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Wind Generator with Hard Drive Magnets
By mrkooo, Section Wind Posted on Sat Sep 24th, 2005 at 03:24:46 PM MST
My first wind generator in progress

I'm from Peru, South America, I've read and learned a lot from this forum. I decided to build my first wind generator. No problems with the blades, they are 1m each (2m diameter rotor), I try them without load and work fine, very happy when I saw running so fast. But with the alternator, is anoother story, is very hard to get the magnets here in Peru, so I used HD magnets, I broke them in 2 pieces in order to have one pole. The problem is that nopw I have very little magntes. My winds are #21 wire and 160 turns, I expect to obtain al least 12V to charge a battery.
Any suggestions or comments to get the most power from this configuration?.

Blades without alternator, just a test, I can´t see the blades when running.

Double rotor with 16 poles

My wind former

12 winds, #21 wire, 160 turns
Thanks for everyone
Francisco

Wind Generator with Hard Drive Magnets | 44 comments (44 topical, 0 editorial)

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#1)
by ZooT on Sat Sep 24th, 2005 at 10:43:02 AM MST
(User Info)

I know very little about gennies, but just looking I'll have to say that the air gap between the rotors is "way" too wide.
I don't know if you'll be able to get the air gap narrow enough unless you either get thinner nuts or cut/file the nuts thinner on the threaded rods...

From what I've read at O.P. and other sites the smaller the diameter of the wire in the windings the higher the voltage (due to being able to fit more turns in a given area) created with a decrease in amperage and wattage.

If I'm wrong here, somebody please correct me.....like I said, I know VERY little about this stuff

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#5)
by hiker (hiker(at)adnmail.com) on Sat Sep 24th, 2005 at 02:47:40 PM MST
(User Info)

use thicker wire[#16or17]--75-85 turns should work out..make the hole in the coils about the same size as mags[a hair smaller is okay]..make the stator 1/4" thick,and you should get the max from your mags and coils..

heres a shot of my old 1/4" thick stator..single phase..coils inlaid in wood.

and a little box fan alt.powered by harddrive mags--single phase..[easy 10amps]

WILD IN ALASKA
[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#2)
by Jon Miller (Fieldlines 'at' otherpower 'dot' co 'dot' uk) on Sat Sep 24th, 2005 at 10:44:21 AM MST
(User Info) http://www.otherpower.co.uk

Now the only thing i needed here is a picture of your complet windings in there casting. The problem sounds like you might have wired the coils up the wrong way and so all the emergy is going into producing heat and not electricity. Pleas posed a pic of the coils in the cast (or however you have set them up).

.
Jon M www.otherpower.co.uk

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#3)
by electrondady1 on Sat Sep 24th, 2005 at 10:47:47 AM MST
(User Info)

perhaps another layer of magnet pieces could be added to each disk to increase the power.

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#4)
by henjulfox on Sat Sep 24th, 2005 at 12:55:07 PM MST
(User Info)

If I read you right I believe you have a fundamental problem with your magnets. You say you broke them in half to get 1 pole. When you break a magnet into half, or any number of pieces, you get smaller magnets with 2 poles each. I believe the problem with using hard drive magnets is that the poles run the length of the magnet when what you need is magnets that have poles on the face.
I believe there are a few posts here of folks using hard drive magnets.
Except for the magnets it looks like a beautiful set up. I'll bet our hosts would be happy to sell and ship you some magnets.
Good luck,
-Henry

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#6)
by electrondady1 on Sat Sep 24th, 2005 at 02:51:35 PM MST
(User Info)

just just had the lab. double check my findings.( oh yea!)there are two poles per face one at each end .he's got it right.but isn't it standard to have the stator thickness about the same as one mag?

[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#8)
by hiker (hiker(at)adnmail.com) on Sat Sep 24th, 2005 at 03:39:54 PM MST
(User Info)

nothing wrong with breakin the mags in half--his had both poles same side up--
when broke in half you end up with north on one side and south on other..
been there.............
WILD IN ALASKA
[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#9)
by henjulfox on Sat Sep 24th, 2005 at 04:20:38 PM MST
(User Info)

Thank-you! I didn't realize they were magnetized that way. I'm sitting here playing with a HD and neo and you are certainly right.
-Henry

[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#7)
by mrkooo (mrkooo@hotmail.com) on Sat Sep 24th, 2005 at 03:02:19 PM MST
(User Info)

The problem with HD magntes is that the have 2 poles per face NS and in the opposite face SN, but when you break it in 2 pieces you get a magnet with one pole per face and the oposite pole in the other face. Thats what I have with my broken HD magnets and I can probe it when they atract or repel with the same or diferentes poles.

I drawed a 1:1 scale design for my stator, this weekend I will work on it.

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#10)
by electrondady1 on Sat Sep 24th, 2005 at 06:10:27 PM MST
(User Info)

have you done a test on a single coil yet?

[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#11)
by Ungrounded Lightning Rod on Sat Sep 24th, 2005 at 09:38:39 PM MST
(User Info)

Instead of breaking the magnets in half, why not just lay them out along the circumference of your rotors?

Space them maybe a fifth of their length apart as you go around the circumference (1 unit gap, 2 units north pole, 1 unit effective gap in the middle of the magnet, two units south pole). You'll have more poles for a given radius - which is GOOD. Rasies your frequency and the voltage (because the effective risetime of the field is shorter), lowers your cutin speed. The polarity of the magnets comes out right for a dual-rotor if you position them so the bodies of the magnets are opposite each other.

Expand your radius and use still more magnets for more power, or to let you use more and thinner coils so the gap can be reduced and the field strength increased.

[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#41)
by duden (mprism@ntlworld.com) on Thu Dec 29th, 2005 at 10:28:47 AM MST
(User Info) http://frenchstudio.co.uk

Further to your idea about using complete magnets, what about using the magnets in pairs. If you connect N-S, N-S in that order you will get a larger magnet. If you then double the diameter of the rotor, you should get a lower revving generator for a given output voltage. The coils can also be better matched to the size of the magnets.
It will be necessary to double or treble the number of magets thickness wise so you obviously need a lot of drives.

[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#12)
by hiker (hiker(at)adnmail.com) on Sun Sep 25th, 2005 at 04:09:41 AM MST
(User Info)

nice coils--but i still would go with thicker wire and less turns...
the way you have it set up now you will get high volts --but very low amps[if any].

rewind your coils with less turns if your going to use the same size of wire and you will get a few amps[amps is what its all about] and go with a 1/4" stator thicknes..
just my thoughts..again...............
what phase are you going for?-- single or more....
WILD IN ALASKA
[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#13)
by hiker (hiker(at)adnmail.com) on Sun Sep 25th, 2005 at 04:11:13 AM MST
(User Info)

nice blades
WILD IN ALASKA
[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#14)
by Jon Miller (Fieldlines 'at' otherpower 'dot' co 'dot' uk) on Sun Sep 25th, 2005 at 05:09:09 AM MST
(User Info) http://www.otherpower.co.uk

Probably best to do a single test on one of the coils and find out what you get. to be honest (and I made this mistake) you should build the PMA and then design blades to power it, not the other way round like you (and I) have done as this limits the power as if the blades are to big they spin to slow and if there to small they won't have enough torque to turn in lower wind speeds.

Basically do a single coil test and see what you get then come back to this post or another one and tell use what you get. From this we can help more.

.
Jon M www.otherpower.co.uk

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#15)
by mrkooo (mrkooo@hotmail.com) on Tue Sep 27th, 2005 at 01:12:54 PM MST
(User Info)

I made a test with one coil, but I think I did'nt make it right because held the coil with one hand and spind the rotor with the other then I watch the meter and read 0.8V but I had to use a big air gap to avoid touch the magnets with the coil, remember I was holding it with my hand and it isn`t very firm.

So I spect more V with a thinner air gap, hope so. I know that maybe I not going to reach 12V but I want to try it in the time a get a bigger magnets and make a new Genny

Thanks Francisco

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#16)
by electrondady1 on Tue Sep 27th, 2005 at 03:10:50 PM MST
(User Info)

hello mr. kooo,
yesterday i went to some computor stores and got 7 old harddrives. now i have neo magnets . i have been experimenting for about 1 year with ceramic magnets to understand the process of generation. i found out the hard way to test the coils with the same clearance and speed as will be used in the finished genni. you can do testing with one mag. rotor , cover it with a disk of paper or cardboard that is the same thickness as your intended clearance.what ever power you get with one disk will be double with two.

[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#17)
by mrkooo (mrkooo@hotmail.com) on Tue Sep 27th, 2005 at 03:48:59 PM MST
(User Info)

Good idea electrondady, I will try it that way. Tomorrow I will cast the estator with resin. That will let me have almost finished all the windgenerartor. I can't wait for it.

Thank for your advice
Francisco

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#18)
by electrondady1 on Tue Sep 27th, 2005 at 05:12:42 PM MST
(User Info)

check out danb's post for monday . he uses some glue and fiberglass to make shure the coils don't move around when does the stator.

good luck!

[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#19)
by mrkooo (mrkooo@hotmail.com) on Fri Sep 30th, 2005 at 09:53:21 PM MST
(User Info)

Finally I cast the stator, I forgot to use wax, had problems to get it off the mold, but it'ok.

Now is installed with the rotors, when I spin it with my hands I have 7.2 per phase. I thinking to wired it in star configuration, how much volts you think I will get with 3 rectified phases. Its ok to connect it in star or delta with this volts per phas. I want to char a 12V battery. One phase has 4ohms.

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#20)
by ghurd on Sat Oct 1st, 2005 at 02:04:08 AM MST
(User Info)

I am surprised with the 7.2V. Good work!

Have you considered rectifying each phase seperately?
Like 3 single phase generators in one stator.
I have a feeling with 4 ohms per phase, and 7.2V at low RPMs, it could work out much better.

I also have a feeling the blades might be too long. Shorter blades of the same design will run faster.

Only 16 (Only 16!) more hard drives will give enough magnets to increase the output, stacking them 3 thick on both rotors. Or 8 hard drives and place all the additionial magnets on the same rotor. The air gap to magnet ratio will be better.

G-

[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#21)
by mrkooo (mrkooo@hotmail.com) on Sat Oct 1st, 2005 at 07:03:02 PM MST
(User Info)

What is the differences between connecting it in star than seerately each phase. What advantages and disadvantages.
I think that maybe more V if after rectifying the 3 DC I connect it in series than if I connect it in star. And what about the amps?

Thanks
Francisco

[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#22)
by electrondady1 on Sun Oct 2nd, 2005 at 07:34:07 AM MST
(User Info)

hello and congratulations mr.koo.
i have had good luck. in another town, i got 8 more harddrives from the computor stores there .
some harddrives contain only one magnet which is double thickness. i intend to use these magnets as the default thickness.others will need to be dubble to match.

gurd, i asked this question in hikers post. what about a coil for each pole (single phase) but three layers thick,= three phase?

[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#23)
by mrkooo (mrkooo@hotmail.com) on Sun Oct 2nd, 2005 at 08:49:42 AM MST
(User Info)

elctrondady, how you are planing to make the alternator, breaking the magntes in two pieces or with the 2 poles per face.

[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#24)
by electrondady1 on Sun Oct 2nd, 2005 at 09:30:50 PM MST
(User Info)

its more work, but if i cut them up i will have more control over the size and shape of the coil. i like long coils

[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#25)
by electrondady1 on Sun Oct 2nd, 2005 at 10:20:11 PM MST
(User Info)

one thing i noticed, there seems to be a lot of different thicknesses ,

[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#27)
by ghurd on Mon Oct 3rd, 2005 at 08:28:50 AM MST
(User Info)

The 3 layer thick stator. Look around here for overlapping coils, or a 12/36 arrangement, and look at windstuffnow Ed's 18/27 "Alt from scratch". Better suited for a single-rotor, or maybe with real thick magnets, due to too much material at the top and bottom of the coils.
Also have a look at Ed's old post '3 phase vs. 3 phases' it might be called.
I have a single rotor 6/9 or 8/12 about half done. High hopes. Too busy to get more done for a while.
Just finished last years taxes(!) last night. 2 extensions, No kidding.
G-

[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#26)
by ghurd on Mon Oct 3rd, 2005 at 08:13:17 AM MST
(User Info)

I had a couple projects with too high resistance, too many coil turns, and too low cut in speed.
They worked better rectified seperatly, like 3 seperate single phase generators in 1 stator. Normaly it is not the best idea.
G-

[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#28)
by electrondady1 on Tue Oct 4th, 2005 at 07:26:30 AM MST
(User Info)

the last two i built were disapointing as well, but they were both experiments so i won't let that stop me . i learned alot !

[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#29)
by finnsawyer on Tue Oct 4th, 2005 at 08:33:56 AM MST
(User Info)

When he mentions rectifying each phase separately I think he means running each phase through a diode (rectifier) to a capacitor to set up the output voltage for that winding. The three outputs are then stacked or added to form the output voltage to the battery. This should get you the maximum voltage possible for a given alternator rpm. We recently went through a discussion of the merits of such an approach. Check my recent comments to track it down and find a schematic for the circuit. Just keep in mind that there are no single answers in electronic design. You have to tailor the design to fit your needs.
GeoM
[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#30)
by electrondady1 on Tue Oct 4th, 2005 at 02:44:04 PM MST
(User Info)

hello fin, how you doing? i think i follow gurds method. instead of going star or delta he's turning the output of each phase into dc and then combining them , i'll try to find the post you describe. am i right in thinking the dc can be combined in paralel or series?

[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#33)
by finnsawyer on Wed Oct 5th, 2005 at 10:12:05 AM MST
(User Info)

Yeah, you can combine dc voltages in series at will if they are floating (neither one is connected to system ground - well one can be). Parallel, no, as you can get nasty circulating currents if there is a slight imbalance in their values. But one can work around that by adding resistors to the circuit. Anyway ,here's the schematic:

The capacitors are necessary for proper operation. Without them you will have the three phases adding, which gives zero voltage at all times. System ground would normally be at the bottom. The resistor represents the load. Without the capacitors the mid connections go nowhere. I feel it's important for people to understand that the dc voltage has to appear across something in order for it to be stacked with another, so I dug up the schematic. Sorry about the size. I'm beginning to think that this stuff should be put in a FAQ for easy reference.
GeoM
[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#34)
by ghurd on Wed Oct 5th, 2005 at 10:31:48 AM MST
(User Info)

Yes. Each phase full wave rectified. Then paralleled to the battery.

Just sounds to me like, was it 7.2V(?), at low speed by hand, combined with 4 ohms per phase, that if it was wired in star it might be a better at higher voltages than 12V. I could be way off, it's all based on reverse enginering of my failures.

G-

[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#31)
by mrkooo (mrkooo@hotmail.com) on Tue Oct 4th, 2005 at 05:45:44 PM MST
(User Info)

By the moment I had connected it in star and rectifing with 3 bridges diodes. I going ti test it and then change to rectifying each phase separetly and then connect it in parallel in order to get more amps. All depents in the cut in speed to decide which configuration.

Electrindady if you built a genny with HD magnets I would like to see your results. Will be great if you could find a way to get the most power of them. You know HD are the only easy source of magnets for me.

Thanks
Francisco

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#32)
by electrondady1 on Wed Oct 5th, 2005 at 05:48:30 AM MST
(User Info)

mr. koo i have 22 hd mags but they are 3 different thicknesses not enough of each to do a rotor. the mags are strong.it seems a waiste to let them go to the garbage. two stores will save them for me . when i get a lot i will decide on a design.

[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#37)
by electrondady1 on Wed Oct 5th, 2005 at 08:16:53 PM MST
(User Info)

picked up three more harddrives to day on the way home from work. mr koo , did you have any trouble with the magnets making sparks when you cut them?

[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#35)
by mrkooo (mrkooo@hotmail.com) on Wed Oct 5th, 2005 at 11:43:33 AM MST
(User Info)

Just a question about something I never read anything about. Maybe because is to easy.

What happends with the cables that goes down from the tower when the direction of the windmill change looking for the wind? They get twisted and twisted until they cut.

How to avoid the turns of the mill in the cables?

Francisco

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#36)
by ghurd on Wed Oct 5th, 2005 at 02:07:29 PM MST
(User Info)

In clean air they do not turn all the way around very often.
I had one that did not turn around once in a month.
Moved it to another area with strange winds, between houses and trees, and it turned around maybe 20 times in a few hours. Part of the problem could have been because the tower was not level.

[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#38)
by ghurd on Wed Nov 9th, 2005 at 07:32:54 AM MST
(User Info)

How is this working for you?
G-

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#39)
by mrkooo (mrkooo@hotmail.com) on Wed Nov 9th, 2005 at 03:24:22 PM MST
(User Info)

I just finished the shunt regulator, I did some test and work fine with the genny. It´s making 120W, 450 rpm max. I´m thinking on making a shorter blades (0.7m) to get more rpm. I think the blades are too big for this little genny.

When I have all set up I will post more photos

Francisco

[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#40)
by ghurd on Wed Nov 9th, 2005 at 08:50:54 PM MST
(User Info)

Making 120w is good!
I also believe the blades need more rpm.

The blades look not twisted in the photo.
Twisted blades work better and faster.
(The worksmanship is very good for the existing blades.)

There are good photos here of Zubbly's twisted blades.
http://www.fieldlines.com/story/2005/5/17/16437/9630

Notice how the change at the root is rapid.
The change at the tip is very slow.

Windstuffnow Ed's blade program may be a good investment for US$5.
It works with blades under 1 meter. Many blade design programs not good for blades under 1 meter.
G-

[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#42)
by dastardlydan (dastardlydan1@verizon.net) on Mon Jan 23rd, 2006 at 01:42:40 PM MST
(User Info)

Mialo saw your posting about , using HD magnets ,
have you finished it and how dose it run.
what is your cut in speed,what size wire how many turns.
I have done lots of drawing and not sure?
My name is Dan ,I live in western Florida
Dastardly Dan Mckinney
++++++++++++++++++++++++++ DastardlyDan . This is only a test, had it been the real thing , you would have got instructions.
[ Parent ]

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#43)
by duden (mprism@ntlworld.com) on Fri Dec 29th, 2006 at 04:50:08 AM MST
(User Info) http://frenchstudio.co.uk

It's nearly a year since anyone posted about using disk-drive magnets so here goes.
First you can cut them with diamond tipped water cooled tile cutting machines available incredibly cheaply thanks to the Chinese!
Secondly, why not cut each magnet in two or even three equal parts and use them across the rotor (stacked with three or four others of course).
However often you cut each bar magnet you will still get a collection of N-S magnets which is not ideal.
Please come back with reports on progress with various experiments!

Re: Wind Generator with Hard Drive Magnets (3.00 / 0) (#44)
by ghurd on Fri Dec 29th, 2006 at 08:44:39 AM MST
(User Info)

You have a misunderstanding about disk drive magnets.

[ Parent ]

Wind Generator with Hard Drive Magnets | 44 comments (44 topical, 0 editorial)

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