DIY 1000 watt wind turbine

We built a 1000 watt wind turbine to help charge the battery bank that powers our offgrid home. It's a permanent magnet alternator, generating 3 phase ac, rectified to dc, and fed to a charge controller. The magnets spin with the wind, the coils are fixed, so no brushes or slip rings necessary.

Step 1 Build the magnet disks

We had 12" steel disks hydro cut. We cut a template for mounting the magnets. Then we mounted 12 grade n50 magnets around the outside edge. We then built a form, and poured the resin with hardner.

Comments

[Anything Possible]

A lot of good ideas here. Let me share something with all of you.

Neo #50 magnets are too powerfull to be put in this pattern as pictured above to get the most out of what they can deliver when matched with a coil sandwiched between. You are simply creating a magnetic field that is too intense for the coils to provide electron movement efficiently.

Brake Drums: Brake drums are metalic and heavy. You only increase eddy currents by using this type of material and thus increase the load/heat.

Bearings: everyone is using wheel bearings. These bearings take a lot of energy to rotate and rob at least 35% from the rotation energy.

If you want more tips, Let me know...

Anything Possible:

[sspence]

We are using n45 and n50's, but not brake drums. We use lightweight 1/4" steel plates. We are using harley wheel bearings.

[johnvro]

Thank you very much for this great project.

I'll be building one following your instructions, being in the part/material gathering stage, I wondered whether you have preferred supplier for the 14 ga. copper wire.

TIA

John

[sspence]

http://www.forcefieldmagnets.com/catalog/advanced_search_result.php?keywords=wire&x=0&y=0

[johnvro]

Thanks my friend, will keep you updated on my progress once I get started.

[vbe44bfm]

Have been following this for a long time, so I have some questions:
a) can I use cylindrical magnet with pole on circular face, what is the difficulty in mounting - as these magnets will be in rotation? Say, if the height of the cylindrical magnet is 15mm how much of it shall protrude over the disk - can it be flush mounted? Can I use bulk thin CRGO sheets rivetted to make a magnetic core?
b) can I somehow add soft iron cores for the coils to concentrate the flux, should it be contiguous like that in the magnet disk or soft iron core for each coil
Though these arrangements if made as above will make the system a bit heavier does it have any advantage on scale of 1-5 over your setup?

[sspence]

a) yes, you can use cylidrical magnets, btu this will change the shape of your coils.

b) adding iron cores will increase cogging, preventing startup at low wind speeds.

[vbe44bfm]

Thanks SSPENCE for the reply (sigh - waited till it came), but can I use CRGO / CRNO riveted sheet for magnet disc - doubt loss of flux in this scheme or of no significance? What s the minimum & maximum air-gap you maintain? I am also thinking of experimenting with small RC inrunner / outrunner brush-less motors - supposedly they are of similar principle & can be used for small scale projects before my magnets arrive. Is there a simple way (tests) to tell the difference between n48 and n50 grade nefeb mags conclusively.

[sspence]

I've never tried laminated sheets for the magnet disk. I maintain the smallest gap I can without the two pieces "kissing". This is about 1/8" for me. I don't have a Magnetometer, but I think one would give you the info you are looking for.

[Celtophiliamike]

I apologize if this question sounds naive, but what is to stop you from putting another set of disks behind the first one and generating more power off the same amount of wind? Assuming the disks are fairly well balanced, I can't see how it would take much more wind to turn.

[sspence]

The loads determine the wind, not the number of disks. The more power you consume, the more resistance the wind will have to overcome. You can add more rotor/stator packs if you wish, but start with one until you understand the process.

[lecaonguyen]

Looks very professional, but achieve AC voltage before the rectifier is how much? and the treatment you how the absence of wind (low voltage). Please reply to the email [e-mail]

[sspence]

It's not professional, it's a backyard hack ;-)

The ac voltage is determined by the number of turns in the coils, and the wind speed vs. load. If the voltage is too low, the batteries do not charge.

[jsierra4]

Great Generator!! I am actually creating a hydro one my self based off your idea. One question I have is how do I create the device to wined the coils.

If you don't mind can I email you if I have anymore questions?

[sspence]

just made a simple wooden form. feel free to email, [e-mail]

[wndwalker]

(removed by author or community request)

[sspence]

We built a dual rotor unit. only the magnets need to turn, not the coils. Was more complicated, and required quite a bit more wind. Longer blades would be necessary. There is also the possibility of counter rotating the coils from the magnets, increasing apparent speed.

[Gary Frank]

Howzit...I've been wondering about the mechanics in a dual rotor system. I take it that you have 2 coil stators and 3 magnet rotors???
If so....how is the magnet setup on the middle rotor. Do you have a steel dics with magnets mounted on both sides or a disc with cut-outs and magnets mounted centrally in the disc? I dunno if I'm explaining it properly, but I'm looking at saving magnets and keeping it as compact as possible - I need to mount this in a motorcycle rear rim. Could you post more information on your dual rotor setup?

[sspence]

3 disks, magnets are either side of the middle disk.

[Gary Frank]

Sorry...meant to say dual stator system...

[wndwalker]

thanks for the reply, So..it would be better to have more than 1 unit if you wanted to increase electric power output, as a bigger w/ longer blades etc.unit requires more wind I would assume.

[sspence]

Longer blades, require less wind. See http://www.green-trust.org/windpowercalc/

[Mrdman2442]

By wiring the alternator in star you sacrifice some current output. My thought would be wire each phase separately to a bridge rectifier then combine the DC output from the 3 rectifiers in parallel. Is there something wrong with this idea?
I am building a vertical turbine with a savonius (starter) inner rotor and a larger H type main rotor on the same shaft. With this setup in low wind, below startup, the turbine will still be turning and by connecting the rectifiers in series I could get usefull voltage at low current. When the winds pick up the rectifiers will be switched back to parallel so the main rotor can kick in.
Is this possible, or is there some reason 3 phase is only wired in star or delta?

[Mrdman2442]

Do you have an idea of how feet of magnet wire you used? Thinking about useing aluminum wire as its cheaper but I need an idea of how many feet to buy as the weights are different.

[sspence]

aluminum doesn't handle current as well, so you'll need to derate accordingly. I used about 200' of wire, but that's dependent upon voltage and current needs.

[tkuhns]

I built the stator using double stranded 14 guage magnet wire - 35 turns per coil 9 coils and wired in the star pattern (did not flip the coils) with 2 - 14" disk rotors magnets alternating - 3 phase rectified with 2 40 amp bridge rectifiers. With no blades attached I spun the rotors by hand and with voltmeter under no load was able to obtain 3 vdc.at maximum speed (no idea how many rpms) Is this a reasonable ouput or would you have expected the voltage to be greater than 3?

[sspence]

on a 12v unit, you should see about 16 v or so above 200 rpm.

[mcsk8rg]

why do you need to rectify teh current comming from the coils ??? you can just connect all the +ve n -ve terminals of the coils n you are done !

you can get current directly from ALL the coils all at once !

[sspence]

There are no + and - terminals on the coils. It's 3 phase AC. Diode bridge is necessary to convert to dc.

[leozzito]

HI guys, very very nice job!!
Just a couple of questions.
Regarding the steel for magnets, can I use some old vinyls?
What is going to change if I use a steel of 10'?
Thanks in advance for your time!

[sspence]

You mean the backing plates? Has to be steel to complete the magnetic flux.

10 feet? That's a huge rotor ......

[leozzito]

Thanks for your reply...

I mean 10 inches...or 20 cm.
I understand that I cannot place that kind of magnets because of big dimensions, so I will need smaller magnets. But what happens if I place these 12 magnets (same as your project) in a bigger steel plate?

[sspence]

less powerful or smaller magnets make less power. bigger gaps between the magnets reduce power.

[rairwin]

how many of these disks would i need to put together for a 55kw gen.

[sspence]

one, if you make it really big.

[Ramos2]

Hi!! congratulations for your work! I'm going to construction a similar for my course. But I have some quastions. What the measure of magnets? If i buy smaller number (for exemplo N35) the magnect power is less?

Thanks!

[sspence]

yes, the lower the number, the less the power.

[Ramos2]

Thanks for the reply, you can tell the measure of the magnet you use?
This magnet is standard measure or you cut? thanks

[sspence]

2" x 1" x .5" N45 - N50, standard magnets.

[Walks-In-Storms]

I've built, and am running, a Lenz-type (modified significantly) turbine. Works fine, but I'm fishing (excuse, please) for ways to improve. I've wound nine coils, 44 single strands of AWG 15 wire, which starts generating 13.6 (charging) volts only at wind speeds of around twenty-five mph. I need to do better, but nine coils with two strands of AWG 18 wound 64 turns (128 turns, total) doesn't do much better. My math tells me I can't go much thinner (AWG size). I'm having one hell of a time getting it all in a stator 8" in diameter and 1/2" thick, besides - so I'm designing another "winder" made of steel (instead of plywood). I'd be very grateful for any advice you might be so kind as to offer. Thanks!