| Post Info | TOPIC: New Project for a VAWT wind turbine with double coil stators. |
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aussepom
Member
Posts: 3
Date: Feb 21, 2010
| RE: New Project for a VAWT wind turbine with double coil stators. |
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Hi Mr Chulito
This is my first post on this site I have been looking into what others are doing turtle put me onto this site. Looking at your proposedunit, is similar to mine, it is not a wind unit but it will have two middle stators and three rotors. As for holding in the magnets, you say you have a good machine shop. Drill the hole right through if you are using round rod mags, allow 7mm at each end of the hole more than you mag, so if you use a 25mm long mag plus , 39mm, 5 mm back cut in a groove for a circlips, this will hold in your mag and still leave a hole for the flux. ausepom |
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aussepom
Member
Posts: 3
Date: Feb 21, 2010
| RE: New Project for a VAWT wind turbine with double coil stators. |
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Hi Mr Chulito
This is my first post on this site I have been looking into what others are doing turtle put me onto this site.
Looking at your proposed unit, is similar to mine, it is not a wind unit but it will have two middle stators and three rotors.
As for holding in the magnets, you say you have a good machine shop. Drill the hole right through if you are using round rod mags, allow 7mm at each end of the hole more than you mag, so if you use a 25mm long mag plus , 39mm, 5 mm back cut in a groove for a circlips, this will hold in your mag and still leave a hole for the flux.
ausepom
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Hobby VAWT
Member
Posts: 22
Date: Feb 2, 2010
| RE: New Project for a VAWT wind turbine with double coil stators. |
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Very interesting proposed project. Due to the size of the building you are powering I would suggest the use of multiple VAWTs and alternators or a phased program in which the VAWT(s) is/are placed into service with single stator alternators then upgraded with your new dual stator alternator.
Reasons:
1. Reduction of R&D costs by reuse of traditional systems, designs and equipment.
(There is a lot of blood letting for cutting edge technology)
2. Removal of single point failure.
3. Allowance for maintenance of one system while the other remains online.
4. Goals need to be acheivable within a reasonable budget and time frame.
You have a large building top to work with so "foot-print" issues are not a concern.
The harse environment of high wind and tropical storms will need to be considered into the maintenance and repair of the systems.
I have faith you will be sucessful, however there is a bit of a learning curve and goals need to be acheivable...I would suggest your dual stator design be your 3rd project.
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Caleb
Senior Member
Posts: 473
Date: Feb 1, 2010
| RE: New Project for a VAWT wind turbine with double coil stators. |
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Nice looking coils and mold. I think you will find that your voltage waveform is a little odd since there is a gap beween the coils.
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- Bryan
Mechanical Engineer turned stay-at-home dad. |
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MrChulito
Member
Posts: 14
Date: Feb 1, 2010
| RE: New Project for a VAWT wind turbine with double coil stators. |
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guys, this is the first mold/casting of this prototype project
here is one of the 2 : 3 phase, 9 coils assambly seatted on a mold of 12 1/4" diametter (mold made of a Porcelain Tile 18x18 and a 12 1/4" ID wood mold), it's been properly spaced by by wires to keep it from been too close to any of the faces once the casting heals. I'll post more pictures once the mold is done.
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Mr Chulito |
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Caleb
Senior Member
Posts: 473
Date: Oct 28, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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| ny_dave wrote:
I'm new to this forum but have a question on using the 3 magnet layers. how would you keep the center layer magnets in position. I thought that aluminum when contained within a magnetic field acted like a break by forcing the magnetic flux to loop back on its self when its in motion.
The magnets in the center layer would be spinning with the turbine. An aluminum plate would not be a problem there because it is not moving relative to the magnets. An aluminum plate becomes a problem if it is stationary like the stator. The magnets move over the aluminum and you get eddy currents that act as a brake on the turbine and just generate heat. At least, that is my understanding of it. I welcome corrections.
- Bryan
Mechanical Engineer turned stay-at-home dad. |
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ny_dave
Newbie
Posts: 1
Date: Oct 28, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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I'm new to this forum but have a question on using the 3 magnet layers. how would you keep the center layer magnets in position. I thought that aluminum when contained within a magnetic field acted like a break by forcing the magnetic flux to loop back on its self when its in motion.
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psiborg42
Veteran Member
Posts: 37
Date: Jul 25, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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most of the newer lawnmower and weed eater flywheels use the aluminum/steel magnet with no problems but on this kind of project having the aluminum around the outer edge will help with the structural integrity, it also allows for Iron beside the magnets for those who want to test theories on flux (aluminum being easier to machine than steel.)
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Caleb
Senior Member
Posts: 473
Date: Jul 16, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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I would put some epoxy on the magnets as well as pressing them in. Aluminum may expand a bit more than the magnet and you could lose them if it gets hot.
__________________
- Bryan
Mechanical Engineer turned stay-at-home dad. |
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sjh7132
Guru
Posts: 1252
Date: Jul 15, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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I think magnets without steel backing will be much weaker than those mounted on a steel plate. Even if you use both sides of the magnets, I don't think you will come out ahead power-wise.
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Steve
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psiborg42
Veteran Member
Posts: 37
Date: Jul 15, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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still working on the flux concepts, but the aluminum also has the benefit of not being attracted to the magnets while attempting the press procedure.
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Caleb
Senior Member
Posts: 473
Date: Jul 12, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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| psiborg42 wrote:
"by not putting a steel place behind the middle magnets disc I plan to use both faces of the magnets in the middle for extracting more out of the single line of magnets in the middle"
Just curious, what material to you intend to use for the magnet rotor? With rotation sometimes exceeding 1500 RPM, fiberglass resins and plastics are susceptible to come aparts. Also I have noticed that the steel increases the magnetic forces in the rotor, or seems to. When the economy straightens back up, I will talk to a couple of my machinist friends and see about having rotors cut so the magnets can be pressed in.
My reasoning for this is easy to balance, less chance of come apart at high rpm, and long-term durability. Along with this is the side benefit, that once it's built I can add as many rotors as a shaft will allow, and I can have the machinist produce.
An electric motor, running off of the first two stages; the rest produces power for the inverter.
I think you could hold the magnets with a plate of aluminum; the magnets pressed in as you suggest. I'm guessing that pressing magnets into steel would not work well because the steel would "short circuit" the magnetic circuit. It would provide a direct path for the lines of flux coming out of the north face to be directed to the south face with no benefit to the generator.
- Bryan
Mechanical Engineer turned stay-at-home dad. |
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psiborg42
Veteran Member
Posts: 37
Date: Jul 12, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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"by not putting a steel place behind the middle magnets disc I plan to use both faces of the magnets in the middle for extracting more out of the single line of magnets in the middle"
Just curious, what material to you intend to use for the magnet rotor? With rotation sometimes exceeding 1500 RPM, fiberglass resins and plastics are susceptible to come aparts. Also I have noticed that the steel increases the magnetic forces in the rotor, or seems to. When the economy straightens back up, I will talk to a couple of my machinist friends and see about having rotors cut so the magnets can be pressed in.
My reasoning for this is easy to balance, less chance of come apart at high rpm, and long-term durability. Along with this is the side benefit, that once it's built I can add as many rotors as a shaft will allow, and I can have the machinist produce.
An electric motor, running off of the first two stages; the rest produces power for the inverter.
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MrChulito
Member
Posts: 14
Date: Jul 11, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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Everyone, within a month my first prototy will be ready for a spin but I had to change my theory from VAWT to HAWT due to efficiency,
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Mr Chulito |
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Caleb
Senior Member
Posts: 473
Date: Jul 11, 2009
| New Project for a VAWT wind turbine with double coil stators. |
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I'd buy an off-the-shelf generator for a turbine that large. When I got some data on the turbine itself - torque, RPM vs. wind speed etc. then go about making my own generator.
Considering that you want to make more than one of these, it would be very good to get some experience with one before making the others. As Steve has pointed out to me before, the wind is brutal. Things break where you least expect. I think just about every nut on my windmill has vibrated loose at one point and I found corrosion on stainless bolts of all places. Simple is good. I'd have to agree with the others that a large diameter generator with two plates will serve you better than three layers of magnets and two stators.
You have a very enviable position: lots of tools, lots of space, lots of battery capacity, a tall building, and apparently the means to accomplish your goals.
-- Edited by Caleb on Saturday 11th of July 2009 01:40:09 PM
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- Bryan
Mechanical Engineer turned stay-at-home dad. |
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abid
Veteran Member
Posts: 54
Date: Jul 11, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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Hugh Piggot advises that a bigger dia rotor and stator rather one on top of the other has much better efficiency. Wonder what results you got out of what you have proposed/built?
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psiborg42
Veteran Member
Posts: 37
Date: Apr 13, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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Any one have jig plans for winding coils? I am going to try building one of these radial alts for my motor home.
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vawtman
Senior Member
Posts: 251
Date: Mar 25, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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| Mr chulido Many posters have brought your design up over the years and it usually ends up going back to the dual rotor.Seems a bit wacky to go through all that trouble when you have only so much.
Start building and learn has you go.Can't wait to see your Vawt. |
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sjh7132
Guru
Posts: 1252
Date: Mar 25, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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Mr Chulito:
It sounds like you have a good idea of the batteries you want to use. Have you picked out a charge controller and inverter yet? The charge controller will probably drive the requirements of what your turbines need to put out for voltage.
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Steve
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sjh7132
Guru
Posts: 1252
Date: Mar 25, 2009
| New Project for a VAWT wind turbine with double coil stators. |
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Here is a diagram of the magnetic circuits of both models.
Lets take some wild guesses at some values and calculate the flux. (unitless since these are really wild guesses.)
Magnetic potential of the magnet = 10
Magnetic resistance of the path through metal = 10
Magnetic resistance of the path through the airgap = 100
Like i said wild guesses, but the ratios probably are pretty good.
Just like electronics:
Current = voltage / resistance
magnetic current (flux??) = magnetic potential / magnetic resistance
Lets calculate the flux (magnetic current in the single stator model)
F = (10 + 10 + 10 + 10) / (10 + 100 + 10 + 100) = 40 / 220 = 0.18
Now lets do the double stator model
F = (10 + 10 + 10 + 10 + 10 + 10) / (10 + 100 + 100 + 10 + 100 + 100) = 60 / 420 = 0.14
So I have a hunch the flux would be lower in the double stator model because of the additional airgaps in the path, even through there are additional magnets.
But like I said, you really need to use some magnetic analysis tools to figure out what the 'resistance' of the airgap and metal are.
Disclaimer: I'm not really an expert in magnetics. I had classes in it 25 years ago, but not sure I remember it all.
-- Edited by sjh7132 on Wednesday 25th of March 2009 05:54:51 PM
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Steve
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MrChulito
Member
Posts: 14
Date: Mar 25, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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=====That's only half the circuit, you have to completel the loop by going back through one of the neighboring magnets. The magnetic circuit doesn't care about the coil, it just looks like air.
so the circuit really is:
steel - magnet - airgap - magnet - airgap - magnet - steel - magnet - airgap - magenet - airgap - magnet"=====
I see your point, taking what you are saying and layit it as follow:
steel - magnet - airgap - magnet - airgap - magnet - steel
would that not give me the same with less resources?, I think the one u just mentioned is a tri-coil arrangement, mine is only double coils.
please verify
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Mr Chulito |
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sjh7132
Guru
Posts: 1252
Date: Mar 25, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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"steel-magnet-airgap-coils-airgap-magnets-airgap-coils-airgap-magnets-steel"
That's only half the circuit, you have to completel the loop by going back through one of the neighboring magnets. The magnetic circuit doesn't care about the coil, it just looks like air.
so the circuit really is:
steel - magnet - airgap - magnet - airgap - magnet - steel - magnet - airgap - magenet - airgap - magnet
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Steve
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MrChulito
Member
Posts: 14
Date: Mar 25, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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"In the triple rotor the circuit is:
magnet - airgap - magnet - airgap - magnet - steel - magnet - airgap - magnet - airgap - magnet - steel."
In my design I plan to go :
steel-magnet-airgap-coils-airgap-magnets-airgap-coils-airgap-magnets-steel
by not putting a steel place behind the middle magnets disc I plan to use both faces of the magnets in the middle for extracting more out of the single line of magnets in the middle
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Mr Chulito |
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sjh7132
Guru
Posts: 1252
Date: Mar 25, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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It would be interesting to analyze the magnetic circuit of the 3 layer rotor. In the standard magnet / coil / magnet setup, the magnetic circuit is:
magnet - airgap - magnet - steel - magnet - airgap - magnet - steel.
(4 magnets, 2 airgaps 2 steels.)
In the triple rotor the circuit is:
magnet - airgap - magnet - airgap - magnet - steel - magnet - airgap - magnet - airgap - magnet - steel.
(6 magnets, 4 airgaps, 2 steel)
Both have 2 steel paths. The first has a 2:1 ratio of magnets to airgaps. The triple has a 3:2 ratio. I think this means the triple probably has a weaker field. (assuming airgaps are the same in both designs)
Someone would probably need to use some magnetic field analysis software to say that for sure though.
Steve
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Steve
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electrondady1
Senior Member
Posts: 430
Date: Mar 25, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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i built a few triple rotor types .
you can cast the center rotor from resin and use both sides of the mags.
if all the mags were placed on two rotors you would have twice as many poles
giving twice the frequency at the same rpm.
it would give 4 times the power of the stacked up system.
the tricky bit is syncing the multi stators
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sjh7132
Guru
Posts: 1252
Date: Mar 25, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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> Steve, how does the inverter deal with the diference in voltage input to output, if I understand correctly the wind turbine output voltage varies due to the speeds of the wind. maybe I'm mistaking.
The same is true with solar panels. The inverter actually finds the peak power point (current and voltage where the most power is made) and runs my panels in that point. The peak power point changes with light conditions and temperature, but it tracks it.
Converting voltage is what inverters do. (usually DC to AC also).
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Steve
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MrChulito
Member
Posts: 14
Date: Mar 25, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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Steve, how does the inverter deal with the diference in voltage input to output, if I understand correctly the wind turbine output voltage varies due to the speeds of the wind. maybe I'm mistaking.
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Mr Chulito |
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sjh7132
Guru
Posts: 1252
Date: Mar 25, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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My solar power system consists of my solar panels, and a line inverter. The panels provide DC power to the line inverter and the line inverter mixes that power into the AC system of my house. If my panels are producing 1KW, about 900 watts makes it into the AC. If I happen to be using more than 900W of power in my house at the time, then it just reduces my usage by 900 watts. If I'm using less than 900W, then the difference goes back to the power company and they pay me for the power. (half as much as I pay them, what a rip, eh?)
I only have 1KW of panels, but around noon the meter is usually turning backwards.
My line inverter is called a 'Sunny Boy' and it's made by SMA. They also have a 'Windy Boy' for turbines.
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Steve
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sjh7132
Guru
Posts: 1252
Date: Mar 25, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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> If I lay out the mags in 2 layers and placed all of the 2nd disc of coils into the 1st one only, will that give me the same doubleling of my output power from this generator?
No, it will be better (twice as good), but uses a few more magnets.
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Steve
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MrChulito
Member
Posts: 14
Date: Mar 25, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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Mr Chulito |
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MrChulito
Member
Posts: 14
Date: Mar 25, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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In the modified picture I noticed you placed mags on each side of the middle disc, this will just be like putting the 2 assamblies to be moved by the same blades, what I meant to explain with my design is that the middle mag disc not have a metal sheet behind it, it will only be a frame that supports the magnets but will keep both of the faces of the magnet open for the so that both sides of the middle mags disc will be used respectively.
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Mr Chulito |
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MrChulito
Member
Posts: 14
Date: Mar 25, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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If I lay out the mags in 2 layers and placed all of the 2nd disc of coils into the 1st one only, will that give me the same doubleling of my output power from this generator?
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Mr Chulito |
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electrondady1
Senior Member
Posts: 430
Date: Mar 25, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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stacking things up is a popular notion but not the optimal layout
you would make better use of your resources if you lay the mags out on two rotors and utilize a single stator
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MrChulito
Member
Posts: 14
Date: Mar 25, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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the 300AH is the amp rating of the batteries, they are 6 and 12 volts each, connect them in series and get my desired voltage,. Steve, can you tell me a bit more about line inverters?.... the project is for completely off the grid power consumption but I should add that this turbines will not be in the USA, they are going to the caribean island, Dominican republic.
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Mr Chulito |
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electrondady1
Senior Member
Posts: 430
Date: Mar 25, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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sjh7132
Guru
Posts: 1252
Date: Mar 24, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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Sounds like quite a project. Is one of your requirements that you want to be off-grid? Do you need backup power for power failures???
If not you might look at the line inverter approach. Then you just dump extra power into the power grid, and use grid power when there is no wind.
I use a line inverter on my solar power system and it's nice not to have to replace batteries.
How many volts is a 300AH battery?
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Steve
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MrChulito
Member
Posts: 14
Date: Mar 24, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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I'm shooting for 48 Volt bank of about 80 to 100 of about 200AH to 300AH batteries, planning to put about 10 of those 3kw gens on a 6 story hi building, with some type of water heater sump as part of over voltage protections mechanisms.
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Mr Chulito |
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sjh7132
Guru
Posts: 1252
Date: Mar 24, 2009
| New Project for a VAWT wind turbine with double coil stators. |
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What size wire and how many turns, how many magnets?.......
That's where things get really complicated because you have so many different things to balance.
Voltage is related to number of coil turns, number of coils, magnet size, number of magnets and speed of the turbine.
Current is related to voltage / coil resistance OR the torque limit of your turbine. If you ask too much of your turbine, it probably will just stall.
At first glance you think, I'll just use many turns of thick wire... But then you have a space constraint too. Either you run out of space between magnets or get too far from the surface of the magnet where the field gets weak.
Then your turbine probably has a 'favorite' speed and torque where it puts out the most power. Ideally you'd wind the alternator so that speed and torque puts out the volts and amps you'd like to see.
My approach is going to be build a turbine. Wind an alternator that puts out high voltage and lower current and let electronics balance it out. I have no idea how I'd ever match an unknown alternator to an unknown turnbine and get it right. But that's me. I think there are other experts on this site that may know.
What do you plan to use for a battery bank? (what voltage?)
Steve
-- Edited by sjh7132 on Tuesday 24th of March 2009 08:31:33 PM
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Steve
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MrChulito
Member
Posts: 14
Date: Mar 24, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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I see your point about starting with a small project by I tell you that with guys like you and many more on the scene I don't see how this project could go wrong, I have at my disposal a huge workshop in philadelphia and a big building that I intent to power up completely of wind turbines and a huge battery back. One more thing, what size AWG wires would you recommend for this type of turbine, I understand that the bigger the wire the more resistance and more current it can handdle.
any advise is welcome
thank you.
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Mr Chulito |
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MrChulito
Member
Posts: 14
Date: Mar 24, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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no SJH, the middle magnet disc I'm planning on making a special brakets so that the flux of each one of it's faces will not be obstructed on any one of it's faces, I'm planning to mounted on some type of frame where the edges of the magnets will be the only area of the magnet that will have something on it.
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Mr Chulito |
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sjh7132
Guru
Posts: 1252
Date: Mar 24, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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In your design, for 1.5 times the magnets and twice the coils you get 2x the power of the classic alternator with coils between 2 layers of magnets. You could almost do as well just putting twice the turns on the coils between 2 magnets.
If you went with the classic alternator, and had 2x the number of poles (2 times the number of magnets around the circle and 2 times the coils), you'd get 4x the power.
This happens because:
2x the coils
2x the change in flux per rev
The approach really depends on which way you can allow your alternator to grow, thickness, or diameter.
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Steve
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sjh7132
Guru
Posts: 1252
Date: Mar 24, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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Second comment:
How do you plan to hold that middle magnet? Is it really a steel plate with a magenet on both sides?
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Steve
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sjh7132
Guru
Posts: 1252
Date: Mar 24, 2009
| RE: New Project for a VAWT wind turbine with double coil stators. |
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I actually have several things to say to this post, but I think I will do them in separate posts.
The first is that 3KW is an extremely large first project!. Your turbine will be huge, you'll be dealing with tons of magnetic force, etc. I'd really suggest getting the hang of things in the 50 watt range first.
I used the N35 magnets from windstuffnow.com. I elected to go with a single layers of magnets and single layer of coils, even though it's less efficient, because I couldn't see how I was going to assemble 2 layers of magnets without getting my hand crushed.
Handling even a single magnet takes some care. Loose nuts fly from a foot away and hit your hand like a bullet. You try to put your screwdriver into a screw near on of these things and the magnet yanks the driver away from the screw. God help you if you let two of those things find each other! (I never have, but it's very difficult to just get one off a steel plate.)
I really suggest getting a feel for the project before diving into a 3KW version.
Steve
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Steve
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MrChulito
Member
Posts: 14
Date: Mar 24, 2009
| New Project for a VAWT wind turbine with double coil stators. |
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| Hello Guys, I've been reading tones of this from your sites and seen every one's opinions about the different designs, projects and their efficiency. Today I've desired to post my first project Idea witch I would like to add it is still in the planning stages (theories). I'm thinking about build a 3KW generator using 2 layers of 16 magnet arc shaped magnets grade n42, I've been checking the various designs out there and they are all based on a sandwich like arrangement and I thought that maybe the design could give me double the power by adding an extra layer of coils and one of magnets, how ever I'm just a beginner and don't want to re-invent the wheel. I'm looking for advised. I know I will need to get double the sweep area of the blades design in order to make it work but my question is. Can it work? and what could be the down turn of such design. Any help would be greatly appreciated. This picture represents what I'm referring to. 
Mr Chulito |
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