vertical axis wind turbine

[canid]

i'm working on a wind turbine design and am planning the rotor right now. i think i will be going with a vertical axis design.

i need to a new DC motor as the one i was planning to use simply does not cut it. if i can't find a good one i will be making my own alternator from handwound copper and neodymium magnets. ebay offers a good selection of these at a decent price and i found 6 cylindrical magnets of a usable size for $10. two orders of these will be enough for a suitable 3 phase design.

below is the rotor design i've settled on, which can be used on a vertical or horizontal axis and is not particularly direction dependent.

[Rick]

Canid - What in the world are you using 3 phase for? Are you running your own transporter or time machine? :rolleyes:

We ran 3 phase DC where I worked and the backup batteries were monsters. Every building had one room dedicated to the battery bank. That's going to up your overall cost considerably isn't it?

[canid]

3 phase into the rectifier makes for a smother current out to the batteries. wth that and a capacitor smoothing circuit, you could probably run most electronics directly from it. i have a feeling it's easier on the batters in the bank anyway.

[Rick]

All true and adds longer life to whatever you are running I was just thinking of the overall cost for setup and maintenance as well as the cost of equipment downstream. You could run a 12V military alternator into deep cycle batteries a whole lot cheaper.

What are the dimensions on the turbine? I'm just curious, ball park size is fine.

[canid]

looking like 6' high by about 4' wide, greatest dimension on the rotor.

i'm currently looking at winding my own alternator and picking up a 100v DC motor, whichever turns out to be next to free.

the difference in cost for the three phase will only be the couple of dollars difference in the rectifier.

[canid]

i've concluded i can build the rotor for about $15

[Rick]

Well, I have to tell you, that's pretty cool. Let us know how it turns out.

Canid: "Foolish earthlings. Once I have completed the atomicatomica I will rule their world. Muhahahahahah."

[canid]

i thought i might add-though it is obvious-that it would be easy to make a smaller rotor like this from a 55 or 35gal drum and an axle rod of some [read: almost any] type.

for bearings, i plan to use 7ball skate bearings on an 8mm axle. this makes them easy and cheap to replace when needed and gives the system a clean rotation.

[canid]

well; i haven't put anything into this project in a while, so i figured i'd get back to it.

i'm building a small-scale model for the Savonius rotor, but with 3 blades instead of two. i'll probably have to adjust the pitch on the blades before it is even remotely efficient.

i'm also working on a 3 blade rotor for a giromill type Darrieus turbine. i'm using coffee can walls for the rotors in buth turbines. i have not sourced bearings or rotor shafts yet, and am waiting on the motors i plan to use as alternators.

ideally, they will both drive small 2phase steppers from old 5.25" disk drives, with bridge diode rectifiers to smooth the output.

http://i602.photobucket.com/albums/tt106/canid/mechanics%20and%20such/IMG_0386.jpg
http://i602.photobucket.com/albums/tt106/canid/mechanics%20and%20such/IMG_0385.jpg

http://i602.photobucket.com/albums/tt106/canid/mechanics%20and%20such/IMG_0388.jpg
http://i602.photobucket.com/albums/tt106/canid/mechanics%20and%20such/IMG_0387.jpg

it is even harder than i expected to form an airfoil from currogated metal sheeting, and i am not done with the forming on the darrieus rotor yet, and have still to for a rotor frame for them anyway. i need to flatten and elongate them a fair bit, but still having such a high chord length to thickness ratio, i don't think tuning the pitch [angle of attack] will be all that critical.

i have not done anything about designing the stators yet either. they will probably be very simple.

[Winnie]

Canid have a look at this site. Not to buy or anything, but it may give you some design ideas etc.
http://www.secretenergyturbine.com/index.htm

[canid]

thank you.

for design ideas, i've basically been brushing up on basic fluid dynamics and analog electronics, researching performance for known models in various turbine types, reading and talking with amature designers online, etc.

for airfoil rotor types, i've found a few particularly handy resources, like this one (http://www.desktop.aero/appliedaero/airfoils1/airfoilgeometry.html).

[gryffynklm]

Canid, Do you have a schematic for your three phase circuit you would be willing to share? I just picked up three alternators to experiment with and was planning on a vertical axis turbine as well.

[canid]

no, because it will depend on the generator i end up using. for the models, i think it'll end up being disk drive steppers. for a full size unit, it'll be whatever i can scrounge or build.

3 phase:
http://www.reuk.co.uk/OtherImages/3-phase-full-wave-bridge-rectifier-circuit.jpg

1 phase:
http://www.play-hookey.com/ac_theory/images/rectifier_bridge.gif

wikipedia's diode bridge entry (http://en.wikipedia.org/wiki/Diode_bridge) also illustrates and explains single and three phase bridges.

the entry for VDCs (http://en.wikipedia.org/wiki/Voltage_doubler) looks interesting too.

[canid]

btw: automotive alternators have diode bridges in them, which i think are usually full wave.

these are examples of what the rectifier assemblies look like:
http://www.freewtc.com/images/products/small/9/01/35/13565.jpg
i don't know why this first one [from a motorcycle alternator i think] looks to have only 3 diodes.
http://www.f2motorcycles.ltd.uk/f2images/russian%20spares/l424_diode_pack.jpg

[crashdive123]

There's an auto parts store in town that is using three vertical axis turbines. Next time I'm near it, I'll snap a few pics and see what info I can get from them.

[canid]

do keep in mind that while i have only electrocuted myself a handful of times, and have never caused anybody else to come to harm, i have no formal background in electrical engineering...

http://i602.photobucket.com/albums/tt106/canid/webtemp/electrical_engineer.jpg

[gryffynklm]

Thanks Canid. That gives me enough info to keep looking at three phase. I wasn't familiar with that option.

[SARKY]

You guys might want to check out this web site, at least for the turbine design
www.aerotecture.com

[canid]

i like the crazy darrieus designs. i don't think i could easily and cheaply build something like that from scrap.

228Watt/Hour average is pretty darned good though.

[rebel]

Phases for weight, yea. 1000 piece puzzle, no thanks.

[klickitat]

windshield wiper motors and alternators are good sources of DC motors. Older Dodges also had generators instead of alternators.

I like your little turbine idea. You might be able to pick up a windshield wiper motor and hook it up directly to the shaft

[Winter]

That's really cool Canid and too smart for me.

back to my cave.

[NCO]

Caves have one advantage. Cavemen used to live in them when there was cavemen. Modern people didn't. Caveman wins...

[Rick]

I don't know why you couldn't use an appliance motor from a clothes washer or dish washer.

You could rig it up to sit on top of your heat pump or external air conditioner and capture the "wind" off of it. Let the fan on the heat pump power the turbine. You should be able to do the same thing with the exhaust off the dryer. Of course the scale would be a bit smaller but a couple of small turbines added together would add up.

[your_comforting_company]

This is a really great idea. I'm following along and have this thread bookmarked. I'm learning a lot from this. Thanks for sharing!

[canid]

ac motor needs a supply current to induce a field in the coils.

as for a couple of small turbines, i basically plan to keep designing/building improvised turbines whenever i can.

my actual needs for them are only to be able to charge some small batteries and power emergency lighting, but if i have the opportunity and extra cash to build a few of the full scale turbines, that would actually cut the power bill back, and easily be worth the while.

thanks for reading everybody, and for the comments.

[canid]

btw: vehicle alternators work, but not terribly well. by and large, they have a relatively massive iron core and stator, and tend to have quite high losses. remember: they are designed to produce just enough current to safely charge an automotive battery at 2-6k RPM. if they where more efficient for low speed applications, they would be a safety risk when run in a car.

[gryffynklm]

Thanks Canid, I didn't realize they were that bad. It still gives me something to work into a charging system. I can build my own alternator later. Besides with all the things on my list of things I want to do, I have no idea when or if I'll even start it. I do find the technology fascinating.

[Justin Case]

My Dad built a wind charger years ago,,,, he used 2 80 amp car alternators to charge a rack of big 1.5 volt batteries,,,

[canid]

if your turbine produced enough torque, i'm sure you could get an auto alternator to perform well enough with a suitable gear ratio. if i had a spare one laying around, and the extra materials to find out what the actual performance was, i wouldn't hesitate to try it.

[Justin Case]

Yes,, It was pretty big,, 5 , 5-6 foot blades,,, looked like an airplane prop. the "prop" was attached to a cut down car rear end , the drive shaft turned a big wheel that turned the alternators,,

[gryffynklm]

Ya thats going to be the problem, Large enough blades to overcome the torque necessary to get the rpm at the alternator.

[2dumb2kwit]

Ya thats going to be the problem, Large enough blades to overcome the torque necessary to get the rpm at the alternator.

I cheated. I used an old lawn mower. (Just replace the blade, with a pulley.)
It's not wind power, but itcan be a back-up for charging batteries.:innocent:LOL

[Camp10]

Let me think this through a little more and I'll PM you Canid...I'm not sure that your dc/ac conversion is going to be right. I might just be looking at the schematics wrong but your 3Φ open Y source doesnt work (in my mind) for this...I'll get back to you this afternoon.

[rebel]

You might get a bicycle generator to work with that thing.

[canid]

Camp: which circuit?

[canid]

well, i got the drives today. sadly; the head control steppers are even smaller than i imagined, so i doubt they'll produce enough current to charge a single 1.5v battery, but i'm still going to play with them.

i'll be on the look out for some tiny diodes [LED maybe, since i've probably got some of those hanging around]. i think these little things could easily be turned by a pepsi can savonius.

[canid]

Rick: i tried capturing the exhast from my clothes dryer, but i don't think it's working:
http://i602.photobucket.com/albums/tt106/canid/webtemp/clothesline.jpg

[canid]

ok, so i don't have two of these [yet] so i can test both sets of rotors side by side, but here is one of the alternators i'll be playing with.

it was originally a disk/pancake type motor build into a PCB controller for digital PWM control, but i've trimmed off all the excess PCB and components.

here's the rotor core:
http://i602.photobucket.com/albums/tt106/canid/mechanics%20and%20such/smallsavoniusrotorcore.jpg
and to illustrate the core's fields:
http://i602.photobucket.com/albums/tt106/canid/mechanics%20and%20such/smallsavoniusrotorfield.jpg

and the stator assembly after trimming and grinding away all the extraneous crap. i don't know why they had the coils on the side of the PCB facing away from the rotor core [and magnets], as it seems this would dramatically reduce the induction in the windings:
http://i602.photobucket.com/albums/tt106/canid/mechanics%20and%20such/smallsavoniusstatoraddembly.jpg
here is the stator with the PCB holding the coils removed:
http://i602.photobucket.com/albums/tt106/canid/mechanics%20and%20such/smallsavoniusstatorandcoils.jpg

i'm going to remove the coil contacts from the PCB and wire them through the stator out the bottom instead, so the remaining PCB disk will just be structural.

the six coils should let me have 3 phases with 2 coils per phase, and that will be run to the bridge circuit.

i'll be putting a couple of these together from the 3 1/2" drives i have laying around as well, but they are much smaller motors. the steppers where all so tiny that i can't think of a remotely practical alternator application for them. i'll still be playing with them anyway though.

[canid]

those 3 screws visible on the stator are going to be a light problem, as they won't allow the coils to sit flush. i'll have to bore a couple small holes in the PCB and probably use countersink screws instead, but we'll see what i come up with.

btw: the two leads coming out of the back of the stator are from an LED that was part of a feedback sensor for clocking the rotation speed. i might have a use for that later :D

[Rick]

Canid - You failed to properly align the cellulose bodies along the linear plane. The dryer output will can be controlled simply by the alignment. If used as they are you'll enounter vortexes that will impede uniform flow.

[canid]

you're right, i'll try to fix the alignment so i can achieve a laminar flow.

[canid]

i'm looking into the merits of a more complicated rectifier which is basically a wye and delta wiring for each set of 3 coils, with a full wave diode bridge wired in parallel. it should produce 6 pulses per set, offset by 30 degrees, giving 12 pulses per rotation. i'm having trouble with the soldering iron [which might be on it's way out], but i'll have it wired up soon enough. i still don't have the diodes i need yet anyway.

http://i602.photobucket.com/albums/tt106/canid/mechanics%20and%20such/3Ph2W12Pdiagram.png

[canid]

the benefit of doubling the pulses per rotation is a smaller ripple in voltage of the output current.

[your_comforting_company]

Smaller ripple = more streamlined output?
sorry.. still trying to follow along.. this is a little over my head.

I would think a steady output would be better on the batteries. Just guessing that you are trying to increase output without "shocking" the batteries into oblivion. Somewhat the same function as a capacitor, but internally rather than external and having to be seperately regulated? Hopefully I'm on the right track.. might not have said it right tho..

[canid]

yes, it means a smaller difference between the voltage at the peak and the trough of the output.

this is good for batteries, and it is also crucial for digital devices.

[your_comforting_company]

thank you very much for clearing that up! I'm an electronics dummy, but I'm learning and really enjoying this thread!

[canid]

for illustration:

http://www.ndt-ed.org/EducationResources/CommunityCollege/MagParticle/Graphics/ACWavesTABLE.gif

where the number phases are essentially independent waves which overlap, which means that the current is the top of the wave.

as i have it; the wye configuration maintains the amperage of the induced current, raising the voltage, and the delta does the reverse, so this 2 way wiring would basically combine the two, for balanced current output.

both are rectified by the diode bridges, which is what smoothes the output current. that is the part that serves the same purpose as a reservior capacitor.

i'm sort of an electronics dummy too, but i love to read and tinker.

[Rick]

But your going to achieve that anyway with the rectifier, aren't you? The output will be a DC voltage with a uniform sine wave, a constant frequency and amplitude. I guess you would have an issue with slow rotation, on no wind days, but once you get up to something like 1 rotation per second it becomes a mute point I would think. Blade length will be a determining factor on rotation speed as well and I don't know the actual size so I'm kinda commenting hypothetically.

EDIT: I was typing when you posted but your graph sort of illustrates my point.

[canid]

the doubling of the pulses [first from the rectification, then again from the offset between coils] increases the frequency of the fluctuation, and the straddled configuration of the two sets of windings [i think] is supposed to produce the maxima of both voltage and amperage.

[Rick]

I get what you're trying to achieve I just thought as long as your output was 12VDC or greater you'd be okay. I assume you'll also have a voltage regulator on the outboard side?

[canid]

if i get this finished and have a suitable output current, i'd like to try using it to supply a microcontroller [there are some on the market in the $10 range that can operate on 1.8v] and to charge a 1.2v Ni-MH battery.

until then, i have a good miltimeter, so i'll be able to get the basic output specs.

this mini version is going to generate a very low current. i have no clear idea how low yet, but we'll see before long. it was a 5v motor, so i don't expect much.

[Rick]

Okay, I'm with you. Sorry. I thought this was a bit larger version. Maybe I missed something posted above.

Still, it's a cool project.

[canid]

i had expected to be able to source larger motors is all.

[canid]

speaking of larger design: i was able to source 10 cylindrical NdFeB (neodymium) grade N42 magnets about 3/4"dia. by 1/4" high. when i can, i'll be ordering a second set, giving me enough for 2 or 3 alternators, so i'll be able to build larger turbines after all.

i have some larger copper wire which may be too large for efficient coils for use with these, but otherwise, i'll strip the smaller stuff off of one of my burnt motors.

i should also be able to buy the diodes for the rectifier circuitry soon.

the disc motor turbines i've stated on will also continu once i can replace my soldering iron and get some fresh solder.

everything went back on hold for a few, but i'm still on the job.

[canid]

made a couple more bucks on my mTurk account and was able to order the solder. couple more days i should be able to get my new iron and the diodes. they aren't expensive, but would probably be cheaper if i waited til i had at least $25 and ordered a couple things at once to get the free shipping.

what i can't scavenge, i'm buying with amazon money, since it's easy to earn a couple bucks here and there with them and doesn't take any of my in-hand cash. sort of the way i did the garden the year before last with my recycled junk and bottle/can recycling money.

[your_comforting_company]

Have you looked into junkyards and scrap iron places? Magnets are in lots of things we use, like microwaves, speakers.. Not sure if that is a viable source or not, just a suggestion. speakers have a lot of fine wire in them too, for voice coils.

I may have missed in an earlier post, but are you thinking of using 55gallon drums for the larger scale? Sometimes you can run up on a barrel around machine shops (I got a couple from local industries).

I don't want anyone getting the idea that I know anything about this stuff, but I'm really interested and I want to help. If I lived in your neighborhood, I'd be at your house every day... We'd never get bored!

[canid]

ceramic magnets are in lots of things we use. NdFeB magnets are far less common in manufactured items.

i am happy to scavenge whatever i may, but in magnet selection, quality [in terms of maximum gaus per volume] is key. it means being able to get several times the inductance in a given winding of coils.

i have considered steel drums, because of their availability as a waste item and low cost, but i am also open to other options if i can find a suitable alternative.

with a heavy rotor - as such a drum would yield - you would have a higher starting wind speed, meaning that it would require higher winds to run at all. with suitable alternator design, this would allow you to target your system to the higher end of your area's wind speeds [and be a little less prone to generating overcurrents in high wind conditions and gusts], but your system would be running less often. with a lower starting speed you would have the inverse problem, producing your target current range in lower winds, but needing overcurrent/overspeed protection in high winds.

it's just about finding the balance that meets your power needs most of the time, and does not exceed the limits of your system.

[crashdive123]

Canid - not sure if it helps or not, but as promised here are some pics of turbines used at a local business. Even did a Youtube for ya.

http://i261.photobucket.com/albums/ii67/crashdive123/Out%20And%20About/WindTurbines006.jpg

http://i261.photobucket.com/albums/ii67/crashdive123/Out%20And%20About/WindTurbines007.jpg

http://i261.photobucket.com/albums/ii67/crashdive123/Out%20And%20About/WindTurbines008.jpg

http://i261.photobucket.com/albums/ii67/crashdive123/Out%20And%20About/WindTurbines009.jpg

http://www.youtube.com/watch?v=-UtXwhu8iyA

[Rick]

I was looking at some similar designs this morning. Each of the vertical "fins" is little more than an air foil. However, a convex surface on the exterior with a concave surface on the interior should work as well. You could use something like PVC pipe cut in half length wise and placed vertically to do the same thing and reduce the overall weight.

Good pics and good vid, Crash!!

[crashdive123]

I just called the company that put them in. They each put out 1.2KW/HR and run approximately $15,000 each.

[Rick]

Wow! Based on that I'd break even in 9.398 years if I run 100% off of them.

[canid]

crash: that's a gyromill [a type of darreius rotor]. same concept i have in mind [though with different geometry of course] for my little darreius.

[canid]

doing your own fabrication, and doing it smart in your own time, you could build a gyromill of about that size and output for probably 10% of that cost.

[canid]

My magnets got here today.

I had a bit of trouble with my diode order. it seems if you don't have a credit card or checking account paypal won't let you use your ballance at all, even if there's money in your paypal account itself. I found this out after trying to buy a cheap 100 ct. package of diodes with plenty of money in my account for it, when paypal would not let me pay.

now i have to wait til i can get a visa prepay to re-verify my account with.

I'm darned happy with these magnets. Anybody who hasn't handled N42 or higher grade magnets might be fooled by the junk some compayies sell, but when you have the real deal in 1/2 cubic inch size or larger; you can't actually play with them without risk of breaking them.

[canid]

no dice on the windings from that old motor. they are cast into the core in such a way that it would be extremely difficult to liberate them, and i found out what had burned out the motor before it was given to me: a large wasp's nest caught fire and burnt the heck out o it.

i did score a nice reset relay and three large diodes from the deal: too large for the rectifier i'm building, but certainly large enough for a much larger project later.

i'm still on the prowl for materials, and i'm half way there.

[your_comforting_company]

Sounds like things are slowly coming together. Keep at it and I know you'll get it. might be a test of patience...

[canid]

the last 5 years of my life have been a test of my patience. it's ok; i'm not too bad at tests.

[canid]

no particular progress at the moment, but i have managed to hurt myself with these magnets a couple of times now.

[Rick]

Would you consider changing your avatar to

http://www.marlerblog.com/uploads/image/Cow-Pie-3.jpg

I find it in much better taste and I'm less inclined to find a tall structure and start shooting after I look at it.

[crashdive123]

no particular progress at the moment, but i have managed to hurt myself with these magnets a couple of times now.

At least you didn't eat them.

http://i261.photobucket.com/albums/ii67/crashdive123/Forum%20Fun/refrigeratormagnets.gif

[canid]

oh, i made the mistake of sticking the whole stack to the fridge yesterday.

for perspective, it takes much of the strength in both hands to separate one from the stack without spacers in between them.

[Rick]

Odd, I feel that life is somehow in balance this morning and my eyes don't hurt.

[canid]

ok; i'm definitely going to have to go with a simpler rectifier in the smaller turbine/alternator designs. with the best cheap schottky diodes i think i'll be able to get my hands on the forward voltage loss will still be too high otherwise.

[canid]

soldering small thru-hole components to pcb with a 120watt weller is a huge PITA.

[your_comforting_company]

try swapping the standard tip with a short piece of wire clothes hanger. The smaller tip size helps me sometimes with little remote wires and such. I loves my 120W Weller.

[canid]

i'll try that, or something similar. i bed several strands of resistance wire twined together would do.

i'm still on this. i've made up a small 3phase diode bridge [though i think i may have gotten two of he diodes on the board backwards], so i just need to test that, check all the solder points and tie it to a 3phase brushless dc motor and spin it up.

i'm re-enforcing the coffee-can savonius rotor with some fine steel rod.

i've been dragging my feet on this project for a while, but i've also started a fair number of other projects which might be more immediately usefull [SMAW welder, battery charger for my bike, etc.]

[canid]

here's the small 3phase diode bridge:

http://i602.photobucket.com/albums/tt106/canid/electronics%20and%20such/th_IMG_0183.jpg (http://s602.photobucket.com/albums/tt106/canid/electronics%20and%20such/?action=view&current=IMG_0183.jpg)

http://i602.photobucket.com/albums/tt106/canid/electronics%20and%20such/th_IMG_0184.jpg (http://s602.photobucket.com/albums/tt106/canid/electronics%20and%20such/?action=view&current=IMG_0184.jpg)

[canid]

careful with capacitors my friends. i was taking apart a junked camera just now, and i though to myself: what's the safest resistive medium to discharge a 330v, 80uF capacitor? and then it hit me: 'it' being 330 volts dc through my thumb.

not terribly dangerous, but it'll wake you up in a hurry. i may have invented a replacement for coffee.

[hunter63]

I have a "designated screwdriver" for that....Doesn't take long to "look" (pick it up)at it when that happened.

Guy got killed fixing a microwave a year or so back, trying to help out, or so the story goes.

[canid]

yeah; i've got a couple of those big ones. i used a large inductor (on the end of a wooden handle) to make sure those where discharged.

if you just bridge them to a screw driver, you can weld the screw-driver to the terminals, not to mention ruin the cap and the screwdriver.