requesting help choosing a motor

[ezee]

Hey all...I have reveiwed all the plans on the other power site, and downloaded hugh p.s pdf on building your own PMA.

My situation calls for a pretty small motor...bigger than a toy but much smaller than the large 500-1000W jobs you guys are putting up.  I want to use a permanent magnet motor, but WIEGHT is the biggest issue, it needs to be pretty portable.

So:

1.  Is there some common use for small perm magnet motors that I can use, like computer cooling fans or other common motor?  I guess I want it to be JUST strong enough to charge a single 12V battery.
   
2.  Or am I better off trying to design and build my own based on the plans available...just scaling down the size?
   
   

Thanks!

[Slingshot]

We need a little more information.  At what rate will you be using energy?  That's basically what drives the choice of turbine needed.  You must replace the energy at an average rate equal to or slightly greater than you use it, and the battery must be large enough to cover the periods when you are using but no charging is available.

[luv2weld]

Without more info, try this one.

http://www.velacreations.com/chispito.html

It's made from a treadmill motor. Search otherpower archives for other articles about

treadmill motors.

Ralph

[ezee]

I'm sorry...thanks for the guidance.

It's for a proof of concept backpack windmill....so basically the question is "how much wind power can I generate under 50 lbs total weight"

The tower, turbine, etc must all weigh less than 50 lbs total  I envision blades made from fabric with light plastic ribs (like tent pole material) with battens like a sailboat sail.  The tower might be nested pvc, etc.  Maybe even a kite

Has this been done before?  

Basically, a small DC motor is too small and won't have enough power.  An automobile alternator or home-built PMA like what is on the otherpower website is too big.

I need something in between...like (Im guessing here!)  100W?

would any of these model airplane electric motors work?

http://www.rctoys.com/rc-products-catalog/RC-PARTS-BRUSHLESS-MOTORS.html

Thanks!

[ezee]

Thanks...do you think the rc plane motors would work also...they seem to be lighter and just as available as the treadmill motors

(I saw that btw...the velacreations site, very clear and easy to follow, I love that site)

[luv2weld]

I don't have any experience with the RC motors. But if they are permanent magnet

motors, then they should work. Just won't have any idea about the output until

you buy one and experiment with it.

[CmeBREW]

Sounds like a very interesting project. From my own humble experimentations, all those little 12v DC HIGH RPM permanent magnet motors don't generate high enough voltage to even begin charging a 12volt battery.(Most only generate around 3 or 4 volts @600rpm / 6 or 7 volts@ 1000rpm) Those simply are not close enough. However,  I've never tried hooking 3 of them in series though???.

On the other hand though, what came to my mind was the Dynohub generators that Ben makes.

You might try talking to Ben at:

http://www.gotwind.org/

Those neat light weight Dyno-hubs (for bicicle headlights) might be what you're looking for. They reach 12volts easy at a very good low rpm ---which means you could maybe try a 5 foot rotor to overcome cogging. Two pine blades carved at a 10 degree angle slope would be very light weight. And to make them where they can assemble and disassemble from the hub would be really cool. A couple of those dynohub generators could be great for efficiency lighting and even one of those 10 watt 10 inch Television. Sounds like alotta fun.

I almost wish I had a nice place to hike and camp in the wilderness!!

[pigpen]

Here is another sight that might help http://www.mdpub.com/Wind_Turbine/index.html  He uses a ametek motor he got of Ebay

[Tritium]

How about the MiniGen on this page.

http://www.windstuffnow.com/main/minigen.htm

Thurmond

[ghurd]

Something here may help.

http://www.fieldlines.com/story/2005/8/30/93127/7953

G-

[luv2weld]

ezee,

earlier you said "It's for a proof of concept backpack windmill....so basically the question is "how much wind power can I generate under 50 lbs total weight"

So is this something you are trying to invent??? Or sell commercially?

Why are you trying to "prove the idea"?

Ralph

[ezee]

I just want to see if it can be done, I have no aspirations to invent anything, even if I accidentally do so in the process.

I have been following the DIY wind power web sites for some time....and It just kind of dawned on me that most of the projects are either REALLY small demo type experiment kits...or REALLY big turbines meant to run a house or a cabin.

For my first project...I want to build something bigger than a toy , but small enough so that it doesn't cost a lot, require special machining, and hopefully that I can take with me.

I'd like to take it with me to the park or the beach to use to charge a small laptop while I work....this is why I want it to be portable.  Also...since I have never seen one like this, and I have a background in sailboats...I thought I could make a wind generator using construction techniques used to build the plane below:

http://www.hobby-lobby.com/cobweb2.htm

I know that turbine blades built like that wont have enough ass to push one of hugh's homebrew PMAs....so I'm asking what I should use as a motor for this project.

[ezee]

YES YES YES  bullseye!

Could this charge a small laptop battery?

This is what I am looking for...size wise that is.

[luv2weld]

Man you must have good self control!! I couldn't even pretend to be working at

the beach. I'd be drooling all over the keyboard. Guess that's why I live in

the woods. People don't know how to react when they see someone wild-eyed

and drooling all the time!!!:)

Ralph

[ezee]

So I think I am on the right track.

The minigen is where I am starting, the one found here:

http://www.windstuffnow.com/main/minigen.htm

I'm in the process of ordering that now, waiting on an email response from elenz

If that doesn't prove to be what I'm looking for, then I think a more modern version of some of Ben's designs might prove worth looking into.

He uses older bicycle hub generators and sidewall friction generators...but they now make much newer and more efficient versions of both.  They even sell a 12V version that looks VERY promising.

Ill keep ya posted.

[ezee]

just got confirmation...my minigen is ON THE WAY!

[Slingshot]

Assuming you want to put this together quickly, with a minimum of self-building, you can do what you're looking for with one of the 7-inch DC servomotors (Ametek, Lamb Electric, etc).  The motor will weigh about 10 lbs.  For light weight and simplicity, buy a set of the black pre-made "hornet" blades from hydrogenappliances.com.  If you're resourceful, you can probably come up with a 10-foot collapsible guyed pole made from aluminum tubing.  Or, just build the upper stub section and plan on improvising a lower guyed pole from "found" materials at your campsite.  Design this as a "downwind" turbine so that you don't have to use a tail to keep it aligned with the wind.  

This arrangement will give you close to 100 watts if the wind is cooperative.  I did a similar thing with Ametek motors about 15 years ago - it was for extended camping trips at a lake shore, where there were usually good winds due to thermal activity.  I would just set the unit up on the shore, and it would keep my boat's trolling-motor battery topped off and provide us with radio and lights for the campsite.

In order to stay under your 50-lb limit, you will probably not be able to carry enough batteries to deal with 100 watts on a hard-wired continual basis, so plan on a lightweight controller of some sort.

For less money, you can also use one of the $20 "treadmill" motors available all over the internet.  Do a Google search for "Chispito" to see an example of a unit built with one of these.  The treadmill motor bearings and shaft are not quite as sturdy, but then the motor may weigh a little less also.