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grolly

Regular Member

Joined: 19/05/2007
Location: Australia
Posts: 62

Posted: 12:21pm 22 Apr 2008

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Hi all, thought I would try my hand at building a VWT, so far so good, 8 ft trailer axle ,16 ft x4in bore casing, 2 x 44 gal oil drums, and an idea that has been ratteling around in my head for a while now. Dug a deep hole and put the axle in it,

then spent the rest of the day filling it with cement

welded the pipe to the rim that came with the axle, and stood it up to see how true ot rotated, and as you can see ran out of light.half oil drums in background.

will continue when I get more time.
grolly

I have bought the farm...now I AM powering it...

oztules

Guru

Joined: 26/07/2007
Location: Australia
Posts: 1686

Posted: 11:00pm 25 Apr 2008

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Looking forward to the rest of this story Grolly.

You don't seem to have a windbreak for a considerable distance, so this would seem to be a very good wind site for a Vawt on the ground.

Keep the camera handy....oztules

Village idiot...or... just another hack out of his depth

grolly

Regular Member

Joined: 19/05/2007
Location: Australia
Posts: 62

Posted: 05:52am 26 Apr 2008

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Hi Oztules, you are right, at the moment I have a house in the middle of what was a field of oats,

I have planted some trees, and they are all of half a mt tall, a way to go yet.
This is what happened to my 500 watt wind gen a few weeks ago,

It`s back up now with slightly shorter blades

still puts out good numbers, at the moment it is putting 4 to 12 amps into two 24 volt fork batteries (745 amphr each)as a dump,
`cos it`s blowing a gale here today, and FINALLY some rain, almost forgot what it was.

Grolly

I have bought the farm...now I AM powering it...

grolly

Regular Member

Joined: 19/05/2007
Location: Australia
Posts: 62

Posted: 05:56am 26 Apr 2008

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sorry that should read 475 amp hr batteries

, its a bugger being old

I have bought the farm...now I AM powering it...

Gill

Senior Member

Joined: 11/11/2006
Location: Australia
Posts: 669

Posted: 09:00am 26 Apr 2008

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Grolly,
I'm very interested in the failure of those blades. It looks like metal fatigue to me, but to happen to all three blades like that???? I'm building a mill using 6 of those Chinese aluminium blades modified with a twist, so want to know if there is anything you can add to the story as to what may have caused it and do you have any recommendations to stop the same thing happening to mine?

This appears to be a down side to these blades of uniform size, no strength at the root. I'm thinking now to glass fill the two larger cavities in the extrusion to at least half the blade length. What do you think?

With a back yard like that the family would play a lot of cricket. Ay.

was working fine... til the smoke got out.
Cheers Gill _Cairns, FNQ

grolly

Regular Member

Joined: 19/05/2007
Location: Australia
Posts: 62

Posted: 11:54am 26 Apr 2008

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(((It is very windy here, already have broken all 3 blades off the wind gen, don`t know how hard it was blowing (back sliding glass door visibly bending, house rocking) but it was putting out 35 volt 16 amp full furl,, at 3.30 am all blades broke off at the hub.
more on this not very good wind gen later. )))

Hi gill, top bit from another post of mine, as you can see it was really blowing, the thing was swinging around so violently that I think the blades hit the tail or started to flutter, when on full furl it sounded like a turbo prop plane warming up.

Two of the breaks could have been cut with a profile cutter ,they are so identical, and the other blade was bent with a bit of yellow paint on it off the tail and a small dent in it, which makes me think a glancing blow.

This was while I had it at 6 mt high, I have now taken one section out of the pole, and is now a bit over 4 mt, still pushes the needles off the scale and trips the overload on the regulator.

I have had this wind gen to pieces about 5 or 6 times, the red plastic tips came off one at a time in the first blow, makeing it vibrate, and chewing out the rear bearing housing, had a lot of trouble getting it shimed, and balanced, finally used a coffee tin to shim it and a collar to hold the shims in, it is running smooth at the moment, for how long I dont know....the tail bearing is also choped out too, so before I got it running smooth, the tail assembly would bounce up and down, shaking the whole unit.
so as you can see the blades have had a lot of rough treatment,I would suggest a lot of atention to the balancing, and seeing that my blades flex about 4 to 5 inches at the tips, make sure that they cannot hit the tail.

While it was in pieces, I also thought of filling the holes with something to give them more strength, seeing I am off grid, I didn`t have the time to do it tho. This wind gen , when it is working, keeps the 24 volt pressure pump batteries up to float most of the time, have not used the 240volt charger on them since I first put it up, but I have set fire to the big green resistor in the regulator box, too much power for it I supose, still works, but trips out sooner, no time or money to replace/ fix it at the moment.

No kids to play cricket, but feel free to come over for a game anytime if you are in the area.

Grolly

I have bought the farm...now I AM powering it...

grolly

Regular Member

Joined: 19/05/2007
Location: Australia
Posts: 62

Posted: 11:59am 26 Apr 2008

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PS, Just out of intrest sake, the new wind generators like this one now have reinforced fiber glass blades supplied with it, and 4 guy points not 3 like mine, could be they are fixing a falt with them?
Grolly

I have bought the farm...now I AM powering it...

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