Author Topic: Cheating local zoning laws with a VAWT (Read 4469 times)

Todd a · « **on:** July 14, 2008, 11:09:59 PM »

I have been looking into local zoning laws where I live for tower restrictions. There are a few for wind turbines it turns out. The tower has to be in the back of the house, no taller than the distance to the nearest property line, and no more than a 5' diameter. Well I have a very small yard, so I will have to do a roof mount and do to the massive diameter restriction I am going to work with a VAWT.

That said I am working with 2"x1/4" arch magnets. 16 make up an 8" disk with a 4" openning in the middle. I am using 2 of these disks on 3/16" steel plates. The stator is 9-12 coils of 18g wire with 100 windings. I am using small car wheel bearings and a 3/4" shaft. I'm using 24" aluminum struts to attach the 4 4' wooden blades made from 1"x8" boards. The whole thing will sit on an 6' tower on the roof.

I am leaving it open to various options for testing... 1 or 2 magnet plates and 4 or 8 blades. I am even leaving an option for 1/2" thick magnets or larger diameter and blades (based on my testing of above combinations. I'm looking at about $400 for everything (except the thicker magnets). I'm hoping for 500w or more in the 24v 20 amp range or better. $1 a watt is not too bad. I need to make the bearing sleave, cut the steel plates, and weld them together. The rest I can do myself. I also need to get the resin and make the molds for the stator.

Wish me luck

spinningmagnets · « **Reply #1 on:** July 14, 2008, 05:53:33 PM »

Dear Todd a, I cannot have a HAWT where I'm at (so I am fascinated by VAWT's), so, "I feel your pain".

You may wish to research the issues concerning vibration and harmonic resonance (whatever that is) when attaching any spinning device to your house structure.

Even if you don't experience any damage, the hum that is fed into the house frame at higher RPM's (I'm told) can be very annoying. You may wish to incorporate some form of thick rubber isolation mount on the pole that uses the corner of your garage for strength, but cancels most of the buzz.

Disclaimer: I havent built one of these, so, Your Mileage May Vary (YMMV)

wooferhound · « **Reply #2 on:** July 14, 2008, 06:00:58 PM »

You have a great Plan, except the part about mounting it on your house. Make sure you have a Kill Switch so you can sleep at night. Plus reinforce everything so the low frequency hum/vibration doesn't loosen everything up. Plan on frequent checking to see if the vibration/hum is pulling things apart. In fact, just forget about mounting it on the roof !!

Todd a · « **Reply #3 on:** July 15, 2008, 06:44:33 PM »

I am going to balance it very carefully. I am also use very strong bearings. The generator is actually mounted in the middle so there is no torque on the bearing with the wind blows against the VAWT, just a side load that the bearing is designed to take. Now the cogging of the generator will be the big issue. I am using 16 magnets with somewhere between 9 and 12 coils in 3 or 4 phases. This will help reduce cogging I am hoping. The last thing I am doing is adding some dence foam under the pad for the tower and under the collar that the cables will mount to.

The big question I have though is would it hurt if the wire coils are bigger than the magnet and overlap more than one magnet at a time. I figure they will be fighting each other too much.

I am thinking of doing 50-60 wraps on 12 with 4 phases instead. If I use 12 coils and 3 phases I would have all 4 coils from single phase lining up with 4 magnets at the same time. This would put a lot of power at one time through a single phase. with 3/4 ratio I will have only one one coil in each phase over a magnet at the same time. Maybe I have it all wrong, but I usually see 12 magnets generators with 9 coils, so I was going to stick with the same ratio.

I am likely going to make at least 3 stator rings of different configurations as I got a 7 pound spool of 18g wire and I will have enough glass and epoxy for 3-4 stators. I am trying to keep the coils pretty flat, like around 3/8" to 1/2". I might even try 15 coils with 40 wraps and three phases just to see what it does.

I got a weather station to monitor wind speeds, but I do not have it on a tall enough pole where I have it to clear the peek of the roof. As it is I have been showing I have a lot of wind around here. Today it has been running about 8-16mph at this lower location. My VAWT will be about 10 feet higher than what I have the weather station at and clear of the roof peek.

Todd a · « **Reply #4 on:** July 17, 2008, 07:30:23 PM »

Actually I think I am going to make three stators. One will have large coils 100 wraps with 12 coils in 3 phases. I will likely do smaller windings that fit the magnets better (no overlap between the magnets). These will likely be about 50-60 wraps, but with the same 12 coils and 3 phases. I am also thinking of 15 windings and will try both 3 phases and 5 phases. These coils will be the smallest at about 40 windings.

I have almost everything to build it now except some 3/8 IS tubing to use as spacers between the magnet plates, the stator and mounting plate, and the mounting holes in the stator. I even got all the crimp conectors, the wood to make the mold for the stator, a better soddering iron, lots of extra bolts, the epoxy and glass, and the drill bits. I am ording laser cut magnet plates (only a few bucks more than getting the plates on-line). I will order those tomorrow and pick them up monday. I am hoping to make at least one set of blades and maybe one stator finished. Maybe by next weekend I will have it ready to start testing.

I have done a small VAWT (18" tall and about 8" across) and a 3 foot HAWT with pretty poor results do to too low of budgets. Too weak of magnets, poor bearings, cheap materials.... Now I am going much bigger, with about 10x the magnets strength, heavy bearings, steel plates and tubing, heavy bolts, aluminum struts...

Todd a · « **Reply #5 on:** July 20, 2008, 10:26:31 AM »

Well I got the Epoxy now and made the molds for the stator ring. I also have the bearing sleave done. I am making the blades on Wed, possibly the first stator ring today (12 coils 75 wraps each and 4 phases likely). I am getting the magnet plates laser cut (2 3/16th inch plates cut 10" diameter with a 2" hole in the middle and 8 3/8" holes on the inside and outside hub). Both plates are costing $48 for the plates and cutting. I am likely going to cute the stator mounting plate today. I also picked up the bolts and spacers needed. Once the magnet plates are in I can weld the bearing sleave onto one of the plates. I need a peice of tubing to mount the shaft to and weld the stator mounting plate to, then I can assemble the whole generator. If everything looks good then I can install the blades and add it to a temp tower and start testing. I have 4 nice bridge rectifiers and all the connectors, crimper, and wires.

Some paint would be nice too. It will be read generator with zink plated bolts, aluminum spaceers and trusses, and white blades with red tips. I need a logo and name to stencil on the blades too to make it look proffesional. Then I cross my fingers and start testing. I will try different angles on blades to get the best speed and torque. Then I add 4 more blades and test more. I will aslo make the other 2 staor rings and test those. Then I get a 1200w invertor I have been looking at and make a roof plate and cable collar and get some cables and eye-bolts.

Wish me luck. 2400 pounds of magnetic pull and about 300 feet of wire should give me some good potential. I'm am just worried I will need to use a pulley set-up to gear up the generator speed.

Todd a · « **Reply #6 on:** July 27, 2008, 12:30:22 PM »

Well I molded the stator... the mold release did not work... the wood was too porous and stupid me I did not seal it first... or line it with something (which I will not do again). It took me about 2 hours with a hammer and wood chizle to get the stator out of the mold... or remove the mold from the stator would be more accurate. Well it is still in tact. This epoxy is almost indestructable. All 4 phases of my 12 coil stator still work. The stator ring turned out 7/16" thick.

I was going to assemble the whole thing this weekend, but the place laser cutting the magnet plates had 2 people out sick so they will not be done until monday. I did set the stator ring over the magnets that ar attached to a steel plate I will use for the base of the tower and found the magnet strength was still very strong through the stator (enough to grab a apir of pliers out of my hand when I got too close). I think this thing will be pretty powerfull.

The blades are done, the stator mounting plate is done, the stator ring is done, the bridge rectifiers are wired up, the trusses are done, I have all the bolt sorted out, I have the shaft and the tower ready. I just need those magnet plates, some welding, and some paint and I will start assembling this thing.

I will start with fan testing (4 20" box fans) to test the blade angles and such, then I will move to a trailer for some speed testing at 10-20mph for ssome output test ranges. Then I will take it slowly up to 70mph and see how the thing holds together. I went with aluminum trusses, but maybe I will need steel trusses instead.

ghurd · « **Reply #7 on:** July 27, 2008, 01:13:12 PM »

"I will start with fan testing (4 20" box fans) to test the blade angles and such"

Not Good!

Far too turbulent to get anything even remotely meaningful.

I wanted to cry after a box fan test, until there was a slight breeze.

Fan test was maybe 45RPM.

Under 6MPH (below the limit of my meter) outside was too fast to see.

G-

Todd a · « **Reply #8 on:** July 27, 2008, 04:00:30 PM »

Yes I know it can be turbulant... That is why I was going with 4. I can move them back a bit and run them a lower speeds. I was also thinking of funnelling the wind down with 2 4'x4' peices of drywall I have laying around. I was looking for something I could set up and have reliable wind for testing pitch angles and the number of blades. I am trying 4 and 8 blade set-up. If the rotation is enough I might also try different stator plates with 1 and 2 magnet plates (and 4 and 8 blades) to really see what the effects are. The trailer test is for higher wind speed testing.

Maybe I am a bit ambitious, but I think the generator is capable of 1Kw or more, but I worry that the blades might not turn it the best or that I need higher RPMs and will need to add a pully and belt system to increase the RPMs of the generator. I am hoping changing the pitch can increase RPMs, but decrease torque and I can find a good spot in the middle.

The city where I work is playing with wind and solar power. They are adding 3 Swift Turbines made by Cascade Engineering (about 50 miles from me too). These are 7' multi blade HAWT (I think 5 blades). They are designed to be roof mounted and can supposadly generate 1.5KW of power each. The problem is they are spending $11,000 for each one. That is $33,000 for the wind power and it looks like the solar aray will be pretty big and likely cost about the same amount. That is way too much. I doubt that would have even close to a 25 year payoff.

Todd a · « **Reply #9 on:** August 02, 2008, 11:10:16 PM »

Well I got my laser cut magnet plates back and they look perfect. I also got some thicker tubing for the bearing collar and made up the new magnet collar. I was going to weld everything together a few days ago, but my neighbor was on vacation and has the welder I was going to use. Then he got back and informed me his dad actually had it right now and was in the middle of working on welding up a frame on a car he was restoring. It did not look like I was going to get to use his for a few weeks.... . so I order an arc welder from Sears (on sale with free shipping). It shipped Thursday, so hopefully it will be hear when I get home from work. After it is welded I will paint it and add the magnets. These delays are driving me crazy. I want to start testing it.

I'll post more pictures when I get the welder

spinningmagnets · « **Reply #10 on:** August 03, 2008, 01:11:36 PM »

You probably already know this, so I'm not trying to insult you, but...

If you are new to welding, don't think you can whip out a quick job by squinting your eyes, while you plan on getting a face shield/dark goggles later.

Also, I highly recommend you practice on some scrap. If you are already experienced at welding, I apologize for any assumptions.

Todd a · « **Reply #11 on:** August 05, 2008, 05:06:20 PM »

It has been MANY years since I welded. Yes I use a welding mask... my neighbor thinks sun glasses are fine. The sun burn he got was pretty bad. I took 3 years of metals in school and the last year was about 80% arc welding. Yes that was over 20 years ago. I do not have much in the way of scrap, so I started in a less important location (the cylindar the shaft mounts to. It took a bit to get used to the welder, but everything worked out. I got about half the welding done and it might not be as nice as I used to do it is more than functional enough. I have tomorrow off work so I should be able to finish up the rest of the welding, touch it up with my angle grinder, and get it painted. If I have time I will assemble the generator and finish the wiring.

Todd a · « **Reply #12 on:** August 07, 2008, 08:31:38 PM »

I did some clean-up with the angle grinder and have painted the generator. The paint is a Rustolium and it is taking many hours to dry for some reason. I was hoping to get the magnets on the plates. I also still need the grease for the bearings before I can install them.

I still have a few things I would have done different that would have made it easier to make, stronger, and better looking. I also messed up my mesurements and the total diameter is going to be 3 1/2 feet not 4 feet... so 3.5x4.0 feet... fairly small still.

Todd a · « **Reply #13 on:** August 09, 2008, 11:34:38 AM »

Well I got the generator together.... sort of. Somehow I lost one of my bearings. After an hour of searching I gave up and ordered some more, so I am down for about a week. Without the bearing I do not want to measure the spacer size for the stator ring. I'm putting about 1/16th inch between each magnet plate and the stator ring. The thing that really sucks is pulling the plates apart to change the spacers between the magnet plates. The amount of pull is just insane. I can not seperate it by hand until I have about a 1.5" space between the plates. I am starting to worry this generator is going to be way to strong for this wind turbine. I am going to need longer struts and bigger blades I think. I will have to wait and see when I start testing though and this will likely have to wait another week.

TomW · « **Reply #14 on:** August 09, 2008, 11:40:08 AM »

Todd;

The bearing is on the bottom of the can of gasoline you used to clean it! Or, maybe on the nail you hung it on to dry?

Tom

vawtman · « **Reply #15 on:** August 09, 2008, 12:19:04 PM »

Hi Todd

Your lucky to only loose one of your bearings so far :v)

Mark

Todd a · « **Reply #16 on:** August 12, 2008, 06:07:05 PM »

Still did not find it, but I am hoping the new one comes tomorrow. I have also fried my multi-meter and dropped my 18v cordless off the roof and ordered a few things that did not work. I got the blades put together and am working on the final tidbits of the wiring tonight. I also made a short temp tower for testing (keeps the turbine about 12" off the ground). It should take me about 30 minutes to get is up and running when the bearing gets here.

Todd a · « **Reply #17 on:** August 14, 2008, 12:03:10 PM »

OK... I'm an idiot. Well I know you generally want 3 coils for every 4 magnets and run 3 phases. Well now I know why. I was going to run 4 phases on my 12 coils (16 magnets per plate) as I was running thinner wire than I lreally wanted and was worried about the voltage drop for the longer distance caused by the 4th coil in each phase of the 3 phase set-up. Well it did not work so well and I started thinking about it. With a 3 phase set-up I would have had all 4 coils in a phase sitting over the same pole magnets at the same time. In a 4 phase setup I have 3 coils, but one would be on a north pole, one on a south pole and one inbetween poles. They would be fighting each other... and that is what it did. The voltage was very low and wandered around a bit. I thought a bridge rectifier had shorted out, but even checking the AC output on a single phase did not show too well.

I also found the aluminum struts are a bit too springy, so I will switch to steel instead. It will make it a little heavier, but will be much stronger.

I also put the blades on the wrong way around and it did not spin much at all unless the wind gusted. I switched them around and flipped them over and now it actually starts spinning up slowly in as little as about 2MPH of wind... admittedly it spins VERY slowly. I also found that my house fan idea was not the best as the actualy wind speed after just a few feet is actually pretty low. It will spin it, but not much.

I can fix all these issues, but it will take more time. I have it ripped apart again and have the stator ring out. I made the connections on the inside of the plate and will try to chip some of the epoxy away so I can rewire the stator to 3 phases. I will also added 4 more blades for testing, but will stick with the aluminum struts for now.

One thing though... those bearing work really good and this thing spins with almost no pressure. There is mass, but almost no resistance. That part makes me happy. My temp tower for testing worked well too and actually made it much easier to work on the generater with it mounted. It took about 5 minutes to take off the 4 blades, seperate the magnets plates (not a fun task), and remove the stator ring. Hopefully Saturnday I will have it all back together with the stator ring fixed and the extra 4 blades added. Then I can do some real testing.

Todd a · « **Reply #18 on:** August 30, 2008, 12:50:07 PM »

Well I am still working on my VAWT and had to redesign the blades (after some more research and some smaller scale testing). The other thing was I had messed up on my stator and had wired 4 phases on a 12 coil set-up (16 magnets on each plate). Well I found out you need all the magnets on a phase hitting at the same time and with the same polarity. Well I tried ripping apart the stator and re-wriring it, but the epoxy was too strong and I only turned out with one phase partially working. The other problem is the wire I have available to me is too thin at 18g to run only 3 phases with enough coils to generate the power I am looking for....

Well I got a new idea. How about 5 phase on 20 coils. Each phase will have 4 coils and line up with the same polarity magnets, but only one phase is directly over a magnet set at a time to reduce cogging. In theory this should work fine. It also lets me have smaller coils, with 50 wraps each, connected together, for a total of 200 wraps. This is still about 83 feet of 18g. Well that is much shorter than if I did 3 phases with 75 wraps per coil, or 125 feets per phase. So if I can manage about 36v and 5 amps per phase I would hit around 900W. With 3 phases I might be able to handle aboutabout 500w (do to that amp restrictions of the 18g wire and the higher voltage drop of the longer wires).

Does this sound right?

I have 5 out of 20 coils done...

The lines on the paper are where the magnet rings are (16 magnets make up an 8" OD with a 4" ID). I will have only a little of the wire overhanging the 2" wide magnets.

News:

Author Topic: Cheating local zoning laws with a VAWT (Read 4469 times)