Volts Amps Low rpm wind turbine alternator

There are several threads on this site dealing with wind turbines, if you would search here, you will find the information you seek.

Here is a website that would be able to answer your questions.

In addition, I think you would be wise to learn the basics of electricity before attempting to build your own generator.

You do not need two different sizes of wire for the output. Volts and Amps are inter-related, search online for an explanation of Ohms law and Watts law, and you will see what I mean.

I read the voltage and amps question differently to you. I feel that he wants to use a thinner wire for the coils and then to link the coils, via blocking diodes, to the heavier wire for the current!

I could be wrong, but thats the way I read it. If I am correct, I would say that was a valid idea too....in fact, normal business so to say.....

It sounds like he wants to produce 2 different voltages at his cut in speed one for battery charging and a higher voltage for something else? though I am a bit confused how this would work with common diodes. I am not sure why 3 phase is required the windings can be series if needed this will produce a higher voltage at lower speeds.

Also it is easier to use 2 smaller wires for winding instead of 1 heavy wire

would the poster try to be a bit more specific with what he is trying to do?

Yes this is what I was thinking of.Use the heavier wire for the current and get the 14 volts from the smaller wire. While the coils were passing the magnets wouldn't both small and large size wire be making current? also with the 9 coils each 3 would be in seires to produce more voltage. So each coil would have to produce about 4 volts to get to about 15 volts to charge a battary. I under stand that this way the current would be very low untill it reached a higher rpm.

So far i have wound a coil with 200 turns and it put out about 3.5 volts at only 27 rpm. Has anyone wound coils and if so what did you get in respect to rpm, yes I know the size of the magnet and the air space.magnets neo 42. 1x2x1/2 air space of 1/8 .each side.Guess now someone that is smarter then myself in math could figure it out.How many turns [windings] per coil in series of 3 to get 15 /16 volts.This will give some loss for the 3 phase rectifier.

Thank you.

John

You have your answer with your current set up 27 rpm

One coil of 200 turns produces 3.5V :. volts per turn = 3.5/200=0.0175 volts

Therefor No turns for 16 V =16÷ 0.0175 = 914 turns ÷ 3 = 304 turns per coil

Stronger magnets will give you higher voltage and reducing your air gaps, 1/8" is a large gap

If it exists already, can we see a picture of this VAWT please?

This is a subject close to my own heart, so very interested in seeing your questions and any answers......

I don't wanna disappoint you but your thought is wrong and incorrect, are you a beginner by the way?

Since the heavier gage wire gonna produce less voltage than the battery voltage (regardless of high current) it won't be able to drive it through the load (battery) and the lighter gage wire just won't have enough current.

Besides, if you add up the two coils wire mass you will still end up using just about the same quantity of wire as if you use the rite size dia meter.

By using lighter gage wires you need to parallel them up and may be twist them but this is only if you cannot get the proper size wire which I would strongly recommend rather than use multi strand.

Believe it or not it has all been worked out long before nd there's no other way about it.

It is a nice but novice thought though.

It was not clear as to exactly who you were replying to, so I will assume the OP. I personally believe I understand where he is coming from and noted this in a previous post.....this is a perfectly valid and normal method of designing (if I understood him correctly) and keeps the weight and cost of copper to a minimum and also allows higher voltages to be generated (more turns of thinner wire against fewer turns of thicker wire) easily......

We should wait until he tells us exactly what he meant, in the case where he meant something other than what I posted/understood.......

A few minutes later after reading more posts:-

Yes, he meant exactly what I surmised. This is quite normal and usual in such cases and only needs blocking diodes to work correctly.....to my mind.....so that one energised coil does not feed into a de energised coil.....

I might have misunderstood his question.

It's happened to the best of us, his phrasing was not good, and I was just lucky.....

Hi Andy

Since the OP appears to have abandoned us, could you make a sketch of your understanding of his setup? I have yet to understand it...

Dick

Will do my best wait up a minute or two!!

My impression is something like this. The thin coil wires should be connected to the connector block Via Diodes, it was too fiddly for me so I left that out.

The thicker wires are the ones that will carry the current from each set of three, in this example, but could be 10 coils or more per phase!!....

Thanks - that helps. On the other hand, the thicker wires would only be required if the windings were connected in parallel, and I understood them to be connected in series.

Then again, if there is a significant distance between the alternator/generator and the points of use or storage, bigger wire would reduce losses...

Dick

The Voltage x Amps (Power) developed is dependant upon the strength of the magnet(s) used, the speed at which the magnets are turned and the number of turns in the coils.

In this case, more turns = higher power output. It is easier to get more turns into a specific area with thinner wire......achieving a higher voltage......even if current remains the same, a higher voltage also means more actual power.......

A more detailed (and accurate) description of Lenz's Law and several other laws pertaing to induction/magnetism can be found here:-

Lenz's Law

See also Michael Faraday's laws at:-

Faraday's Law of Induction

Also Maxwell demonstrated some interesting points at:-

Maxwell's Equations

Andy, there's something I don't understand here.

If you have thick & thin wire coils - how do you configure them to get the current of the thick wire and the voltage of the thin wire without having their voltages the same?

When you serial them obviously the impedance of the thin wire determines the current flow and when you parallel them then while the over all impedance drops the voltages got to be the same (near enough) not to cause feedback into one another.

The voltage of both coils got to be high enough to be able to charge the battery, is it not?

I think this is where I've got lost on this question because I probably did not get it right. Help me, will you!

I have posted some links today which cover all of the physical laws pertaining to this I believe.

Just remember that for voltages a thin wire is adequate, but where you start to get high currents running, you need the thicker wires. The diagram that I posted yesterday should have shown you how individual coils with relatively low currents/higher voltages can be linked via blocking diodes together to keep the voltages the same (parallel coils), but up the currents (thicker wiring for that).....

My middle name is not Faraday sadly, and I have never taught this subject ever, so although my knowledge is enough for me personally, its not good or full enough to teach! Sorry.

Careful study of the links should cover this subject in complete and full detail for you....hopefully there are a few other CR4 members around that can help us out if needed......

Hi Isti80.

I brought this point up in my post 4. You have to have matched coils on the same common circuit connection, there will be no feed back if the circuit is blocked by the diodes but two different windings will be producing different voltages on the same circuit and I cannot see the use for that. I suspected there were to be two seperate circiuts with a heavy current low voltage and the other with a high voltage and low current. But If he wants to produce 14 to 16 volts he could allways bring all the coil taps out to a switching system to series or parrallel coils to suit his wind speeds. This way all the coils are being used at an optimum.

That could be a winner!

It could also help to regulate the maximum speed of the impeller in high wind conditions, by loading it up better........though a system to move it out of the wind or furling plus brakes should never be left out of course.....

Which is why I like VAWTs, wind can come from any direction without having to turn it in some manner...., but some sort of "sock" can be pulled down, partially or fully, to stop the wind over speeding it in a storm......

"A picture is worth 1000 words'.

A sketch, drawing, or photo would help greatly! From your original post, we can't tell if you are a novice who doesn't understand Ohm's law, or someone who has a great idea but didn't communicate that idea...

Dkwarner, what's that thing called in your picture?

Recently I saw something similar to it they used it on a construction site to hold crushed stones on a slope, is this it? What's the hight of it, 2-3"?

That's BrazeFoil™ Honeycomb, the most important product produced by our original company. The mostly horizontal lines are braze alloy, which melt at brazing temperature, leaving the hexagons of Hastelloy or similar metals. The original use is for seals in turbine engines where the cell size is usually 1/32" or 1/16", but the sample pictured is 1/4" cell size, where we will add top and bottom skins to make a very strong and very light sandwich that can withstand the temperatures of jet engine exhaust. The picture covers just over a half inch square.

Further info @ aerovisionusa.com and vertechsusa.com.

Dick

Hello conntaxman:

Are you using as I understand it, the correct type of wire for the coils? It sounds like you have single core to me.

Can I ask this?........You seems to have worked things out pretty well, have you done this before or is it just something to do to see if you can? I wish you luck and will keep an eye on this thread, thanks for asking the question, OK?

This is really interesting! But a clearer explanation would be helpful please?

Take care.........................

Thank you all for any trouble or extra thinking.I will try to figure this out myself.

tks

John

I have a general question regarding the winding of coils. I have not seen mention of exactly how the coil wires are arranged in wind mill coils. Has anyone experimented with the manner of layering? There is random winding, level winding, and interlaced placement. Many years ago I ended up getting a contract to wind many coils for a then new design of switch mode power supply. Apparently it was held as conventional wisdom that cramming so much wire into such a tight space was not practical. It took great care in winding and it involved careful placement of each turn of wire to get the greatest density of copper into the available space. The end result of such wire placement in each coil was greater flux density and thus more power for a given size.

The end result was a power supply with a higher power density than anything that was available up to that point. I don't know if this is relevant to wind mill design?

BTW we also used square shaped wires in some coil designs - also to achieve greater density fill in a given coil.

I would say that your point is extremely valid, the more windings that get cut by the magnetic field, the more voltage is generated....the more coils in a design, the higher the output....

Hi Andy, my reason for asking is that in one job I was production manager of a facility that included a coil winding shop. While there I learned just how critical it could be to have the placement of the coil wires exactly right. Our coil winding machines were in effect miniature lathes complete with a "tool post" to act as a wire guide that placed the wires exactly so. Later on I did a contract job to hand make a set of transformers for a new power supply product. The so called experts at the time had exppressed the opinion that it could not be made consistently and conform to the spec. A year later I was hired as their manufacturing engineer and successfully set up a production facility that manufactured these "impossible" transformers. Occasionally we had a production item that failed to meet spec. Invariably this was traced back to improper placement of the wires in the coil. The coil winding was critical.

It was always critical and will remain so. Quality control is the first commandment here as in many other areas...

Thanks UV. I'm somewhat familiar with the concept of motor coil winding . However in all the wind mill projects I have seen they only talk about number of turns in the coil and some about wire gauge. What i am asking about is the exact placement of each wier in the sucessive layers of each coil. I'm familiar with motor coils and they are handled differently thna the coils typically used in the acial flux wind mills. A motor coil is formed on a winder then bent into shape as it is placed in the slots of the armatuer or stator. This process destroys the placement as formed in the winder. Axial flux generators on the other hand rigidly encase the coils "as formed". It appears to me that higher flux densities may be achieved with an ordered design as opposed to the random forming I see illustrated in most of the web sites.

You are correct but I would think (not know) that the field/stator windings in the book would cover that. Worse yet is I learned the what and why years ago and don't remember enough to to give even an opinion. Never used it so...

I do remember that some of the ultra high performance Hobby RC electric DC motors use square wire in the rotor to maximize current/field density. The windings were laid flat and had a specific order.

Upon reflection, all the wires are in parallel. The fields are additive. Maximum wire/field density would be stronger dynamic than any others due to the inverse square 1/r² rule.

E=E₁+E₂+E₃+....... E₁= kq₁/kr₁² r=distance between charges. Here is a power point of it here.

What this amounts to is lay your coil wires as tightly packed as you can without shorting. Also by reducing your gap between the magnets and coils by half you square the top wires lines of force. It seems to me that the coil is approximated as a whole but it has been decades.

Brad

UV wrote: I do remember that some of the ultra high performance Hobby RC electric DC motors use square wire in the rotor to maximize current/field density. The windings were laid flat and had a specific order. <snip> Maximum wire/field density would be stronger dynamic than any others due to the inverse square 1/r² rule.

REPLY

That is what I was getting at. No disrespect or criticism intended to the home brew people. But the next generation of wind generators needs to embody these known design elements in order to get better performance. Air gap is critical. I remember that some automotive alternators were built to such close tolerance that when they were over driven on a racing engine the armature pole pieces were pulled out by centrifugal force. With the gap so close ( a matter of thousands of an inch)the pole pieces struck the stator poles. Then the armature had to be machined slightly to give clearance at the tip when centrifugal force pushed the tips out.

Second element would be how to shape the coil to optimize the flux lines and the coil lines to minimize any waste of flux lines. If the shape/size of the coil did not closely match the magnet physical shape, what happens? Is a square or round or rectangluar permanent magnet better? Should the coil shape be altered to suit each kind of magnet shape. On the one hand big powerful magnets make for greater output. But bigger magnets also mean more mass and thus more flywheel inertia effect. Somewhere there is a balance between low starting torque and higher putput. To what extent does shape, size and weight of the magnets affect overall operating characteristics.

It still comes down to the flux density cut by the coil. You can shape the field as is done in loud speakers focusing the fields for both the magnet and the coil. How and what is the most cost effective way you do this depends on your application.

Brad

correct! and it is this focussing that I am askign about.