Author Topic: 32in Radial alt (Read 5599 times)

vawtman · « **on:** April 16, 2007, 10:50:04 PM »

I was always thinking of building a big axial but shied away from that due the rotor and stator warping.

The little shiny object near the top is 1 1x2x1/2 mag.The wheel is 4in wide.

Wondering if i should make it an aircore or add another band of steel and make some sort of pole shoes.

Would be nice to have direct drive.

The tower is going to be taller and made of steel and would accomadate this gizmo.

Have a nice launchpad also.

Thanks

Axial alt

Pics seem a little blurry Sorry

Thanks

willib · « **Reply #1 on:** April 16, 2007, 05:13:33 PM »

i think it would work

is the perimeter of the wheel flat?

the pix look fine to me , very clear.

how much torque do ya get out of that setup?

does the wheel fit the shaft?

windstuffnow · « **Reply #2 on:** April 16, 2007, 05:30:54 PM »

I'd bet it would work just fine as long as the wheel ran fairly true. That's a big alternator!

Pretty slick set up you have there Vawtman! Have you ever measured torque off the shaft of your turbine?

.

vawtman · « **Reply #3 on:** April 16, 2007, 05:34:27 PM »

Yes this wheel is flat and i have another that is concaved a bit.

All i know torquewise is that i cant stop it with 2 hands on the shaft in moderate winds.Need to stick my hand out and bang on the blades.

Planned on beefing up the shaft and bearings,so yes.

Thanks

vawtman · « **Reply #4 on:** April 16, 2007, 06:03:31 PM »

Thanks Ed

Do you think it worth a try?I think the wife would make me quit smoking in order to buy all the mags(a good thing that ive been fightin)All i got so far is 48.

The wheel seems in perfect shape but havent spun it yet.

I did have the 5hp(4pl) conversion on it last fall and once it broke through the initial cog played with it but it was only running the motor at 300 rpms and the elements got pretty warm.

I remember you mentioning a spring scale method but never quit understood how to do it.

Would a air core be strong enough to hold it?

tecker · « **Reply #5 on:** April 16, 2007, 06:30:40 PM »

Should be able to stack alot of copper around that monster you'll want to have mags cover the 4" width in some configuration the suites your pocket book.

vawtman · « **Reply #6 on:** April 16, 2007, 08:03:12 PM »

Hi Teck

Would be able to run two mags per pole with the width.Thanks

tecker · « **Reply #7 on:** April 17, 2007, 02:53:28 AM »

Shure it looks like fun . 2" x 1/8 flat bar clamped to the flywheel will roll bend easy enough when you get it bent the spring back will give you an inch to stack coils on .Tack weld two together and your looking like a conversion . The cog won't be there if you leave it flat no doubt there will be some drag with the bearings and the metal backing but inertia should take care of that .

tecker · « **Reply #8 on:** April 17, 2007, 02:58:33 AM »

You could bump start the Alt by hitting a phase with 12 volts at a productive wind velocity

Stonebrain · « **Reply #9 on:** April 17, 2007, 06:12:58 AM »

Cool rotor,

What is the thickness of the outer rim.maybe it's enough.

It might be good to file flat surfaces for the magnets to make them stick better.whith that big diam,centrifugal forces can be important.

For mesuring torque you need some kind of brake.Maybe clamping the shaft between two lengths of wood and mesuring the force on the lever you have this way(just a thought).

How are the plans for the stator?

Keep it going

cheers,

stonebrain

Norm · « **Reply #10 on:** April 17, 2007, 06:34:10 AM »

Do you think it worth a try?I think the wife would make me quit smoking in order to buy all the mags(a good thing that ive been fightin)All i got so far is 48.

Want to quit smoking....take it from me...it's

easy friend, I started smoking when I was 12,

quit when I was 62, am now 75 I figure that I've

saved at least $20,000 (at an average of $5 a

day) If you want more support or details E-Mail

me. (user info)

( :>) Norm.

electrondady1 · « **Reply #11 on:** April 17, 2007, 06:47:56 AM »

i would think about 50 mags required vman.

just imagine, those loooong skinny over lapping coils.

about 100 of them i guess.

of course you need to go for it !!

but , to keep the wife on board

you may need to finish the dual rotor brake drum unit.

and the conversion too.!

ha ha !

looks like your yard is gonna be a very spinney spot!

electrondady1 · « **Reply #12 on:** April 17, 2007, 06:55:14 AM »

ps i used the "patch " this winter to stop smoking after 35 years

give it a shot. i feel a lot better.

TomW · « **Reply #13 on:** April 17, 2007, 07:09:50 AM »

vawtman;

I have a couple questions about the mount if you don't mind drifting off course a bit. Is that 2 railroad ties stuck in the ground for your posts? They look a bit smaller than ties.

Just curious if it is rigid enough for the forces? How deep are the posts in? I have been thinking of maybe trying a smallish what I think of as an H-vawt [H for horizontal]. That is a "typical" savonious type on a yaw bearing with the wind rotor horizontal. Just deep brain itch to try the design on the farm where I have lots of clear land for a half mile towards our normal wind direction. Thinking of a couple motor conversions as bearing and alternator in one part [think multitasker] on the ends of the drum. Don't hold your breathe tho I am slow to nearly stationary these days. This idea has been brewing deep in the dungeon of my skull for awhile . General idea being high voltage for ease of transmission combined with low and slow along the field boundaries about 8 feet up. If Ties work ok for the loading they are relatively cheap and easy to put up.

Personally, I can shoot so many holes in this H-Vawt idea it looks like swiss cheese but I still hope to give it a try. Put to rest those rumors that I am anti VAWT.

Cheers.

TomW

Flux · « **Reply #14 on:** April 17, 2007, 07:13:04 AM »

I agree that it would be a good idea to get some turbine performance before spending a fortune on magnets and copper.

The bits of wood clamped round the shaft will do perfectly well for measuring torque.

Clamp it solid and measure the pull at the end of the wooden leaver with a spring balance, keeping the pull at right angles to the lever arm. Pull x radius gives starting torque.

You can get a load figure if you loosen the clamp bolts and let it slip on the shaft.

Give it a spin to bump start if necessary and tighten the clamps to drag the rotor down to about half speed and measure the torque. If you can get a figure for torque, speed and wind speed you are well on the way to decide how big an alternator you really need.

If the speed is incredibly low you may need that diameter, but there is no point in doubling up on the magnets if you can get what you want without. It will not be anywhere near as efficient in materials or output as a dual rotor but should still work well enough. I think you will be best avoiding any form of iron as starting seems to be a big worry.

Flux

vawtman · « **Reply #15 on:** April 17, 2007, 02:30:42 PM »

Hi Tom

The poles are more or less a power pole cut in half.14ft long each with 6 of that inground.

Is it rigid enough for the forces?Yes,but when the turbine hits around 180rpms she'll shake um.Still need to add the other blades.That little turbine in the background has seen 60mph wind but has only a fence post and it actually bent it.Funny it didnt break.

Could you do quick sketch of your idea i promise not to laugh.

Thanks for the reply.

willib · « **Reply #16 on:** April 17, 2007, 03:34:27 PM »

You could try sixty magnets , at 6 degrees each with 45 coils

the distance between each mag where they touch the wheel is 0.733 inches, for a 32 inch dia wheel.

vawtman · « **Reply #17 on:** April 17, 2007, 04:06:19 PM »

Hi Edaddy

The wife has been very supportive.With this disease you need all the support you can get and the other one if i quit smoking could buy 2 mags a day instead of 2 packs.Boy thats enough to make any wind turbine freak quit smoking.Might be a great incentive for this one.Hmmmm

I know i have unfinnished ideas.Has do many of us.Always seachin for the cats meow.

Im sota in unchartered waters here.

Thanks for the replies.

vawtman · « **Reply #18 on:** April 17, 2007, 04:34:11 PM »

Willib thanks ALOT for taking the time to draw this up.Make a spacer and your off.

Now off to more thinkin about stator construction.

Wish i knew how to bring up a big smiley face.

vawtman · « **Reply #19 on:** April 17, 2007, 05:11:24 PM »

Hi Stone

The thickness of the rim ranges from 3/8in and gradually slopes to 3/4in at the center over the 4in width.The outer is flat.

I know the right epoxies that will work for adhesion.

How are the plans for the stator?Was thinkin using pole shoes like the little f&p motors.Any thoughts?

Thanks for all the advice overtime.

vawtman · « **Reply #20 on:** April 17, 2007, 06:05:27 PM »

Hi Flux

The rotor is 4in wide and the mags 2in long.I wouldnt be stacking them just end to end to cover the width.

Has far has startup torque goes.Ive seen it drag a cement block trying to start and winding a cable so tight into a bearing almost busted it.Not kidding or bragging here.

If you notice the 2x4 just to the right of the driveshaft bearings thats all that holds it now in high winds.Kinda weird that it wont backup just stays snug no matter how swirly the winds.Been through 60 mph winds like that and stayed there.

I think it will cook the axial i thought would work.

We can beat this beast.Im sure i will need to have a shutdown mechanism unless the additional blades run it into stall.

Thanks

Flux · « **Reply #21 on:** April 18, 2007, 03:34:53 AM »

The salient pole type construction of the F&P makes a much better synchronous motor than alternator. If you keep the poles long you have lots of leakage reactance, If you make them short then they are just coarse slots, with the associated cogging problem either way.

With that size beast I don't think you will have the facilities to produce an iron core. I also don't think you have the power available to justify the effort, just as I suspected you wouldn't justify using twice the number of magnets to cover the full 4" width. If you want to use some form of iron core then a stack of ring laminations without teeth round the outside of the coils would about double the flux without any cogging, but I can't imagine how you are going to produce it.

You may have a reasonable torque, but at incredibly low speed, if you insist on direct drive you will end up with a monster alternator for very low output. In this case I am sure a reasonable sized dual rotor ( free of cogging) and a timing belt speed increase is the most cost effective way.

If you must chase the direct drive route I still think you need to sort out the turbine characteristics, I think the power you have available is modest and there is no way to justify the cost of hundreds of magnets.

Flux

Norm · « **Reply #22 on:** April 18, 2007, 08:15:37 AM »

Just gear it up and run a motor conversion or

direct drive to a slow speed air compressor.

BTW what size is that shaft?

( :>) Norm.

dinges · « **Reply #23 on:** April 18, 2007, 08:53:46 AM »

Why gear it up?

My motorconversions (all 3 of them) have the problem of cutting in at a too low RPM, with the stock winding. For example, the latest conversion, a 130W 3 phase 220/380V induction motor, cuts in at 80 RPM (@12V). Oh yeah, those 80 RPM is in open delta, i.e. each phase rectified separately and the DC outputs paralleled. If not, it would probably cut in, in star, at 50 RPM. Which is way too low for a HAWT.

So a simple Zubbly motor conversion with original stock winding might make a good generator for vawtman's contraption. No need for any gearing.

Here's a curve of the 130W genny, charging a 12/24/48V battery:

http://www.anotherpower.com/gallery/dinges/130W_genny_graph_output_001

That is the graph of this induction conversion: http://www.anotherpower.com/gallery/album49

willib · « **Reply #24 on:** April 18, 2007, 10:09:35 AM »

Hows this for an idea

i used emachineshop and msPaint to make the drawing

the distance between magnets at the perimeter was not 0.733 it was really 0.676 inches sorry , dont know how that happened ..

the magnets are in blue, the coils have their respective colors

i had to linearize the standard way i make my alts , to figure out how the RACA should maybe look.

the advantages of this method are that the coils do not overlap, and therefor you can dississemble it if need be.

and the coils can be made seperatly , on a fixture, and can be made to fit the magnet length (2 inches) more closely than if they were overlapped. thus using a LOT less wire .

each coil 'Leg' can be 1 inch wide

vawtman · « **Reply #25 on:** April 18, 2007, 03:27:27 PM »

Thanks again Willib

That would be cool for 3 ph.

What do you think about 60 coils where 2 coil legs would share the open slot between the mags?Single phase hmmm

Ive got access to oodles and oodles of stator lams and was thinkin of cutting them in small sections and more or less making odd looking transformers LOL and bolting them to a outer band?Ill make one up so you kinda get the idea.If a coil fails for some reason just repair it and put back.One could adjust the airgap also.

P.S.im not going double wide with the mags.

vawtman · « **Reply #26 on:** April 18, 2007, 03:52:38 PM »

Thanks Flux

The turbine has a tsr~2.So not buy any means low speed its a fat bladed Darrius type (contraption).

vawtman · « **Reply #27 on:** April 18, 2007, 03:56:19 PM »

Norm, the shaft is 1 1/4 now but plan to upgrade 1 1/2.

Thanks and may need your counseling.

vawtman · « **Reply #28 on:** April 18, 2007, 04:50:52 PM »

Edaddy,I forgot to mention earlier.CONGRATULATIONS !!!!

Hope to join ya.

willib · « **Reply #29 on:** April 18, 2007, 06:53:53 PM »

i dont think much of the single phase idea, or the laminates

the RACA as proposed by Ed and Joe , did not have any laminates ,and with your 15 coils per phase you would only need about 0.66 Volts ac per coil ,to get 14 V dc out and at that dia it should be easy

it really seems like a perfect match to your Vawt.because you have a high torque slow rpm VAWT and an alt that doesnt need a lot of speed to produce power.

as soon as you get your wheel mounted on something you can start testing coils.

one question , does the wheel have bearings?

if not you could just get a shaft to fit it , throw on some bearings and spin it vertically just for testing

vawtman · « **Reply #30 on:** April 18, 2007, 07:24:43 PM »

Willib, Im gridtied and would like to drive water heating elements or an inverter to feed the grid with this without batteries.

So would need to get the voltage up higher.

The wheel has no bearings just a keyed 1 1/2 shaft from what i can tell.

Thanks

electrondady1 · « **Reply #31 on:** April 18, 2007, 08:32:51 PM »

hey,

it's a little bit like that famous medieval argument about how many angels can dance on the head of a pin ! lol.

jmk · « **Reply #32 on:** April 19, 2007, 06:43:58 PM »

This is going to be really interesting. It looks like it would work great to me. It makes me want to make a vawt. If I didn't live in a wooded area I would. Ya, and to think you wanted to change your name from Vawtman. Does it shake the poles because it's out of balance, or are the poles not firm in the ground? It must be hard to balance one of those. I think I would try to balance it inside horizontally. Of course it might be to big unless you can put it in a barn. Maybe make a tent out of 2 by 4 and tarp?

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Author Topic: 32in Radial alt (Read 5599 times)