Wondering what the smallest sized single and Dual rotor

[coldspot]

Well,

I'm thinking about a crazy idea I came up with

and this leads me to researching about voltage and watts from a very small sized single and or dual rotor gen. Small being about 2"-3" rotor/s !

Any links would be helpful, THANKS!

This won't be wind driven or at very high RPM or needing to make very much power, (I hope that is as testing stuff and variuos things is still underway)

I have a bunch,(200) of half inch by 1/8" neo disc magnets to use up and am trying to come up with a way to use them on this one.

I can't really give out very much info about the end use of this as I hope to be able to get a "real product" made in the end and would like to make a little if not a lot of money from the idea. (At the very minimun at least a couple of working units,[4-6], as this was a dual person dream-up idea, me and girlfriends brother, {person letting me build little shed/shop for working in at his place}).

 I know that without very much info help would be limited and understand that but, all that I need isn't that much help anyway. Just trying to get a bit of legwork done at this point about what can be gotten from very small stuff, as I have played with some small DC motors and small steppers but this will have to be more like a single rotor type of a unit unless I come up a way to make it a dual rotor one.

 Right now I'm going to do a little bit of testing using a bike headlight rub on wheel type of little gen being hand cranked, (6 volt unit I think, might go buy a 12 volt one also, could use new one on mnt. bike anyway)

So please link me to any stories or other anything that can be of help with this micro power stuff.

THANKS

[willib]

i may have the record for the smallest alternator , the MinigenI .

http://www.fieldlines.com/story/2006/4/8/24913/42356

i think i was testing the 7/8" dia mags at the time , but settled on 1/2" dia by 1/2" mags ,

there are probably newer photos of the present blades , the smallest ones , in my diaries somewhere.

its hard to believe , i was still using those pitifull blades as recently as april of last year..

anyway i still have the minigen I,

i could have squeeked a lower cutin , by using thinner wire , if i had ,had any.

i clocked the present blades at about 900 rpm in a stiff breeze.

[coldspot]

willib-

Thank you !

I thought that either you or jerry would have done the smallest one yet.

So-

 It got 2.29V dc @ 361 rpm with three  9 3/8  inch radius blades.

Then i hooked it up to a 1.2v NiMH battery.

it was putting 115 mA into the battery @ 263 rpm

thats 138mW"

Then that ='s, 2.3V DC, 115mA being 138mW @ 361RPM's

With a 4.25"dia dual rotor machine

Using 8 poles, six coils. with 130 turns of #20 gauge

mags are 7/8" dia x 1/2 ".

Again Thank you !

Well, I won't have any blades as it will not be wind driven and don't think that it'll get up to that high of RPM"s either.

(I must get out the old model airplane Tach and do some testing to get a feel for the RPM's available)!

Without doing the math, just looking, I have a little metal rotor type plate that has 6 magnets 1/2" Dia. spaced around it with about a 1/4" space between each. That isn't going to work out to be an easy coil number for 3 phase. maybe it'll hold 7 magnets? Or would just 5 be better to only use 3 coils?

 

[willib]

what dia is the plate?

[ghurd]

Watch out for too small.

Small magnets means more turns.

More turns means less space in the center.

There is never enough space in the center.  At least for me. :-(

G-

[coldspot]

OOP's

(thought I had posted that info)

this little plate with a shaft out the other side is

about 2-1/8" dia.

But this isn't any part of what I'm trying to build.

just something close that I had already put some magnets on long ago, (was maybe trying to spin it next to a copper tube with water inside). lol

Little micro size gen I'm trying to build would be around 2" to maybe 3" dia and might have to end up being only a single rotor.

But,

Only needs to make enough power to heat up a couple very small elements, very small!

Do LED's heat up?

I just got a "CEN_TECH" #93983 Non-Contact Infrared Thermometer a couple days back and need to start some testing !!!!!!!!

[wooferhound]

the smallest ones that I can think of are the Box Fan Conversions about 4 inches in diameter. I made one but the results were'nt very good

http://www.fieldlines.com/story/2003/12/30/143548/79

Others have made them with better output

[stop4stuff]

Here's a few of mine;

Weight Driven Generator - http://www.fieldlines.com/story/2005/11/10/191155/99

Dual rotor, 2" diameter, 6 pole (12 mags) 10mm x 3mm, 240rpm (ish) output = mW

16,200 rpm Lego alternator - http://www.fieldlines.com/story/2004/5/18/7432/22805

Dual rotor, 1.25" diameter, 2 pole (4 mags) 5mm x 5mm, 16,200 rpm ouput = nowt, this was a demsonstration of rpm capablities of Lego construction

Hand driven generator built with Lego

http://www.fieldlines.com/story/2004/5/13/05243/2453

http://www.fieldlines.com/story/2004/5/26/15451/3307

Dual Rotor, 2" diameter, 6 pole (12 mags per rotor doubled up), 3500 rpm, max output 3W

Paul

(bought to you today by DinoDialup @ 32.1kb)

[coldspot]

Paul-

oop's, I'd forgotten about you when I posted that

willib or jerry would have been the one who made the smallest sized so far.

YOU WIN !!!!!!!!!!

And after reading your posts, (rereading that is),

we are about on the same page as to size and whats being used to drive the gen's, "Hand cranked"!

Thank You!

The info you have posted will be of help and thats what I asked for, but this still has a ways to go and with only close to normal people as far as time to spend on it, I'll be working for many more days or weeks before I see anything close to a working test bed.

The use of "Leggo's" was a good idea and seems to have worked great for you. But, what I'm doing and  the fact that we bolth are using gearing up in our stuff. Makes me think I may have had a better idea as a testing bed than you did, but I can't tell you any more than that, yet. But I'm also sure you and everybody else here or not here has at least one or more of these at home and only needed top have the same crazy in the head thoughts people like us have to have seen the light and tried this themselfs.

PS: Paul, I love your user name!

I have even been telling people that myself, when anybody calls me a "Dumpster Diver", I tell them "NO I'm NOT", I'm more like a "stop4stuff" type of person!

THANK YOU!

Have a Great Day/Night!!!!!!!!!!!!!!!!!!

 

[willib]

stop4stuff has me beat with the 2"dia dual rotor.

just remeasured the rotors on minigenI

4" dia , 24 of 1/2" dia by 1/2" thick ,12 per rotor neos, but the mags arent out to the edge , so you could get by with a 3.5"dia rotor

i could have increased the voltage output ,

by winding the coils with a smaller hole ,more turns..

and using smaller dia wire , also more turns , i used 0.034"dia (#20) wire.

as it is it makes a nice rechargable battery charger, (NiMH batteries.)

the coils are 1" dia , by .48 thick with a 0.48" hole.

if i had used a 1/4" hole ( the distance between mags)i could have increased the output, but at the time i just wanted to get it done.and i had the coils allready wound from another project.

on a side note , i cut the rotors out of 4"square electrical box plates

and mounted them on the HD bearing in the picture.

[nothing to lose]

 Not knowing anything about what your doing I'll just mention that those twinkle lights get hot. $1 for a string of 35 Christmas lights.

 Low volt low watt heaters?

Just in case the Leds don't work out.

[coldspot]

ntl-

"twinkle lights"

Any info or idea as to what they require as to

volts

or

current

to drive them?

I don't have to play with or test

(girlfriend wouldn't like it if I touched hers)

Will keep my eyes on the lookout for some.

Thanks

[nothing to lose]

 The strings vary and the volts for the twinkle lights vary also. Normally I think 1.5-3V. I used to mess with them allot but it's been awhile. I think the superbrights are 3V. The other normal ones I think are 2V but work on 1.5V I think.

 As far as amps, I don't know. Can't be much, I have ran them for fairly long periods on AA,C,D batteries in the past. I've ran them on 12V but right now can't remember how many I ran in series to do it.

 I should have a bunch around here, but this time of year they will be burried agian somewhere already, I have limited space now and everything is burried under something.

I'll try to find some and test them within a few days, if you need some I might be able to send you a dozen or more free since now they may be hard to find in stores also.

E-mail me if you want, though I have not been online allot recently but I will answer when I am. If you want when I find them I can also try to test the temps with the Non-contact thermometer.

 I should also start testing them for some of my own projects needing minor heating.

Being low volts like they are I can wire any number in series for almost any volts I want. When one burns out the rest stay lit (but burn at a higher volt ) so the entire string does not go off. The really old ones if one went out they all went out, but anything in the last few years (maybe 5-10) should not do that.

I was going to build a small Egg incubator soon and lots of these twinkle lights on  some 19.2V battery packs may be just right

Anyone wanting to play with these, watch the Thrift stores, they get allot of them often and sell then cheap normally. May want to ask for them if you don't see any, they may have some but mostly put them out around the holidays.

[coldspot]

ntl-

Thank You !!!

You are very generous with your offer !!!

I should be able to find some locally, (if not I'll raid girlfriends stash, lol).

I did find a single bulb while working the other day but, it didn't last long enough to get a temp reading from when driven by 12 VDC bike gen spun with hand. Should have used 6 V one or less but didn't know what voltage they are at.

a LED I tested didn't show any temp increase but, being that it was a 12 V DC ready version, the heat was probably in the resistor under the heat shrink.

Are you up to stock on any # 29's yet?