Magnets for home built alternators

[crafty2002]

I am trying to learn how to build an alternator from scratch and see a lot about different types of magnets.
The magnets I really want to try is way out of my price range but I have been wondering about something else. I see now that you can use just about any number of magnets as long as it is an even number. I know the stronger the magnet the more power you can produce but as magnets go, that are designed for this, the bigger, the better, the more they cost.
I have used welding magnets for years that are designed to hold metal together while you get it tacked in place.
Some of those magnets are about equal in pulling power as a $30 magnet is that is designed just for alternators.
I have 2 large ones, I think they are 6" ones, that is something else to get to turn loose and that is with it on the edges. I can't get them loose if they are layed flat. I must work it around and get it up on the edge first.
I am wondering a few things here that I haven't been able to find out so far.
The main thing is can you cut a magnet without destroying *it. I know you will loose some of the power because of reducing the size but I am wondering about the cutting itself!!
Harbor Frieght has some 4 1/2" welders magnets for sale for $ .97 each. I can cut a wedge about 3" wide at top and 2" at the bottom and about 3" long out of them.
And for the cost I could put as many of them in an alternator as I cared to.
Does anyone have any suggestions on this. Good??? Bad??? Whatever??? *
I am still trying to get a grip on how to build one.

[kawalekm]

Hi Crafty

I surfed up a wind generator site before that used the magnets recycled from dead microwave units. Here is the site that describes specifically how to make an alternator from your own magnets.

http://www.scoraigwind.com/

Here's a page where the guy mentions cutting the magnets to the size he desired.
http://www.greeleynet.com/~cmorrison/magnets.html

Here's a great page that has lots of wind links
http://www.builditsolar.com/Projects/Wind/wind.htm

Good luck,
Michael

[bee_pipes]

Also check out
http://www.otherpower.com/

You'll find all the info you need, and they sell some bull magnets to boot.

Regards,
Pat

[chrisser]

Will breaking a magnet damage it?

Just thinking about how cracked connecting rods are made. The big end is apparently forged and machined, and then the cap is broken off. I haven't seen one, but I imagine its a pretty clean break.

Not sure if you could rig up something to duplicate this. I know many magnets are brittle.

I wonder if its the actual cutting that damages the magnet, or the heat from the tool. Perhaps something like a wetsaw used for tile cutting (rent at Home Depot, for example). That actually grinds and is water cooled.

I don't know anything about this, but I'm just throwing out ideas...

[MadTripper]

I ordered some neodymium magnets from http://www.amazingmagnets.com a while back that are very strong and the prices were reasonable. *You can also find this type of magnet in old hard drives.

Tripper

[crafty2002]

Thanks for the replys all. I have found some of them but couldn't find them again until I hit your links.
Plus this was the first time I have been able to get the video of the steam engine powered alternator to worl. That thing is cool as it can be.
And he said they used an 18" disc for that one like they do for the 17' wind mills. I have also found out that with larger disc you make the "juice" at a lower RPM.
It seems to me that what everyone claims about water wheels haveing to be geared up so much just lost it's backing.
I read somewhere if you double the number of magnets and the size of the rotor they will make the same power at half the RPM's.
That steam generator made 2 KW's at 200 wat's with an 18" rotor, and it used 1 1/2 x 3" x 3/4" magnets.
With the magnets I want to cut and use, "IF" and I do say if, I am right with my math, my magnets will be about 65% larger than what he used. So I can make the coils larger so even with the cheap magnets I should be able to get at least as much power each time a pair of magnets passes each coil.
It will take me a lot more wire and that isn't cheap either but the wire shouldn't heat up as much. Again, "IF" I am correct here.
According to what I read if I were to build a pair of rotors 72" in diameter, it would only need to turn 50 RPM's to = the 200 for the 18" rotor. And if I build a 22' water wheel with the rope drive going to a 12" pulley on the alternator shaft, the wheel would only need to tuurn about 2.25 RPM's to have the magnets passing the coils as fast as the steam engine generator he has on the video. That would work out about perfect for a water wheel. If it turns faster it will make even more power.
Since the alternator is the governor in this situation, if there isn't enough water flow to keep it running faster, it simply won't make as much power. It will turn when all the buckets are full, and that is one thing I am sure of.....
With full buckets the wheel will have about 50,000 Ft. Lbs. of torque on the shaft.
If the amount of flow is good enough which I feel like it will be, all it can do is turn faster and make more power.

If anyone sees anything wrong with what I am saying here, please tell me. This is just my way of thinking about it but I have been wrong before. I don't want to go through with this and come out looking like a fool.

And agin, does anyone know of a site or book that has charts that I can use to figure out how many turns of wire, the number, and the gauge I will need so I can figure that out????

Thanks again for the replies.
Dennis

[crafty2002]

I haven't gotten the answer I needed about the magnets yet. I did however, find a site that makes a rotor of magnets 28" in diameter that make it's power at 65 RPM.
But at the same time, I am the worlds worst for saveing anything on the computor and can't even find that again??? I guess I should wonder what makes me think I can build an alternator if I can't even keep up with sites. Well, for some stupid reason I think I can always just type in the same search words and find it. Most of the time it does work but it seems like every site I run across that I really like just doesn't come back up.
As for doing the building, I know I can, "IF" I can the the info for the magnets and the wire sizes and number of turns per coil.
I am getting close but I can't get an answer about the magnets.
I can buy the 4 *3/4" ( I said 4 *1/2" but that was incorrect ) now for $ .97 each. If I don't get them now they will be 3 or 4 times that by the time the next catalog comes out. *I am thinking that if I go ahead and buy 60 to 72 magnets now for less than a buck each I can build a rotor 42" - 48" in diameter and the rpm's will be really low to make the juice I want to produce.
I do understad the need to build it so the gap between magnets and coils stay at a set distance continuously. I have even worked as a millwright for a little over 2 years so I know what I will need to do to make it a precision machine. I am sure it will take a bit of time but being disabled, that is one thing I can handle. Millwright work for me was to lazy when I was doing it.
Dang, I hadn't thought about that. Maybe I need to look for a job as a millwright. Even disabled I could do that.
But for right now I just need to find out if these magent will work or not. I am sure they will, but how good.
If anyone knows anything about picking out magnets I sure could use the help.
Thanks
Dennis

[TheHebe]

Try some free cycle groups in your area or watch newspapers for school or business sales (office equipment) for old computers.

Your really wanting old hard drives out of the computers. The magnets your looking for are in the hard drives.

[machinemaker]

Another site for building alternators is www.windstuffnow.com a great site with some good links. Also every microwave oven has two ring shaped magnets. It you can find a appliance repair shop that might have some non functioning microwaves that you can haul away, salvage the magnets and other parts and take the rest to the scrap yard for cash.
kent

[crafty2002]

How strong are the magnets in a computor or microwave??
From what I have learned so far, the stronger the better. These welders magnets are strong as all get out when layed down on the flat side.
I am going to take one apart and see what it will pick up on a flat surface. I know they will pick up 50-70 lbs.
I have e-mailed several people that builds generators and no one has replied. ???
I guess I will go ahead and take a microwave and computor apart and check them too. I have one of each that needs going to the junk yard anyway.
Dennis

[JonSnow]

I have been researching vertical axis wind generators will little success as far as plans. I did come across this seller on Ebay that sells neodymium magnets and kits, blades and hubs for conventional wind generators.
If you find information on low RPM plans, please post them here.
Is there any one that has plans or info on vertical axis wind generators???

On Ebay>>>>Neodymium Magnet For Less

[randallhilton]

Another magnet purveyor:
http://www.kjmagnetics.com/

I don't know exactly what you need but these guys seem to have them all.

[sm0kin]

if i remember correctly intense vibration can cause a magnet to loose power. so if you plan to cut it with a saw or grinder then it could effect the power of the magnet. It has been awhile since i researched building alternators so i very well could be wrong.

[chrisser]

I have been researching vertical axis wind generators will little success as far as plans. I did come across this seller on Ebay that sells neodymium magnets and kits, blades and hubs for conventional wind generators.
If you find information on low RPM plans, please post them here.
Is there any one that has plans or info on vertical axis wind generators???

On Ebay>>>>Neodymium Magnet For Less

This is an old post, but this is a low RPM plans book that I think was worth the money

http://compkarori.com/dynamo/

I don't recall, but I imagine it could be converted to vertical axis with the right materials and some heavier thrust bearings. No real difference electrically, but the mechanical aspects of the design will vary a bit with the different forces acting on the parts.

Could also run it through a right-angle gear box and lose a bit of efficiency, but that could also be an opportunity to gear up or gear down the turbine to the generator if that was necessary.

[Curbie]

OtherPower's home built 2K generator:
http://www.otherpower.com/steamengine.shtml

Based on Hugh Piggott's work.

Curbie