have no worries about frost, i would put your pole at least 5-8 ft in the ground and pack it tight with gravel. Its a lot of work but the pole will be much more secure.
    You could add concrete at the but its not needed. The gravel will hold it just as good as long as it's packed tight.

    You also need to make sure you can access the turbine every year to check it over and fix things that are broken.
    Make sure you have good anchors supporting the tower and proper size cables otherwise the cables will snap and well everything falls.
  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    mike95490 wrote: »

    I think the balcony was OK, it was jamming +12 rowdy people onto a balcony expected to hold 5 maybe 6. I don't see how 12 folks got out onto it, it was so small.

    But don't underestimate the power of wind. And pressure treated lumber has very low strength, it's been pierced and perforated and injected.

    Nope Mike, the design live load rating in pounds per foot was more than enough to handle even the number of rowdy people that could fit on it.
    Photos clearly show that all of the possibly 2x6 or 2x8 beams cantilievered out from the main structure were dry rotted through their entire cross section in the area close to the building.
    Structurally sound lumber does not fail the way the picture shows.
    Clearly a case of water leaking from incorrect flashing. That was apparently not inspected thoroughly enough and may have been changed from the approved plans.
    The company that built the complex has paid out a multi-milliion dollar settlement on another set of buildings for shoddy construction, but apparently without injury. I believe that the details of that settlement are sealed.
    In this case I think that criminal charges may result.

    PS: I suspect that much of the remaining structural strength before the collapse came from the plywood decking that may have resisted the dry rot better.
    SMA SB 3000, old BP panels.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Just an update... It has been pretty much agreed (at least in the news) that this was dry rot. And a combination of poor or failed water barrier (probably during installation) and the fact that the bottom of the balcony was completely skinned over without (that I could see).

    The skinning over prevented any visual inspection and also prevented the wood from drying out too.

    So far, it is difficult to say if there will be any criminal prosecution... One government attorney seemed to already take a pass on the criminal case. Whether somebody else will--Don't know.

    And lastly--It is possible the balcony was designed for 100 lbs per sqft by the original engineer (vs 60 lbpsf per code). Which would have been pretty close to suffecient for even the number of people on the balcony the night of the collapse.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset