45 Coils 60 Poles where does it end ?

[willib]

where does it end , before the rotor diameter gets so large that the blades cant keep up ... wait you could allways make the props bigger, i guess it doesnt end ...

here is a 45 coil 60 POLE design..using 2" x 1" magnets..the coils and magnets are centered on a  dia. of 29.652".

http://www.otherpower.com/images/scimages/2965/45_coils_60_poles.bmp

the coils are spaced every 8 degrees and the poles are spaced every 6 degrees.

for a double rotor design (120 magnets) it would cost 1200 dollars in magnets alone.

you would only need 2V rms from each coil to get 51V output three phase star ..

i suppose the advantage of more coils is you can spread the load out over more coils..Dan dont read this. lol too late..

someone out there will make one , i know this.

[jlt]

the only thing keeping me from building this . is the cost of mags and the wire.in the mean time i still have to finish the smaller one.

[jlt]

[Waterfront]

What's that white middle (in the picture) made of? I imagine having that thick metal under those 60 mags for the full rotor would cost a fortune, not to mention weight a ton, so a different middle was probably used... Is it simply a thinner sheet of metal?

[finnsawyer]

Well, the faster the coil moves across the magnet the greater the voltage.  So, mount the coils on the edge of a bicycle rim, and the magnets on the inside of a steel ring (stator) just enough larger for the desired effect.  Sixty half inch diameter magnets might not be too expensive.  Just a thought.

[willib]

thats pretty cool , i cant really tell the number of poles on thet rotor , but it looks like 38 ?? 40 ?

what size magnets are those??

[DanB]

That's pretty JLT.  Whats the diameter of the disk there?  Are those 1" x 2" magnets?

be fun to see how that one works...  

I guess it all ends when we either run out of funds... or can't hoist it off the workbench anymore!

[nanotech]

Heh, just thought of something.  Remember how I asked about ducting a turbine?  Well, what about ducting it and using the duct as the stator?!?!?!?

Put the magnets on the ends of the blades....

Nah, would have to have a 30 blade mill then.

Unless you mounted a ring on the end of the blades and put the magnets on that then made an outer ring for the stator......

Hrm, go me thinnking now.  

[dinges]

How come you don't see commercial ducted windturbines (at least, I don't)? Is it because the people at these companies are not creative (being engineers), or BECAUSE they're engineers?

Not trying to bash someone's innovative ideas, but ask yourself why somethings haven't been done before by others. (hmm, if the Wright brothers would have asked this question...)

As to the original post (where does it end?): it doesn't. There will always be bigger and better. Fun, isn't it?

Peter,

The Netherlands.

[Dzisko]

Most of engineers are just a screws. All they need - not meet problems, and they take some ICs with their harnesses, designed by others, and they take some proven old designs, slightly change dimentions, and that is all they will do for their not so big salary, and that is his way not meet problems and after their workday go to family and not remember about that till next morning.

In case their boss (very, very rare case... Had you meet smart bosses? :-) need to build simething "revolutionary" new, he just brings to them results of a professional spying...

That is a way the science and the entire monkeynd develop.

------------

Ring on blades with a lot of small cheap magnets is a good idea, but there will he hard enough achieve good precision, hardness (wind will try bent blades and ring)  and low weight in the same time.

[terry5732]

I believe those are cheap ceramic magnets. They overcome their low power in quantity and are still less costly then neos. Cost for these 120 is probably $120 or less.

[willib]

thats true we'll soon need a crane just to get them out the door.well not me but you guys will ..

http://www.otherpower.com/images/scimages/2965/close_up.bmp

quesion dan , what ballpark figure resistance do you usually shoot for (per phase) when making your gens.?

with 15 coils per phase they would have to be very thick wire, and very thin coils..

in the close up pic, ya'all can see when you click on an object the program highlights the object, and lists its properties ( ie in this example length and width of the magnets )..

since the magnets are one inch wide i've made the coils 1/2 inch wide on the perimiter .and two inches long on the inside..

[dinges]

Nothing wrong with using or modifying proven designs; many people build gennies that are more or less the same as those from the Dans or WindstuffEd or Zubbly-conversions. This has nothing to do with underpaid engineers, but is common sense; don't reinvent the wheel (i.e., read the datasheet and manufacturers example schematics), don't make other people's mistakes (yes, others HAVE tried the ducted fan approach and failed; they just don't publicize this fact. It's only the proven designs that survive out in the real world. All the rest is just fiction, on paper or on CAD screens.

It is just too easy to lay all the blame on engineers; perhaps you could learn a thing or two from them? Like your schematic for measuring Ah's of batteries; I am looking for a good design for those, proven, that I can build myself (I don't spend money if I can avoid it).  Publishing half-finished designs (i.e., not tested with real-world components, under various conditions, with no component values) is in my opinion not good engineering practice. I'm not blaming you or something, I just wished some comments were added to that schematic, with component values and how it (should) work. That would REALLY increase the value of your idea/schematic for the rest of us. BTW, I'm not a professional electrical engineer, but being a HAM, I know the difference between a resistor and a capacitor :-)

Peter,

The Netherlands

(Mech.engineer & business economist (boss?))

[DanB]

Id agree with you to some point there... but when you add in the cost of wire & steel and added size/weight/effort in construction - I think it'd be crazy to build an axial flux machine (like the dual rotors with large airgaps) with anything less than Neos.

[dinges]

Absolutely;

Some people may only look at the cost of the magnets because they have to buy those, while they may have much of the other stuff that is needed (steel tubing, plate, bearings, polyester, wires, rectifier, mast, etc.) on hand (not everybody, but I think many t(h)inkerers have stuff like this available).

But when you do factor these other things in, plus your time and effort to expend, I'd be crazy if I wasn't striving for the best results; even if it means shelling out some hard-earned dollars (actually, Euros for me :-) on magnets. It doesn't make sense to me to do a lot of work, thinking, sweating and cursing building a genny, but limiting the performance of your product by skimping on the magnets. Even if you have to turn every penny around twice and living on a budget; even if you have ceramic magnets on hand, for free. Even if you have oodles of time, so you put a small value on your time.

The best is barely good enough for me. This doesn't make life easier, though. But it provides reliability in products (things keep working even in non-optimal conditions). My philosophy, but one I consider sound & valid.

Peter,

The Netherlands.

[dinges]

JLT,

why did you 'skeletonize' your rotor plate? Was it that way when you got it, or did you put in effort to make it that way? I think the extra inertia of a 'full metal' rotor helps to reduce vibration and cogging; downside is the extra weight, but I've never considered this a big issue, compared to all the other (bigger) forces that act on a turbine and mast. Looks pretty though.

Peter,

The Netherlands.

[harrie]

nanotech.   Your comment about a ducted turbin is exatly what ive been working on for a electric car. I may be wrong, but I feel that a intake duct like on a jet plane, from the front thru the vehical with a gen. somewhere in the duct, would be a great way to charge the batterys when the vehical is being run on gas. I think the idea of a ring around the blades with the mags on it, and stator built into the duct would work! I would build the rotor out of very heavy materal like a flywheel from a old John deer tractor, to get the advantage of the centrifical moton of the flyweel. harrie

[dinges]

You consider this to be a good way to charge the batteries when running on gas? Why not use an alternator or homebuilt genny to charge batteries, belt or chain driven, thus avoiding the need to build a funnel in your car, with prop, etc.? Seems like a very complicated solution for an easy problem, unless I'm missing something. What's the motivation for going your route?

Peter,

The Netherlands.

[richhagen]

It occurrs to me that if you continue to increase the size of the steel plate that the magnets are situated on, eventually, you will have to increase the thickness of that plate to prevent its warping under the forces of the magnets, or change its design.  The weight of the steel plate is going up by 4 times every time you double its diameter, even without making it thicker.  Blades, depending on their design, probably increase in weight in a similar ratio to the rotor plates.  This would also increase the cost and weight of the tower to support it, and this might put a real strain on DanB's pickup and other methods commonly used to raise them.  There probably is some practical limit as to what the hobbiest can put up because of the weight of the machine and the ability to raise it.  Refinements of Hugh's basic design as it scales up will probably push that limit a lot farther than it is right now though.  Maybe Hugh will design a village sized homebuilt turbine during his sabatical this coming year.  A lot of areas of the world could use one. :-)  

Rich Hagen

[TomW]

Dzisko;

Most of engineers are just a screws.

Can I ask what you guys smoke over there in your part of the world [Russia is it]? Mostly guessing by name and your attitude on Russia as your location. I used to work with some Russian Engineers and I see the same attitude in your comments. They tended to use 5 pounds of steel where a quarter pound of aluminum would work.

You make some rather wild and broad accusations and statements.

Your circuits may work but your attitude leads me to believe you don't really understand what goes into proven circuit designs.

A 150 part solution to not using a 16 pin DIP is not a very elegant solution.



he just brings to them results of a professional spying...



Just a bit funny hearing someone from that area accusing anyone of stealing plans or ideas.

You might consider the fact that you are addressing people of fairly high caliber here and not a bunch of lowly peasants you can talk down to with impunity.

Just my observations.

Oh, welcome to the board!

T

[willib]

 "A lot of areas of the world could use one( a wind generator). :-)  "

Rich Hagen

thats true!! and their governments should make the resourses available to their people , like inexpensive magnets for one..they could even manufacture turbine kits for their people..and sell them only slightly above cost..and teach them how to use them..

[willib]

the rotors could have aluminum centers and put steel only where its needed.

[harrie]

Peter. any time you drive a alternator, using a gas engine it takes more gas!!! with the duct flow, you would be just using some of the wind resistance that you already have against the front of the vehical to turn the turbine with no effect on fuel milage! Harrie

[dinges]

Nope. You introduce extra drag to generate your power.

You might just as well (or even better) use a belt to directly drive the alternator from the engine (or the wheels, if you want to use your braking energy for a short charge of the battery).

No such thing as a free lunch; pity, though.

Peter,

The Netherlands.

[Don Cackleberrycreations]

I am wondering why more dont use skelliton style rotors . It would make sense that the added air movement would help to keep the coils cooler and cooler coils have less resistance. This could make quite a difference on high watt turbines.

  The out side ring idea lends its self readily to an exercise bike and a 26" wheel with 1"x.5" neos the stator could be made in 2-4 pieces to simplify assembly.

As for the ducted fan coils in the duct ring would be difficult and heavy . magnets on the prop ring ? how ridgid do you plan to make the prop. Then you have to consider any bearing play at all in the hub will be magnified dramaticly at the ring making a consistant air gap nearly impossible.

  On a completely different subject

when computing the total square Inch of magnets face area on a dual rotor  alternator do you count a single rotor  or the total for both ? example  2 rotors with 12 1" square magnets each would the formula use 12 suare inches or 24 square inches?

[rotornuts]

Along the lines of nanotechs comment,

http://www.fieldlines.com/story/2004/11/25/43923/481

My second posting on the board in '04.

My theory was to make the rim around the blades the magnet rotor but use a cluster of coils aligned in an arc segment at the base of the magnet ring. The objective really is to maximize magnet speed rather than make a hundred and fifty coils so a segment containing 15 - 20 coils would be good enough and much much simpler to build. Cam followers could be setup at the lead and lag ends of the coil track to prevent collisions and the coil segment could be allowed to float somewhat.

It's hard to sum up a simple design with complex considerations involved but I see that others are coming up with  the same idea so maybe there's something to it. I did some simple experiments using a bike rim with magnets around the cicumference but that's as far as I went with it.

Mike

[richhagen]

Hi, I figure you probably don't see more skeleton style rotors from the folks that build them because it complicates the design, and for the size of machines usually built the weight, and usually the cooling isn't that much of an issue.  I have thought that in scaling this style up, ribbed, or spoked designs might have some benefit that justifies there use in construction.  The weight could be lighter, and/or, by adding thickness in the spokes in the direction of the axis of rotation, a stronger rotor could be made.  This complicates the design and construction.  I have found for homebuilt devices, the more complex it is, the less likely it is to ever be completed, and the more likely it is to break once it is done.  Therefore for home built designs, simpler is usually better.  Rich Hagen

Based upon my limited recollection of the subject, the surface area of the magnets on one rotor is usually used in the formulas I have seen, and the difference between a single rotor and a dual rotor in the calculations is based upon the increased magnetic field strength which you enter into the formula, or is already accounted for in it.  

[jlt]

I will try to ansure qustions about the 40 pole picture that i posted.IT is only a mock up with ceramic mags and they realy suck. with only one roter. i was testing one coil with 100 turns only made about 2volts at 60rpm.i am shure with neos  it would be a lot better.the metal ring is a cluch disc off a larg e rock truck.they were given to me I have 4 of them.It will be a duel roter machine with 18ft blades or 16ft. still plannig that. to grid tied to out backinverter.24volt. but if i can change my order it will be 48v. the other machine is a 15 inch duel roter with 16 2/1/mags with 12ft blades.will post more info later. Have to keep working to be able to afford those mags.

[paradigmdesign]

yep, unless your genny on the front can acheive 300% efficency, it won't help.  Blades are about +/-30% efficent and alternators get up in the 90%'s but not these home built ones.  If you want to charge the bats while driving off of gas, load the electric motor  directlly off the engine, or use the alternators as brakes for slowing you down. (regenerative brakeing)

[cyplesma]

I've thought of the same thing only use a low profile VAWT (max 6 in high, put same diameter as roof width) on the roof of the car. then allow sides of vawt to be unblocked so wind can be collected during parked times. of course you have to park in clear areas (not between SUVs). maybe even set up some type of mechanism to give vawt some more height while in park. uhmm a convertible vawt?

[finnsawyer]

While the ring will stiffen the blade assembly, it might indeed be necessary to maintain alignment with the stator by introducing some sort of bearing assembly.  On the other hand, just make the magnets longer so the coils always cut across the same amount of flux.  If the magnets are rectangular and the coils square this should work.  In reality, any movement of the ring means that the blades must stretch.

[Dzisko]

*Mostly guessing by name and your attitude on Russia as your location.

That is Greek name and Polish surname and what is wrong in attitude?

*You make some rather wild and broad accusations and statements.

I did not say I accuse somebody - life is paradoxal, so I can accuse myself, why do you think I accuse somebody other?

*Your circuits may work but your attitude leads me to believe you don't really understand what goes into proven circuit designs.

Hey, what is wrong in attitude? :-)

*A 150 part solution to not using a 16 pin DIP is not a very elegant solution.

I never met only-16-pin-DIP circuits, and my circuits are not 150-parts, but you are right - increasing of number of parts decrease reliability, but using of exotic ICs may make your circuit unreparable - that is hard to find 10-years ago issued ICs, and even their manufacturers do not give documentation on them - , so old good design may occure much more reliable. And circuits I draw are simple enough, almost like tasks they perform - I not see a sense insert there any PICs and other Flashes. There were times I repaired TVs and other domestic equipment and can to say - wide using of PICs and pre-programmed Flash memories in the most cases makes them unreparable...

[Dzisko]

*Publishing half-finished designs (i.e., not tested with real-world components, under various conditions, with no component values) is in my opinion not good engineering practice.

Yes, you are right, but what serious can I do in a couple hours? :-)

That was just an example, and that is why I do not show values.

When I will have some free time, I will make this working... In case I will once have that time...

*I know the difference between a resistor and a capacitor :-)

Yes, Peter, I have noticed that.

*(Mech.engineer & business economist (boss?))

Sorry, Peter... In the place where I am from the worst people usually become bosses...

In any case I did not mean you :-)