Author Topic: An 8' diameter wind turbine experiment  (Read 10853 times)

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DanB

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An 8' diameter wind turbine experiment
« on: April 02, 2005, 02:57:09 PM »





I've also been working on some parts for a sort of 'kit' - or at least parts to make assembly easy and a nicer looking machine hopefully.  Depending on the magnets we use, and how we wind the stator I think this 'platform' is good for 8 - 11' machines.  A freind I met over all this wind turbine stuff (Art Randolf) is making pretty neat fiberglass reinforced nylon blades and a variety of hub options that he'd like to sell.  I've been wanting to build a machine to test these on now for over year... finally got around to it.  This will be an 8' diameter wind turbine.  Pictured above is the 'magnet rotor' - it has 12 of those wedge shaped magnets.  As usual, the rotor is mounted to a trailer hub, the bolt pattern is 4 holes on a 4" diameter circle... pretty standard.  The magnets are segments of a ring such that 24 of them will form a ring 12" OD and 8" ID, they are 1/2" thick.  They seem to perform almost exactly the same as the 2" diameter X 1/2" thick disks I've used on past machines (so with the same stator we could use either magnet and expect very similar results).  They cost about the same as well.  With 2 disks loaded with these magnets, we seem to have a pretty reasonable 11' machine (10' machines will stall a bit) - some folks up here have put 12' props on them.  Im shooting to run a single rotor here and hoping it will match up nicely with this 8' blade set.


... yes, thats right, a single rotor - with no laminates or anything on the back side.  It's not 'proper' - and not the best use of magnets, but on the other hand, if it works out, it's very easy to put together, very easy to adjust.  The extra we might spend in magnets is offset by the savings in time/money involved with a 2nd rotor.  The magnet rotor lays flat on the trailer hub, the stator sits right behind it.






We figured.. since the stator will be very visible from one side.. we should try to make it look cool.  Here's our first ever 'designer tie die stator'!  Its got 9 coils wired in star, the coils are wound with 55 windings of #13 wire.  Cutin speed with the single rotor is 180 rpm.  The resistance may be too high - she might overheat, time will tell.  If that is the case, Ill rebuild the stator with fewer windings/heavier wire and probably go to running with a blank steel rotor on one side of it.






Here is the alternator assembled.  I could've put the magnet rotor either on the front or back of the stator.  On the front there doesnt seem to be any noticable attraction to the stator brackets (if there were I'd turn it around).  I like the look of it better on the front... it might cool slightly better if it were on the back.  I think it probably doesnt matter either way.





Here are Art Randolfs blades all painted up green.  The hub he provides makes this an 8' machine, and the hub fits the bolt pattern perfectly.  This setup is also probably quite suitable for use on Hugh Piggotts 8' axial flux machine.  My only concern about these blades is their flexibility... we'll need some clearance between them and the tower.  They may also flutter and make a bit more noise than the wooden blades I'm used to.  But - in their favor, they are very tough - you cannot break them.  I have no doubt they would survive striking the tower at very high speed.  They are also fairly inexpensive.





These are the steel hub pieces I normally put on both sides of the wooden blades.  With Art's blades its not necessary - the hub is very strong, but it looks nice with these on both sides.





Here we have Art's hub sandwiched between the two steel pieces and bolted to the alternator.  The plastic hub (fiberglass reinforced nylon) come in two halves, and the blades slip into holes.  It goes together very easily.





Here I've stuck the blades into the hub.  You can see the twist/taper in Art's blades.   They look very workable.





There it is almost finished up!  We'll probably complete this machine on Monday, then we'll finish DanF's tower at his house and test it there for a while.  My bet is it'll work OK if the stator can take the heat!

« Last Edit: April 02, 2005, 02:57:09 PM by (unknown) »
If I ever figure out what's in the box then maybe I can think outside of it.

drdongle

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Re: An 8' diameter wind turbine experiment
« Reply #1 on: April 02, 2005, 08:30:25 AM »
Keep us informed on those blades, what choices will be available and the cost, I know that I would be very interised.
« Last Edit: April 02, 2005, 08:30:25 AM by drdongle »

DanB

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Re: An 8' diameter wind turbine experiment
« Reply #2 on: April 02, 2005, 08:33:32 AM »
You can call Art about these blades if you're interested in them.

His numbers:

870-449-4000 at the shop  8AM-4PM

    home phone # is 870-449-6225


I'm not positive, but I think the whole setup is around $100, perhaps slightly more.

« Last Edit: April 02, 2005, 08:33:32 AM by DanB »
If I ever figure out what's in the box then maybe I can think outside of it.

electrondady1

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Re: An 8' diameter wind turbine experiment
« Reply #3 on: April 02, 2005, 08:36:40 AM »
dan, please , try not to have any model a  fords in the backgrounds of your photos as i find it very distracting.
« Last Edit: April 02, 2005, 08:36:40 AM by electrondady1 »

drdongle

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Re: An 8' diameter wind turbine experiment
« Reply #4 on: April 02, 2005, 08:39:53 AM »
Great thanks, does he have E mail?
« Last Edit: April 02, 2005, 08:39:53 AM by drdongle »

DanB

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Re: An 8' diameter wind turbine experiment
« Reply #5 on: April 02, 2005, 08:48:22 AM »
Yes, sorry I forgot that.

elsieart@ozarkmountains.com
« Last Edit: April 02, 2005, 08:48:22 AM by DanB »
If I ever figure out what's in the box then maybe I can think outside of it.

drdongle

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Re: An 8' diameter wind turbine experiment
« Reply #6 on: April 02, 2005, 08:52:43 AM »
Most exelent dude, thanks!!
« Last Edit: April 02, 2005, 08:52:43 AM by drdongle »

picmacmillan

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Re: An 8' diameter wind turbine experiment
« Reply #7 on: April 02, 2005, 09:18:30 AM »
hi dan, pretty cool project...it is very simlar to my setup with the plates and trailer axles, although i use dual rotor...i am not too fussy for the tie die colors though :)..i am an old fashioned school colors guy...but very nice,always

         :) ..pickster
« Last Edit: April 02, 2005, 09:18:30 AM by picmacmillan »

windstuffnow

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Re: An 8' diameter wind turbine experiment
« Reply #8 on: April 02, 2005, 10:45:43 AM »
  Pretty cool Dan...


    Let's see bell bottom jeans, tie die shirts, open field concerts, hair down to my .... those were the days... although the late 60's and early 70's are a bit fuzzy I do remember some of the fun we had!  


Keep up the great work, anxious to see some data on it.


Windstuff Ed

« Last Edit: April 02, 2005, 10:45:43 AM by windstuffnow »

veewee77

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Re: An 8' diameter wind turbine experiment
« Reply #9 on: April 02, 2005, 08:02:43 PM »
Does he make a 10' set, too?


Doug

« Last Edit: April 02, 2005, 08:02:43 PM by veewee77 »

scoraigwind

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Re: An 8' diameter wind turbine experiment
« Reply #10 on: April 02, 2005, 09:37:08 PM »
Thanks for that, Dan


Another neat project, beautifully presented.


I can hardly believe that you don't experience some drag from the magnets passing those stator mounts so close by though!  They look to me like an eddy current nightmare.  Don't you feel any drag at all?  Maybe I made the single rotor stuff much too difficult for myself but I really thought I had to avoid metalwork that close to the magnets.

« Last Edit: April 02, 2005, 09:37:08 PM by scoraigwind »
Hugh Piggott scoraigwind.co.uk

DanB

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Re: An 8' diameter wind turbine experiment
« Reply #11 on: April 03, 2005, 05:18:57 AM »
Thankyou for the comment Hugh, it's nice to have someone inspire me to double check this stuff.


It seems to turn quite freely, and there is no noticable cogging at all.  I'd have expected some cogging, with 3 stator brackets like that and 12 magnets.  It's not noticable when turning it by hand though.  The magnets are about 2.5" away from the stator bracket, so the field is not too strong.  But I did just check it with a Gauss meter and find that at the bracket there is still a fairly strong field (about 250 Gauss) - so there must be some drag which I'm not noticing.


With that in mind, I think I'll put the rotor on the back side of the stator, facing foward.  Then I'm quite sure it'll be a none-issue.

« Last Edit: April 03, 2005, 05:18:57 AM by DanB »
If I ever figure out what's in the box then maybe I can think outside of it.

Flux

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Re: An 8' diameter wind turbine experiment
« Reply #12 on: April 03, 2005, 07:06:18 AM »
If you can't feel drag and it spins freely it is probably of no consequence. With a complete disc it might be of some concern but with 3 spokes it should be minimal at 2.5".  I don't think it is worth complicating the mechanics by turning things round.


Flux

« Last Edit: April 03, 2005, 07:06:18 AM by Flux »

DanB

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Re: An 8' diameter wind turbine experiment
« Reply #13 on: April 03, 2005, 07:19:46 AM »
it does seem to turn quite freely as it is....


What do you think about the stator Flux?  The resistance is fairly high I think compared to other 8' designs (like Hughs plans) - but... these blades seem like they'll want to run fast and I think Hughs leans a bit towards stalling (I think its perhaps a bit on the powerful side for an 8' prop).  I doubt this will stall... and the cutin speed is nice, but I wonder if it'll overheat!  I will have it furl early.

« Last Edit: April 03, 2005, 07:19:46 AM by DanB »
If I ever figure out what's in the box then maybe I can think outside of it.

Flux

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Re: An 8' diameter wind turbine experiment
« Reply #14 on: April 03, 2005, 08:02:29 AM »
Dan I've not a lot to go on for the resistance but if the stator is 1/2" thick it looks as though you could be up near 0.5 ohm. If so that brings you down to 50% efficiency around 300W and you will be running quite hot at 450W.


I personally think it would be a much better machine all round with a second rotor plate with no magnets and fewer turns of heavier wire. There would be negligible increase in cost or difficulty of manufacture and it would be far better to move the losses to thin connecting cables rather than have the losses in the stator.


If those blades are fast I would aim for cut in for initial tests at 180 rpm but be prepared to increase the rotor gap to bring it up to at least 200 rpm. I have a feeling that you will do better overall with a bit higher cut in rather than going for added resistance alone to reduce stall.


If this turns out to be the case I would wind future stators for the higher cut in with the smaller gap.


Flux

« Last Edit: April 03, 2005, 08:02:29 AM by Flux »

tecker

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Re: An 8' diameter wind turbine experiment
« Reply #15 on: April 03, 2005, 06:47:24 PM »


 Looks like a stainless cap nut there

« Last Edit: April 03, 2005, 06:47:24 PM by tecker »

nothing to lose

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Re: An 8' diameter wind turbine experiment
« Reply #16 on: April 03, 2005, 08:06:21 PM »
How much do you want for that truck!


Looks like a great job as always, wish you the best of luck with the new design. I really hope those blades work good for you. One of the reasons I really hope so is that I just called Art and I am driving over to get a set tommorrow myself :)


Please take note if you call him, 10:00pm is a bit late. I don't keep track of time to well since I don't keep normall hours myself and seldom sleep normall times. I didn't realize it was already 10pm, I normally try not to call people I don't know that late at night.


 I think I bothered him a bit, but he was very nice about it, sounds like a nice friendly guy. He told me he used to make 44' blades for Jacobs I think it was. Retired awhile back and now started making blades like these again. He said he's had a set up several years now and no problems.


Since he is only 80 miles from me I am driving over tommorrow (Monday) and buying a set myself, he said I can see his mill flying. And we'll probably shoot the bull abit too.

 I'll know more when I get back of course, but I beleave he said he has other plates also that can be used for varius types of mounts. Probably blanks set up for his hubs and then you drill the blanks out for your mounts perhaps. I'll see when I get there.


 I am not sure what I will mount this new 8' set on though. But they are close to me, cheap enough at $99, I had no plans for Monday this week, and I want to build something new and larger for a mill anyway.


I still have that Dayton 180Vdc 11-6amps 2hp motor sitting in my living room :)

 I wonder if this 8' set will drive that motor? I had figured my little set of barrel blades would be too small and never tried it yet.


 I still have about 20 of those round Neos I bought long ago from you guys and the wire too. I think the neos were 2" dia and 3/16" thick maybe or something close. The roll of wire was what was suggested for the single brake rotor mill, perhaps no. 14 or 16 ?

 Any suggestions on using the above for a trialer axle mill like your building now? If I take down one of my motor conversions I can get another 4 magnets for 24 total, maybe do a daul rotor with those? Think those 2" thinner neos will work ok for one of these mills? Any suggestions on the coil windings?


 Also just curious, when you guys wind coils, how many coils does a roll of wire normally yield? I know variables like wire size and number of turns effect that alot. But in general, does one mill eat a full spool or do you get a couple mills from one spool? Like this one you just wound up for example? How many coils would that spool do?


Looking forward to tommorrow's "Another Monday, another Pizza Party" posting and see what you do this week :)

« Last Edit: April 03, 2005, 08:06:21 PM by nothing to lose »

aogden

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Re: An 8' diameter wind turbine experiment
« Reply #17 on: June 13, 2005, 08:59:06 PM »
So how did those Art Randolf blades perform afterall? I was thinking of investing in a set.  My average wind seed is low (class 1) so there may not be adaquet torque in  5-10 MPH to make a few watts? What are your thoughts?

Regards,

Adrian
« Last Edit: June 13, 2005, 08:59:06 PM by aogden »

funkeytut42211

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Re: An 8' diameter wind turbine experiment
« Reply #18 on: July 24, 2005, 07:18:51 AM »
Im curious now that this experment has been up and running a while how has it turned out so far as output and how are the blades from art doing? Has it all ment your expectations.
« Last Edit: July 24, 2005, 07:18:51 AM by funkeytut42211 »