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Forum Index : Windmills : My PVC blade f&p mill is up and going

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Chris220220
Newbie

Joined: 17/02/2010
Location: Australia
Posts: 29

Posted: 09:47am 18 Jun 2010

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After a lot of set backs and a not so successfull VAWT I have a mill up and running.
That project is not yet dead. (A Lenz2)
It is a F&P setup with 3 40inch PVC blades.

I see why the experienced members suggest big blades.This critter takes some starting. I still have the differential output to two 3 phase rectifiers. I was getting up to 60v unloaded. Put the battery on it and the mill slows right down and will not run a 12v 50W globe

I found I can vary the mill by also adjusting the rear plastic plug and move the magnetic hub in and out.

I have decided little mills may spin well unloaded but try hook a load on them and I suspect they just ground to a hault.

Here is a link to the mill spinning today, a gusty day in Melbourne
http://www.flickr.com/photos/cboylen/4711513710/

A few questions if that is ok:
Do I need to trim the blades?
Should it run the globe on the end of the rectifier circuit?

All comments and suggestions are very welcomed

Regards
Chris

Chris220220
Newbie

Joined: 17/02/2010
Location: Australia
Posts: 29

Posted: 10:15am 18 Jun 2010

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Well I thought it was too good to be true.

I have just come back inside with rather sore hands but nothing broken.
I backed off the hub and this helped the mil get spinning and the globe was starting to light in the stiffening breeze.

It was going great with the globe bright and the mill going full bore. It was then I noticed the mill was starting to get a lean up. It was starting to lift and rotate upwards. I thought time to get the blades off and call it a night. As the wind eased I climbed on the stool to get the blades down, well the mill decided to depart from the water pipe upright at the same time. I looked up and caught the mill. As said a few cuts but nothing broken. Blades and me all intact

The interference fit into the water pipe looks like it will need welding in place.

I will check it out properly tomorrow in the day light.
The wind has blown up to gale levels tonight. A good test for the mill and me.

Regards
Chris

VK4AYQ
Guru

Joined: 02/12/2009
Location: Australia
Posts: 2539

Posted: 01:47pm 18 Jun 2010

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Hi Chris

Glad to hear you survived the attack of the killer turbine.
While you have got it down check the balance and the blade angle as the effect you describe is induced by blade imbalance mainly but also if the angle of attack of all the blades are not equal, If you haven't already read it, go through the blade fitting link from the front page.
Have you decogged the stator as it sounds like you have got some cogging making it hard to start, even with cogging it should start in the conditions you mention. By loosening the rotor you may also have induced some imbalance in the rotor as it is only plastic and not a real good fit on the spline.

Good luck tomorrow and wear a hard hat.

All the best

Bob

PS : A globe will work on AC or DC but when the three phases are combined through the rectifier you will have more power to drive it, but it will put more load on the mill.Edited by VK4AYQ 2010-06-19

Foolin Around

MacGyver

Guru

Joined: 12/05/2009
Location: United States
Posts: 1329

Posted: 04:36pm 18 Jun 2010

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Chris220220

Glad your injuries are minor. Don't feel like the Lone Ranger; the rest of us have sliced & diced ourselves plenty and even severely pinched fingers on mega-magnets so you're not alone!

Everything I build is small; it's my thing. That said, I can tell you the mill needs to be higher, above yard obstacles like houses, trees and the like to grab any serious wind (gale-force winds notwithstanding!).

I use a simple tower made of pipes and it might be something you could use too. It folds down in a jiffy so you can bring your genny down for repairs and whatnot whenever you want by simply pulling the bottom pin. There's a whole story on it in the "Windmills" section; the thread is called "MacGyver's Tower".

Mine is only about 15 feet high (neighbor problems) but I had the exact same thing in Florida and it was 40-feet tall; worked the same, except I had a concrete counterweight attached to the bottom of the center pole (the moveable one) to ease in raising and lowering the windmill without having to be Mr. Muscle.

. . . . . Mac

Nothing difficult is ever easy!
Perhaps better stated in the words of Morgan Freeman,
"Where there is no struggle, there is no progress!"
Copeville, Texas

Chris220220
Newbie

Joined: 17/02/2010
Location: Australia
Posts: 29

Posted: 07:50am 19 Jun 2010

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I'm lucky the mill is fully intact and so are the new blades.

The postwas on a mean lean this morning so that would not have helped the mill staying ontop the pole last night. Must have been one almighty gust that bought it all down.

I recall the halegon globe was fully alight at the peak of it so the mill was pumping at least 50Watts into it.

Is that still a bit light on for such a setup? I would be happy with pumping out 5 amps to recharge my batteries, but doesn't an F&P put out a lot more than that?

Would some timber blades work better than the pvc?
I was going to use the 1m by 180mm design I found somewhere else in the forum.

I have tried to decog it but it still "goes lumpy" when very slow. Guess I haven't rounded the plates off enough. Slow going with a hand file.

I'm looking at trying to put the larger base pipe up on the shed so I can slip the thinner tube in it and have the mill much higher. That will take a bit more engineering and a few more weekends to get set up.

All in all I was very lucky.

Regards
Chris

KarlJ

Guru

Joined: 19/05/2008
Location: Australia
Posts: 1178

Posted: 12:32pm 19 Jun 2010

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Get onto Anthony (aka Jarbar) if you're in Melb and he'll help you out by loaning you the tool to twist the poles.
Hand file is a serious waste of time, get a flap wheel for the angle grinder and cut sick (after they are twisted)

Now -what is the re-wire status -if you havent re-wired it it will be heavily loaded with 12V device connected and thus stuff all output.
Gordon's cap mod works well too.

Blade angle s crucial, with 40" the thing should go like a banchee. I found personally using one of Trev's hubs I couldnt get the angles close enough, hence a move to Phills Mill where it remains adjustable.

My twin stator mill makes 700W in 8m/s+ (thats it unfortunately) but comfortably cracks out 1.5KW/day avg.
thus the single should crack 350W no problems

can't wait till you're blowing halogens!!
Oh and be careful!

Karl

Luck favours the well prepared

dwyer
Guru

Joined: 19/09/2005
Location: Australia
Posts: 574

Posted: 01:26pm 19 Jun 2010

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Hi Karl
Did you said "My twin stator mill makes 700W in 8m/s+"
So what blades diameter and how many blades you are using to run at 8m/s as l can't get the Tev's blades start at 8m/s with single stator until 20km/h wind (load supply on ) started blowing once is running is fine. tev's blade is 2.1 i think ?

Dwyer

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