Author Topic: mini-gen done! (Read 2239 times)

willib · « **Reply #1 on:** April 17, 2006, 02:15:31 PM »

This gen has 12 poles 9 coils and was really fun to make.

the magnets are 1/2"dia x 1/2".

coil data::

04-08-06 Program input Gauge= 20 Wire dia. = 0.0340 inches ohms per foot 0.0101500

coil od = 1.000 coil width = 0.480 coilid= 0.450

Program output:

Final Diameter = 0.994

coil radius = 0.275

Num turns per coil radius = 8.088

Number of turns per coil width = 14.118

total number of turns 114.187

wire length(feet)= 22.167

Single wound ohms per coil 0.224996 ohms

Total ohms for one phase (3 coils) 0.675 ohms

Delta single wound line to line resistance (2 coils / phase) 0.3000 ohms

above i was tweaking the blades for maximum rpm .

i got 327 rpm with the fan on high.strangely i got 308 rpm with the fan on low.

on the scope is a snapshot of the phase voltage ,set on 1V / div and 0.005mS / div.

the blades are 9 3/8 " from center to tip.

i plan on using this gen to charge 1.2 V NiMH rechargable batteries.

more on that later

willib · « **Reply #2 on:** April 17, 2006, 02:32:49 PM »

sorry i ment to type 5mS / div.

also the delta line to line resistance is for two coils not three, i hadnt changed it since when i was going to put two coils per phase on the mini gen..

willib · « **Reply #3 on:** April 17, 2006, 03:54:04 PM »

also the stator is assembled not cast

after i made the fiberglass sheets , i placed the coils over a template, and used resin to secure them in place , then i put the top piece on and used resin again,

its a very rigid stator, with very little resin used..

behoof · « **Reply #4 on:** April 17, 2006, 04:59:15 PM »

That is sooooo cool just simply awsome... what a neet project and thus that ol' statement... form WITH function

Thanks for the peek,

behoof

gator · « **Reply #5 on:** April 17, 2006, 05:44:37 PM »

Very, very cool! I wish this stuff wasn't so far over my head. I keep reading though and slowly getting supplies to start my wind gen. Nice little project. Keep sharing!

harrie · « **Reply #6 on:** April 17, 2006, 08:53:47 PM »

Hi Willib. Now that is a neat looking little turbine, I know even something that small takes a lot of work. Thanks for shareing, Harrie

willib · « **Reply #7 on:** April 17, 2006, 10:22:38 PM »

Many many thanks to all on this site without yous guys i dont think i could have finished it.

Below is the minigen charging a 1.2V battery. During this burst of wind it hit 80mA and ive seen it as high as 220mA.

i dont know where this wind ,but i'm ready for it..

wow it just hit 316 mA.

willib · « **Reply #8 on:** April 18, 2006, 07:12:06 PM »

I've graphed the data point i got last night

this is the data

(mA) RPM - fan speed

89 - 222 - low

121 - 240 - med

150 - 256 - high

these three points i got charging a 1.2V battery by the fan method.

this last point i got last night was 316mA and i plotted it to fit the curve.

http://www.otherpower.com/images/scimages/2965/line_3BDFB1B4.jpeg

ghurd · « **Reply #9 on:** April 19, 2006, 01:11:42 AM »

SOoo off topic for this thread

I'm working in from reverse. Keep getting 140-ish turns per coil.

What do you come up with for this...

Dual 8/6, 3/4 square x 5/16" N45 neos, #20 wire, 1 meter blades, 5.5 TSR, 5.5MPH cut-in.

Rotors look like they will be 4.7" max.

G-

willib · « **Reply #10 on:** April 19, 2006, 02:10:09 AM »

still on the drawing board?

what i mean is you dont have any test coil data?

ghurd · « **Reply #11 on:** April 19, 2006, 10:21:07 AM »

No test coil. I'm pretty sure 140 per coil will get me in the right area.

Wondering how big the disks should be before I start in ruining the nice 4.75" speaker plates.

And if 140 turns of #20 per coil will fit with the stator 1/2" thick, given the 4.75" magnet disks.

Breaks my heart everytime I waste 2 pounds of wire, even worse when I ruin something like those rare speaker plates. :/

G-

willib · « **Reply #12 on:** April 19, 2006, 11:56:08 AM »

Those speaker plates are thick? enough to hold the neos on tightly?

the reason i ask is,there is a chance you could use 3 coils per phase IF, you dont mind the mags sticking off the end of the rotors a little bit?

like 0.152" ??

ghurd · « **Reply #13 on:** April 19, 2006, 12:29:22 PM »

The plates are about 1/4" thick.

The 0.152" overhang is with 12 magnets? Seems like that would be kind of close.

willib · « **Reply #14 on:** April 19, 2006, 12:50:12 PM »

"The 0.152" overhang is with 12 magnets?"

yes.

if you havnt bought the mags yet consider round ones ,

the distance between mags with 12 round neos centered on 04.304"dia is 0.378"

the distance between 12 square neos is 0.190" on the inside edge ,same dia.

http://www.otherpower.com/images/scimages/2965/ghurds_rotors_and_coils.JPG

ghurd · « **Reply #15 on:** April 20, 2006, 05:08:18 AM »

Thanks!

Had these mags a long time.

G-

willib · « **Reply #16 on:** April 20, 2006, 08:59:15 PM »

On these blades , when the hub loosens up , or the wind is really strong , the blades trailing edge tends to move forward , (into the wind) ,which way should i move the pivot point ,(mount) and more importantly why.

(you must justify your anwser)

ghurd · « **Reply #17 on:** April 21, 2006, 07:19:50 AM »

Flatter? Because the blades are trying to go faster to the point where air resistance is forcing them to a lower angle of attack?

I don't know, but its interesting that happens.

G-

willib · « **Reply #18 on:** April 24, 2006, 02:24:37 AM »

Yes , i thought so..

willib · « **Reply #19 on:** April 25, 2006, 01:34:08 PM »

i was testing the minigen , and got 1A DC from it , turning it by hand @ 250rpm.

just need a bigger set of blades for it i suppose .

no problem there.

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Author Topic: mini-gen done! (Read 2239 times)