6 inch quick-vawt
By feral air, Section Diaries Posted on Tue Oct 02, 2007 at 07:59:04 PM MST
pics

<BR><img src="http://www.otherpower.com/images/scimages/8639/6qv_a.jpg" width=80%><BR><BR><img src="http://www.otherpower.com/images/scimages/8639/6qv_d.jpg" width=80%><BR> Let me say up front that the copper pipes and pipe fittings were handy and are on loan from my boss - he's got lots of scrap gathered up from over the years - it's not soldered together and will get replaced with pvc. I didn't have enough 3/4" pvc fittings laying around is all. I think when I switch to pvc for the frame I'll bring the pole down the center line of the vawt. I'll probably use a galvanized conduit pipe for the pole and will want to add guy ropes to it with stakes on the ends....think camp charger. The OD on the rollerblade bearings is the same as the ID of 3/4" fittings which is handy. For some reason I'm using two sets of bearings on each end as you can probably see in the second picture but I doubt I need to. I'll remove a set from each end later and see how that works out. You should be able to see the flat "L" corner braces turned into a "U" bracket. I don't like that there's only one bolt on each end holding the pvc on but these 1inch "L"s were the best I could find. Having just one hole makes it easy to align tthough - so if you plan to make one and you can find better Ls (or "U"s, let me know!) with 2 holes then start with one bolt, get it aligned, and then drill the pvc and set the other bolt. The air gap is 1 and 1/4 inch on this one. On the 4" version it was 1". I don't care so much about efficiency though so maybe more/less gap would be better. You can easily change the gap though by changing how you mount the blades and adding extra nuts. I'm not sure if top/bottom plates add efficiency to this or not, I've just never tried adding 'em. Some kind of bottom plate will be needed to protect the bottom bearings from rain (which you'd need for the alt anyway) so if you're a symmetrical kind of person then a top plate would be required too. I think this part is pretty much in the bag at this point. There's not much to it and all these parts together shouldn't cost too much. Garage sale rollerblades, some pipe and pipe fittings, 4 Ls and some bolts. The only thing left is the alt, really. I guess that's the tricky part though so I'm all ears as far as that goes.

6 inch quick-vawt | 15 comments (15 topical)

Re: 6 inch quick-vawt (3.00 / 0) (#1) by feral air on Tue Oct 02, 2007 at 02:00:02 PM MST

That's what I get for not hitting preview I guess...

Re: 6 inch quick-vawt (3.00 / 0) (#15) by DanB on Wed Oct 03, 2007 at 08:29:54 PM MST

Neat project!  Thank you for sharing it and especially for putting up nice pics.  Be fun if you get some kind of generator working well with it/see what happens. [ Parent ]

Re: 6 inch quick-vawt (3.00 / 0) (#2) by DamonHD on Tue Oct 02, 2007 at 02:39:36 PM MST

Please let us know what Watts you can extract from it at what sort of rpms in what wind... Rgds Damon

Re: 6 inch quick-vawt (3.00 / 0) (#3) by feral air on Tue Oct 02, 2007 at 03:58:07 PM MST

I'm pretty well stumped on the alt so it could be a good long while before I know any of that stuff... What gauge wire should I go with? 2 in hand? How many turns? 9 coils in series, maybe? Ahhh! I'm at a total loss on the whole thing. I'm basically clueless on the electrical side. [ Parent ]

Re: 6 inch quick-vawt (3.00 / 0) (#8) by DamonHD on Wed Oct 03, 2007 at 02:18:51 AM MST

Don't look at me.  You're all clued up by comparison! Rgds Damon [ Parent ]

Re: 6 inch quick-vawt (3.00 / 0) (#4) by RP on Tue Oct 02, 2007 at 06:14:08 PM MST

Dude!  You shoulda flushed some clear water down that pipe before you cut it.  ;-) Seriously, that's a nice rig.  I wonder if a stepper motor would be suitable for an alternator.

Re: 6 inch quick-vawt (3.00 / 0) (#5) by feral air on Tue Oct 02, 2007 at 08:35:18 PM MST

I thought the dirt and cob webs (believe it or not it was never used) added contrast and made it easy to see what was what...yeah, that's it. I'll clean 'em tomorrow. :-) Thanks! That's a good idea - if I could find a surplus stepper motor to go with it that wasn't too expensive that'd be perfect. Time to go hunting I guess. [ Parent ]

Re: 6 inch quick-vawt (3.00 / 0) (#6) by CmeBREW on Tue Oct 02, 2007 at 09:08:18 PM MST

Looks interesting. Good work. Heres one on youtube that looks very similar and about the same size. They can really spin. http://www.youtube.com/watch?v=lUpXokjLF1o I was thinking of doing one out of the 6" pvc drain pipe like yours, but make it 8 feet high!  There just don't seem to be enough torque with only 2 feet. You may not even need a top bearing. I just made a prototype that is 39" high (18"diam) ,and it is alittle off balance in lower winds, but when the stronger winds hit it, it staightens up perfectly and spins really nice! I didn't expect that! I even saw it survive what had to be a 70mph+ wind during a terrible thunderstorm last week. It seriously looked like a hurricane on TV! -That was amazing and mega surprising. The one I am almost done with now is 5 feet high with no bearing at the top. (2 feet diam)   You might think about making it 8 feet high and direct drive an ametek motor. Keep up the good work. Can't wait to see that PB-Vawt up in the air go!

Re: 6 inch quick-vawt (3.00 / 0) (#7) by feral air on Wed Oct 03, 2007 at 12:16:11 AM MST

That vid isn't even close to the same thing. :p Good find though. 6"x8ft...that should do it! You're really on the ball there. I guess for vawts, like for extreme sports, the saying should be "go big or go home". ;-) Taller/bigger would be better for a permanent windmill but I really want something portable. I was thinking of building in a spot for a 9.6v RC-car battery pack (swapable of course) and building in led lights. Portable self-charging lamps for when we go camping. With that in mind, I don't want them to be too big to pick up and take into the bushes when nature calls. I'm not sure about bottom-only bearings. Especially as you go higher, it just looks flimsy. That's just how I feel about it though - I'm a symmetrically-minded person so top and bottom bearings are basically a must just on those grounds. I can see how it would tend to straighten up when it gets going though - it's like spinning a top when you think about it. You should get pics of your builds, it sounds like you're doin' all kinds of interesting stuff! [ Parent ]

Re: 6 inch quick-vawt (3.00 / 0) (#9) by electrondady1 on Wed Oct 03, 2007 at 06:00:33 AM MST

i suggest you replace the bottom elbow with a t type fitting then run a longer central shaft right through it. attach a steel disk to the central shaft use that as a platform for your magnets. [ Parent ]

Re: 6 inch quick-vawt (3.00 / 0) (#12) by CmeBREW on Wed Oct 03, 2007 at 05:38:47 PM MST

Hopefully tomorrow I will try my best to show the progress and pics of the 'Squirrel cage' Vawts I have been working on. They got me very excited from the initial tests. The small one (18"diam. x 39" high) usually goes 200-600rpm and with some decent torque.(depending on the winds)  In fact, it is hooked to a treadmill motor and it is ALWAYS 'shorted', and it turns the same rpm as if it was freespinning. During that 70mph hurricane like wind last week, it must of been going close to 1000rpm and it was as straight and steady as an arrow! So it looks very promising. Tomorrow I will put the bigger vawt (2feet diam. x 5 feet high) up for testing.  They are impressive because the wind flows thru and 'swirls' fast in the MIDDLE of the vawt 'cylinder shape' thereby EMPOWERING ALL the 24 blades forward for maximum TORQUE per revolution!  At the same time, the air resistance (drag) is very low on the opposite side since the blades are so close together.  I really think I like this one. It will certainly do WATTS. [ Parent ]

Re: 6 inch quick-vawt (3.00 / 0) (#13) by feral air on Wed Oct 03, 2007 at 06:08:05 PM MST

Oh, I think I've seen those designs. Are they the ones where you put the blades around in a circle and angle 'em in slightly? There's a youtube vid that shows one that they pit against a Savonius...the squirrel cage wins, handily. I would love to see a good break down of one of those. I mean, part of the reason I went this way is because of how easy they are but if it's not much harder to build a squirrel cage then I'm in. Especially if you've got a design that's actually producing something from a treadmill motor! Treadmill motors aren't exactly cheap but they're certainly available.. Oh yes, I'm intrigued. [ Parent ]

Re: 6 inch quick-vawt (3.00 / 0) (#10) by wooferhound on Wed Oct 03, 2007 at 06:17:27 AM MST

You really should put a Top & Bottom plate on there. They help to contain the air and keeps the air from spilling off of the ends of the pipe. They also have the small effect of straightening the air making less turbulence.   W o o f -={(

Re: 6 inch quick-vawt (3.00 / 0) (#11) by ghurd on Wed Oct 03, 2007 at 06:43:47 AM MST

I have a feeling that will explode in big wind. Might add a length of all-thread through all 4 layers about the middle?  Like the 'U' bracket bolt, but a lot longer.  Not sure it'll help, but don't think it'll hurt. About any 99 cent stepper motor (old printer in the basement?) will get it charging AAs or lighting LEDs. G-

Re: 6 inch quick-vawt (3.00 / 0) (#14) by feral air on Wed Oct 03, 2007 at 08:24:46 PM MST

Woof, I kind of want the air spilling out the top though... Each blade is only held on by 1 bolt on each end. This one isn't intended for really high winds...20mph gusts max. The blade area is pretty small too so that should help keep it from exploding. Besides that, it'll only ever be about 5ft off the ground and will be within arms reach when it's set up. If the blades were any taller (and the set up more permanent) I would definitely use heavier-duty brackets, more bolts and at least one bracket/bolt of some sort in the middle. Top and bottom plates would likely improve efficiency (if they don't add too much weight) but I'm willing to trade on this one...I do need a bottom plate of some kind though to keep water out of the bearings. ghurd, see above. :-)

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