Step 4: Construct the blades

The blades are 2" x 6" pine, cut at 10 degrees on a table saw, and sanded into a rough airfoil. Not perfect, but close enough.

More can be found at

http://tech.groups.yahoo.com/group/axialflux/

http://www.green-trust.org

http://youtube.com/watch?v=o9EEHFKEckM
 
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TheStudio7 says: Nov 18, 2012. 10:23 PM
This is one awesome instructable. THANK YOU.
greenbuilder34 says: Sep 11, 2012. 7:22 PM
Hi

Your windmill looks very neat.

noobie questions:

1. Approximately how much are the 24 magnets these days?
2. What brand of resin/hardener did you use?

Cheers.
Josh
sspence (author) in reply to greenbuilder34Sep 12, 2012. 3:58 AM
Magnets run about $500 or so, and the resin we picked up at the auto parts store.
Blunt_Zephyr says: Jan 29, 2012. 3:39 AM
I've found http://www.otherpower.com/ a decent-resource on "off-grid living".

Bob174 says: Jul 9, 2009. 10:07 AM
I could not find any discussion on connecting the coils for 3 phase power output, and for connecting the rectifying diodes (how many are needed?). I could not find any information on actual performance (watts at say 10 mph wind speed,
sspence (author) in reply to Bob174Jul 9, 2009. 6:50 PM
there are 9 coils, 3 phases of 3 in series. every third coil is connected in series. the diode bridge is a 3 phase bridge, just like a car alternator. read hugh piggots book, or dan fink's.
zihanjj in reply to sspenceMar 5, 2010. 3:04 AM
 will it be simple to use a Car Alternator, but ofcourse an additional power should goto the Field coils of the Alternator, but it reduce the weight of the Generator and give's you more control. Also a cut-off if the wind speed is way too high. 
sspence (author) in reply to zihanjjMar 5, 2010. 3:06 PM
 Car alternators make lousy wind turbines and are not, and should not be used. Not just the field coil issue, like you mentioned, but also rpm range is all wrong.
thirtyfivefox in reply to sspenceJul 13, 2011. 9:04 PM
Unless you live in an area that generates 250+ mph winds steadily and use REALLY short blades ;-)
pfred2 in reply to thirtyfivefoxJul 27, 2011. 9:17 PM
or a gear box.
sspence (author) in reply to pfred2Jul 28, 2011. 1:05 PM
gear boxes are inefficient.
J-Ri in reply to pfred2Jan 22, 2012. 2:46 PM
There is a difference between energy efficiency and time/money efficiency. Turning gears robs power (due to friction) which, in low wind conditions, is better put to charging the battery bank. If it takes and extra week to build everything yourself, it's going to generate the same power when all is said and done.
J-Ri in reply to pfred2Jan 24, 2012. 12:05 AM
There are a number of factors to consider. While you are correct that huge blades would allow you to gear it up and spin an alternator faster, there are other things to consider. First, you need to mount the turbine higher. A larger tower is therefore needed, which means much more material and possible renting/hiring a crane or other lifting equipment. Second, in high wind, how are you going to stop those blades from over-spinning and ripping off? Third, when all is said and done, you have a much, much higher cost machine. One could likely build several smaller turbines with higher total output for the cost of one that could safely work as you suggest. Fourth, maintenance. Aside from greasing the bearings, I doubt the author's design requires any. What about all the moving parts and wear parts that would be needed for your idea? I know they are implemented in the multi-million dollar commercial sized ones, but you can't compare those to something like this.
sspence (author) in reply to pfred2Jan 22, 2012. 6:57 PM
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sspence (author) in reply to pfred2Jan 23, 2012. 6:06 AM
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sspence (author) in reply to pfred2Jan 23, 2012. 10:42 AM
(removed by author or community request)
dairyfarmer777 says: Jul 14, 2011. 9:47 PM
Do you have any better images of the blades besides the first one?
sspence (author) in reply to dairyfarmer777Jul 15, 2011. 6:57 PM
aistech says: Feb 27, 2011. 9:51 AM
hello im new to wind power could i build a 3 phase generator like the ones all over the net rectifiy it to dc power then put it through an inverter to tie into my house power to lower my usage

thanks
sspence (author) in reply to aistechFeb 27, 2011. 10:21 AM
Yes. You will need a battery bank, and a battery/grid tie inverter, like the Outback.
reoozeit in reply to sspenceApr 25, 2011. 4:56 AM
I agree whole-heartedly about needing the grid tie inverter! PLEASE people- by all means generate some electricity for yourself. But PLEASE either keep that power isolated from the rest of the power in your house , or get a grid tie inverter and be careful about all of your connections and use! In case you did not notice, the author stated that their house is OFF-GRID! They have a stand-alone system charging batteries and powering loads all-excusive of utility power. Remember that besides any bad things (Many are possible) that could happen if you do not connect harmoniously with your utility power, if there is a power outage, you could KILL a worker who is trying to fix the problem! You MUST make sure your power does not go out on those power lines!!! The inverters that are factory- made for tying your self- gen power into your panel (and the utility grid) are REQUIRED on loss of utility power to disconnect your system from the grid for this very reason. They also make sure that the power all matches- the cycles are in-phase with each other, frequency, etc. This keeps you alive and your house from being destroyed. Don't be afraid of generating your own power, be afraid of what happens with mis-use of that power. It can be very destructive if you try to cut the wrong corners! Also, don't fall into the trap of thinking DC power is safe because you have batteries in everything and it doesn't hurt you to change them. It is just as or more dangerous as AC when you are generating it and/or using car batteries and the like!
thirtyfivefox in reply to reoozeitJul 13, 2011. 9:00 PM
And in line with this thought, it also is a solid mention that much of the electricity that comes out of the wall is relative noise free and stays pretty stable (especially if you are living in some of the better supplied areas of modern countries) But not all of your high tech devices are going to be super happy about the new power being generated from hand made turbines. Those devices that are more susceptible to noisy power (aka those that are typically converting ac to dc using cheaply made power supplies) are going to suffer just as greatly from power sags as they would from power surges. Your electronics don't just care about how much voltage/wattage/amperage you can supply but also how clean(noiseless) that power is as well. Battery banks like the one sspence described can help alleviate the power issues on the users side but will still reak havoc on the batteries themselves (how much depending of course on the robustness of the system being used). AWESOME 'IBLE SSPENCE! I'm hoping that you wouldn't mind collaborating with me in the future as I am looking at taking myself off the grid as much as possible when I finally leave active service for a civilian life and can finally settle down in the country somewhere.
sspence (author) in reply to thirtyfivefoxJul 14, 2011. 3:29 AM
Be happy to work with you.
PresidentAnybody says: Apr 19, 2009. 1:14 AM
carbon fiber would probably be best type made as air foil, probably super expensive unless you knew how to do it yourself.
thirtyfivefox in reply to PresidentAnybodyJul 13, 2011. 8:51 PM
carbon fiber is hella expensive due to a nearly decade long global shortage... not to mention extremely difficult to work with in comparison to just good old plain spun silica fiberglass.. a couple of layers of chopped mat in between two layers of regular ol' 4 and 4 would do the trick... and he could probably get away with using the same resin he is pouring over the magnets and coils... still pricey...
sspence (author) in reply to thirtyfivefoxJul 14, 2011. 3:28 AM
a 2" x 6" is sufficient for us.
Swishercutter in reply to PresidentAnybodyJun 1, 2011. 6:32 PM
I have a friend who does (used to do?) fiberglass, carbon fiber and aluminum for custom aircraft cowlings and he claimed for most things fiberglass was close enough and its easier to work with...just needs a framework for support, make it hollow.
phillip1966 says: Jan 17, 2009. 5:28 PM
how do you make the blade hub?
sspence (author) in reply to phillip1966Jan 18, 2009. 10:58 AM
We had the triangular plates cut for us. It's simple 1/4" steel with holes drilled for the 3 blades. Will be uploading that info soon.
lwilliamson in reply to sspenceApr 16, 2011. 5:15 PM

sspence (author) in reply to lwilliamsonApr 16, 2011. 6:10 PM
um, hi?
truesprocket says: Dec 3, 2010. 5:51 AM
well done, theres a few things I don't quite get about the coils & theres connection but you've explained it fairly well, you'll need more schooling to be able to explain it to every body, lol . I have a 40 pound 12volt DC motor can I use it for a gen motor, it looks like a small golfcart motor, should I spin the shaft I see if I get power from the leads?
Picture 013.jpg
jj.inc in reply to truesprocketFeb 4, 2011. 8:10 PM
If it is permanent magnet yes, if not your probably out of luck. If it has any pull on metal that should give you an idea, or just see if it sparks when you spin it.
greedpower says: Jan 14, 2011. 8:54 AM
Could you please tell me why you would not recommend using or making PVC blades? Thanks.
sspence (author) in reply to greedpowerJan 14, 2011. 3:28 PM
They don't hold up. PVC degrades in sunlight and a 8' blade would flex too much and snap.
kaleemullaj says: May 15, 2010. 1:28 AM
goooooooood sutpindo fantastical fabulous..................
but how do u store the current...........?
or how2 use da current.........?
sspence (author) in reply to kaleemullajMay 16, 2010. 11:32 AM
 power is stored in batteries, and converted to 120vac with an inverter.
mahesh.ganpate says: Apr 24, 2010. 10:56 AM
hi .. nice  u r project can u tell me  25 kw  5.6 mtr blade balancing  mathod ..

Regads
 mahesh

sspence (author) in reply to mahesh.ganpateApr 24, 2010. 5:49 PM
 with our blades, we spin them by hand, and the heavy one stops on the bottom, so we add weight to one of the others, and keep doing that until there's no pattern to where it stops.
vordnorf says: Apr 8, 2010. 4:53 AM
 You power your home entirely with renewables and they all power a series of batteries which act as your store. However, batteries generally degrade over time. What sort of batteries do you use and how long is there lifespan?
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