Author Topic: 30" stator (Read 3709 times)

harrie · « **on:** August 17, 2006, 03:41:54 AM »

This is a 18 coil stator, two in hand #15 mag wire with 75 wraps. The stator will be 5/8" thick. I used a combination of 3/4 MDF, and 5/8 " plywood. I use melted toilet bowl wax brushed on for the release. I think if I did it again, I would use melted candle wax, because it sets up harder, and would not become imbeded in the bottom layer of fiberglass cloth. the first picture is the 1st phase of 6 coils in place.

This is the way the conections were made, using 1/8"copper tubing, shrink wrap,and sodered. I think Dan or someone came up with this method, which works very good.

This shows all three phases in place, and oh yes, I used plywood blocks the shape of the inside hole of the coils which I think is good for two reasons, to help cool the coils, and also more important to keep all the coils in exactly the place I want them to stay, due to haveing to remove and replace during the pouring operation.

Close up of the star delta conection, using brass screws drilled for the wires, and sodered.

Here I used some of the waste plywood from the stator form, and wired it to the plastic ties that are around each of the coils, so that the whole unit can be easily picked up and put aside while installing the bottom cloth, and put back in. I put the coils in prior to pouring the resin. I than poured in about half of the form, and used the plywood ring to lift the coils alowing the resin to flow under, and than removed the plywood ring, and completed the pour.

This just shows the coils removed from the form.

Bottom fiberglass cloth in form.

The rest of the operation is pretty typical with what has been shown on this site, so no need to show anymore, The stator removed from the form very easy, and was satisfactory in my mind, of course with a few small bubbles.Any comments or questions appriciated. Harrie

harrie · « **Reply #1 on:** August 16, 2006, 09:49:04 PM »

Sorry about picture #3, not the one that should be there, Guess I should have reviewed first.

Shadow · « **Reply #2 on:** August 16, 2006, 10:29:40 PM »

Wow! I'll be the first to say very nice work! But 30 inches!!? thats almost 3 feet! What size blades are we talking here? You've got some good ideas/methods that I'll be using on my next one. Thanks for posting!

willib · « **Reply #3 on:** August 16, 2006, 11:52:34 PM »

Nice work as usual Harrie

i have a question although not particulary geard to you

Why are you still using plywood ?

with the availability of plastic ,why is anyone still using plywood ?

below shows the kind of finish that plastic can give , i put the completed sheet of fiberglass over my pocketknife to show the finish.

it just peeled off and did not stick at all.

the plastic is about 7/16" thick , i found it , so i'm not sure of the type of plastic, Polyethylene maybe.

another shot of the finish , look at the gloss !

there is no reason to expect that a solid stator would come out any different..once its done just peel or pry it off the plastic .

one problem i see is if the stator gets too hot it may warp the plastic , but if it is bolted in the middle and at the perimeter it should hold up well

maker of toys · « **Reply #4 on:** August 17, 2006, 12:05:53 AM »

Mmmm. . . a glossy surface might not be ideal for radiating heat. Might have an advantage if you were trying to couple the heat conductively to a heatsink. . .

and a rough surface has more surface area, better for convective heat transfer. Too, the rough surface encourages turbulence and should improve heat transfer by directly involving more of the flow. (though with a rotor skimming by at a pretty good linear rate, that's probably a moot concern. <G> )

Hmmm; maybe a smooth surface would reduce magnet heating? Experiments. . . . too many experiments I want to make.)

Smooth sure looks good, though.

-Dan

willib · « **Reply #5 on:** August 17, 2006, 12:46:29 AM »

Almost forgot , AWESOME !!

absolutely awesome..

did you weigh the stator?

length and width of the coils?

size magnets ?

rotor dia?

i've allways been partial to 18 coils & 24 poles

but wow

what size blades are ya gonna put on this beast

paradigmdesign · « **Reply #6 on:** August 17, 2006, 06:47:36 AM »

My guess would be 12 to 13 foot radius.

disaray1 · « **Reply #7 on:** August 17, 2006, 07:02:15 AM »

I think that plastic willib is using is called King Starboard...a marine polymer, also some call it "Sea Teak". Cool stuff. You can get it smooth, or with a anti-skid (if you were looking for surface area cooling). I haven't found much of anything that sticks to it. Thickness up to 1". Works well with wood working tools. Can be bent and welded! Kind of expensive though.

30 incher! Wow! Nice work. That would make one helluva bicycle gen. Where's Lance Armstrong?

disaray1

jlt · « **Reply #8 on:** August 17, 2006, 07:20:02 AM »

It looks great harrie. on the 16 inch that i am working on i used candle wax and melted it into the wood with a small hot iron and a propane torch and it worked out very well. when i turned the mold over the stator fell right out.also when making the coils i took a coil and put wax paper under it . then i poured some resin about 2 table spoons with 20 drops hardner in it more wax paper and then a metal plate on top and then clamped it for about 5 min . I iam looking forward to hearing more about yours what is the size of your mags.

harrie · « **Reply #9 on:** August 17, 2006, 12:01:55 PM »

Hi Willib, The stator weighs in at exatly 32lbs, coils are about 4 inches wide, and 5 inches high. Mags are the 2 inch X 1/2 disc mags N38.Space between mags is close to 7/8", and the rotors will be 24&3/4 dia. 1/2 " plate. Im going for very slow RPM, 48 volt, with a 26' Dia blades. and yes, 48 mags total

harrie · « **Reply #10 on:** August 17, 2006, 12:14:32 PM »

Hi shadow, thanks for the comment. Yes its going to be a big one, Im kinda planing and building as I go, Im trying to do the same thing I did with the 18 foot, which is to keep it at a very low RPM, so that it will remain in stall in all winds. Im not planing on any furling. I know the available power will not be realized this way, but Im looking for continous amps even if they are low. The 18 foot, now that I have had it up for 4 months, is always puting out power, in very low winds. If it is turning, it is putting out power. Im thinking it may have something to do with the dia. of the blades and also the weight of them?" Im not smart enough to figure out all the formulas, so build off the seat of my pants, Ha. I will post more about it later.

greatt fun harrie

harrie · « **Reply #11 on:** August 17, 2006, 12:18:13 PM »

Hi jlt, good to hear the wax worked out, never thought about using a hot Iron, Thanks for the repley

harrie · « **Reply #12 on:** August 17, 2006, 12:34:15 PM »

Oh ya Shadow, I forgot to tell everyone that if your looking for the hole in the center of the coils, by using the form blocks, I made sure I had them well covered with vasolene along with the wax. I also covered the inside of the coils with vasolene. I did have to remove the top layer of fiberglass, using a dremel tool (very carefully of course), the inside of the coils cleaned up very good, all bare wire showing.I think how much this helps for cooling is anybodys guess, but I would think it would help.

picmacmillan · « **Reply #13 on:** August 17, 2006, 12:58:25 PM »

hi harrie...great job.....i havent been able to be on in a while, and i think the last time we spoke, we were both building dans 17 footer....hats off to you my friend on your project...looks fantastic and i am proud of you..if one thing i have concern with is the heat created in the stator...danb told me the heat in our 17 foot stator can get to over 400 degrees farenheit?...not sure , but maybe give him a buzz to see what he think of the heat that can be generated, and how we might heat sink it or absorb it

...great, great loking job ...pickster

harrie · « **Reply #14 on:** August 17, 2006, 02:57:11 PM »

Hi picter, must be busy building the log homes huh??. As far as the overheated stator, I wont have that problem, due to keeping things in low RPM. Im hopeing to keep it below 20 Amps in all winds, due to stalling. Like My 18 foot, if I think I need more, I can always switch to delta, which will allow the blades to turn faster. My 18 foot puts out a pretty steady 2 to 7 amps all the time. I switched that one to delta, and it than put out 20 amps in about a 7 mile wind. Like I said before, IM not off the grid, and only use the power for some things in the house, and of course its nice to have it for emergencys. I guess its more of a hobby for me.

Thanks for the comment, Harrie

Ungrounded Lightning Rod · « **Reply #15 on:** August 17, 2006, 03:40:07 PM »

danb told me the heat in our 17 foot stator can get to over 400 degrees farenheit?...not sure , but maybe give him a buzz to see what he think of the heat that can be generated, and how we might heat sink it or absorb it

Thinking about all that heat and trying to dump it makes me wonder about water cooling - and using it to heat the house water and maybe the house. B-)

(You'd have to keep your water pressure in PSI somewhat over tower height in feet / 2 to keep it from sucking air through any pinhole leaks.)

(Too bad winding the mill with thin copper pipe would greatly boost eddy currents and thus the fraction of the power that went into heat.)

willib · « **Reply #16 on:** August 17, 2006, 04:50:48 PM »

Harrie in the pic below is the distance fron the right side of hole 1A to the left side of hole 2B , two inches ?

I also think the hollow coil hole is a very workable plan

Ungrounded Lightning Rod · « **Reply #17 on:** August 17, 2006, 06:39:56 PM »

Love the bit with lifting the coils slightly after the first half of the pour to get a thin coat on the far side.

harrie · « **Reply #18 on:** August 17, 2006, 07:54:23 PM »

No willib, its 2 & 3/4 inchs, I think it depends on the spacing of the mags, when mag #1 is centered over coil #1, the right side of the next mag, would be just approching the center of coil #2, the next mag would be exactly between coil #2 and coil #3, and the left side of mag#4 would be at the center of coil #3. hope this makes sence, Harrie

powerbuoy · « **Reply #19 on:** August 17, 2006, 08:18:12 PM »

Looks very impressive .... What voltage do you receive in a 7 mile wind at 20A?

Powerbuoy

willib · « **Reply #20 on:** August 17, 2006, 09:48:51 PM »

"If it is turning, it is putting out power."

i like that

slow and steady

DanB · « **Reply #21 on:** August 18, 2006, 07:28:56 AM »

to clarify that... if figure my 17' machine must've got over 400 deg when it burned up last winter - that would hopefully not happen again!

What voltage are you running at Harrie?

DanB · « **Reply #22 on:** August 18, 2006, 07:40:35 AM »

Hi Harrie - why not have this furl? It might be quite scary if the blade overpowers the alternator. If it were me I would downsize your blade from 26' diameter. I may be off here but I'm guessing you'll get 48V cutin around 60 rpm, which is not slow at all for a 26' blade and the resistance is high enough I think such a blade will easily run away on you. You'll know more I suppose when you test it.

harrie · « **Reply #23 on:** August 18, 2006, 09:05:50 AM »

Hi dan, yes you are probley right, I guess I can always cut some off the tips if that is the case, Im planing on puting a slow RPM high tourqe motor on the yaw pipe that will turn it out of high winds. I did have room for more wraps of wire, so maybe should have did that also, like you said, we will see.

kitno455 · « **Reply #24 on:** August 18, 2006, 02:13:51 PM »

he's in rehab

allan

harrie · « **Reply #25 on:** August 18, 2006, 07:03:54 PM »

powerbuoy, I origenally built the 18 foot for 48 volts, but cut in was too high, so left it at 12 volt for awhile, and decided I was happy to see it just sit there and lug at 40 RPM, and put out a average of 4 amps even in very low winds. In fact, sometimes the wind is so low that it will not yaw into it, but if I climb the tower and turn it into the wind, it will take off and again I see from 2 to 7 amps. On this big one, I plan on making sure I have good yaw bearings that will turn the turbine very easy. Im getting too old to keep climbing. ha

hitech70 · « **Reply #26 on:** August 25, 2006, 08:43:44 AM »

wao it is a big stator but what is the power output?

harrie · « **Reply #27 on:** August 27, 2006, 08:27:40 PM »

Well, that is kind of hard to answer, The power output depends on The RPM in any given wind speed, and of course the magnet size, and air Gap between the rotors. My plan is to charge a 48 volt battery bank, and keep the turbine at a low RPM chargeing at a rate of 20 amps max. Im sure that wild AC, could reach over 300 volts if allowed to run unloaded.

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Author Topic: 30" stator (Read 3709 times)