Fieldlines.com: The Otherpower discussion board
Homebrewed Electricity => Wind => Topic started by: mbouwer on November 07, 2017, 06:41:45 AM
-
Windmill friends,
This forum seems to me the right place to exchange ideas on a test setup of an axial generator.
Now I have 2 magnet rings and an axle.
-
Got 51 lamination packages now ( 20 x 8 x 8 ) cut out of transformer sheets.
I think of gluing 49 magnets 20 x 10 x 5 mm on the magnet backing rings ( thickness 4 mm)
-
Got 51 lamination packages now ( 20 x 8 x 8 ) cut out of transformer sheets.
I think of gluing 49 magnets 20 x 10 x 5 mm on the magnet backing rings ( thickness 4 mm)
odd numbers don't work for magnets.
-
Of course.
Then I can go to 48 or 54 magnets.
Or does it make sense to go to the maximum of 80 magnets?
-
With 51 packages the space for the coil-legs is 8 mm.
I tend to 48 packages with coil-legs 9 mm.
-
the mold to position the 48 blocks in the polyester of the stator.
-
Can you give us a reminder of the turbine specification you intend to build, please?
Blade diameter, airfoil type...
Generator number of magnetic poles, number of phases, expected power output...
-
Inspired by the professional windmills around, the idea is that I first need to create test setups,
to, together with windmill builders on this forum, search for a design of a light direct drive generator with operational reliability.
In doing so we must be able to build that generator with stuff that is common and easy available for me and windmill friends on the forum.
It seems to me that the generator is the most difficult component.
-
If we could manage to get more collaboration we also can use each other's molds.
-
Detail of the mold with attachment point and cutouts for the stiffening rings and the terminal of the stator.
-
The packets are now pressed in a layer of polyester. Now ajusting my coilwinder to shape 24 coils of wire 0,5 mm.
-
modified coilwinder.
-
The coils pressed in the mold.
Now I want to connect them according to the scheme in reply #870 in the topic Active Pitchcontrol.
This time with 24 coils.
-
Taken the stator from the mold. Now going on with the other components.
-
The base ring for the statorbracket.
Composed of thin sheet material to save weight.
-
Stator bracket.
-
Stator on the teststand. Next is the hub and the magnet backing rings
-
Composite hub base.
-
Hub completed.
Now I want to continue assembling the magnet backing rings.
-
Rear magnet backing ring.
With reinforcements at the fixing points I think I need to use less iron (= less weight )
-
The composition mounted on a driven yaw bearing.
All this on the upper part of a polyester cladded lattice mast.
Now shaping the front magnet ring.
-
Basis for the front magnet ring.
-
After mounting the front magnet ring.
-
To be able to manage the forces during lowering the magnet backing rings,
I now made threaded holes with removable adjustment bolts.
-
Are there in this topic shown enough details
to start a discussion of how to proceed?
-
New test rig. First I plan to tape 40 magnets 20 x 10 thickness 2 mm on both magnet rings.
-
It's a very good looking machine, MBouwer. I enjoy seeing your progress every day.
-
Thanks Sparweb,
Maybe I can about for a while make test stands like yours.
-
The test rig in reply #25 shows 1 volt at 60 r.p.m.
To scale up the stator I found transformer sheets from which I can cut 38 x 19 or 44 x 22 mm.
-
With these teeth out of stator sheet
I plan to shape a new stator of about 27.5 mm thickness.
-
On a pitch circle of 280 mm. 54 packages can be installed.
-
with 54 packages I have space for a coil leg of 8.3 mm.
with 51 -- 9.3 mm.
with 48 -- 10.3 mm.
-
A new setup.
-
What's the plan....I was just thinking ..yesterday..wounder if he ever finished up on that....😜
-
Making the hardware is what I like.
Regarding the designing of the stator I am always looking for expertise.
-
what is the diameter of your mag rotors?
-
Magnetrings:
outside diameter is 300 mm.
inside diameter is 278 mm.
thickness 4 mm.
-
About 12 inches..a working Modle. .cool.!
-
The lamination packages have to be clamped to be able to turn the winding wire around them.
Therefore I made this two axle driven coil winder.
-
First a small test set up.
Stc. ø 120 mm.
-
Cool..did you insulate between the metal plates..paint or other ? Wounder if you would see any diffrance by using a solid metal bar on something that small..
-
The mould and the superglued small laminates.
-
Thank you for the regular updates. Your blogging is not only informative, it's thought provoking.
-
It is becoming real nice I think more and more homebuilders working together.
-
A sandwich of 2 layers of polyester that forms the stator.
-
Rear view of the flange of the main axle.
Around it the 9 stator brackets.
-
The hole in the center of the stator should breathe well to the backplate. As it is now the air looks like its meant to channel between the nine brackets. That backplate should act well as both a heatsink and heat dissapator. The ability to dissipate heat would be limited only by the airflow velocity. The first rhetorical question that comes to my mind would be if one big hole or maybe a pattern of smaller holes distributed evenly around the backplate could allow air behind it (especially if designed to rotate air in vortex patterns) and move past the stator faster. I'm only thinking out loud and remember back to older otherpower stories about how hot the stators would get. But those old designs didn't seem to consider any aspect of cooling when they were assembling the stators, and maybe its not an issue.
-
Nice thoughts about the cooling to consider in my trying to shape an improved stator.
-
yours is the most confusing build i have ever seen on field lines.
it seems to have gone on for about two years and changed direction several times.
from this latest photo it shows a dual rotor set up .
if that is the case, why have you been showing bits of iron in the middle of your coils?
i also have doubts about the width of you coils in relation to the width of your magnet spacing. perhaps it's just the photo but your coil legs should be over two magnets and yours appear to be too narrow for that.
-
It shows a development that I am going through over the years.
Searching for a light, easy self to build generator with laminated iron cores in the coils.
Now the thickness of the magnets is 5 mm and the thickness of the coils ( and the lamination package ) is 14 mm.
If you want more details I always like to show them.
-
i think it's great your experimenting.
so your doing a comparison in output ?
as in between air core , iron core and your hybrid design with laminates inside the coils ?
how is that working?
why do i get the feeling it's going to cogg like a pig? :)
or the stator really shudder (huiveren) badly?
-
By testing and driving it I think I can find out about improvements.
-
Generator set up version 07-08 Stc. ø 278 mm.
-
My 20-15 alt spins over with one finger...metal cores..mounted on metal band....not sure what a 9 - 12 alt would do with 3 mags centered at any one time..the rest eather pulling or pushing...should be only a slight drag...what's your new setup..?
-
Is it possible to mount 45 coils -- 46 magnets?
-
make 46 coils for single phase .
-
Now that would cog...with metal in the coil centers..! Tried it few years back...dam near took a pipe wrench ..to spin it over..and the vibration was massive.....fun stuff....😜
-
Now prepairing laminations and magnets.
-
Testcoil 220 windings 0.5 mm. Resistance 1,2 Ω
-
3 phase..coil & # count..?
-
Looking forward to the Aeolus Windraces on 23-25 of August.
-
Glued 2 x 50 magnets 20 x 10 x thickness 5 mm. Now shaping test coils.
-
Stator has come out of the mold. Now I need a stator bracket.
-
Nice ..single phase.? Wounder if putting some lams between the coils would help out cogging wise..my coils are mounted to a solid metal ring..with metal in the center of coils..spins over with just one finger..20- 15 alt..
-
The intention is 3 phases. Question is whether cogging will be a problem.
-
What's your coil count.? Looks close to 50...
-
Cogging will be a problem.
When you include cores in the stator of a radial-flux alternator, to avoid cogging you need to design the geometry of the magnets and the cores so that, at any position, you have the same total amount of flux through the gaps between the magnets and the cores. Otherwise there will be a torque to a different position where the flux paths will be shorter. (You can get away with "something close", but not TOO far from constant. See below.)
This torque can be very strong if your geometry is off, giving you the potential vs. kinetic energy equivalent of pushing a heavy cart, with good wheels and bearings, along a paved road with regular, and very high and deep, hills and valleys. But with careful design and accurate construction you can keep the hills low enough that it isn't a problem.
Once the mill is spinning all you get from cogging is vibration. But when the mill is stopped the magnets will have pulled the shaft into a position of low energy - "the cart is in a valley". To get it spinning the wind has to push it "over the top of the next hill", after which it will get enough kinetic energy from "rolling down the hill" that the wind can easily push it over the next one. You won't have drag from generation (except for eddy current losses - which are small at low speeds) until you reach cutin.
High-TSR blades produce substantial torque when they're spinning. But when they're stopped the bulk of the airflow is detached - the bulk of the blade area is "stalled" - and the part that isn't stalled is near the hub, where it has little leverage. So they generate very little torque - much less than if they were spinning near their design TSR.
The trick is to get the cogging low enough and/or the blade's stall torque high enough that the blade breaks the cogging and is spinning with the wind no higher than that necessary to bring a spinning mill to cutin. If you need more wind than that to get the mill moving, in low but useful winds it will just sit there - or if started by a gust it will soon be stopped by a lull. Low but useful winds are exactly when you most need it to be generating whatever it can. (If the cogging is too severe the mill won't start in winds lower than hurricane force, so it becomes a decoration rather than a power source.)
Radial flux machines, usually built by converting a motor by altering or replacing the rotor, also have cogging issues. But the stator core is manufactured by stamping - a very accurate process - so it's reasonably easy to arrange the magnets on the modified or replaced rotor to keep cogging low. Axial flux machines are more "freehand" and the geometry of the magnets not optimized to make cogging suppression easy. So even if carefully designed to avoid cogging, constructing them accurately requires working to tight tolerances, while a coreless design can be built to ridiculously loose tolerance and work just fine. Cogging is not an issue at all without the stator cores.
This is why we usually use coreless stators in radial-flux machines, compensating for the longer flux path by using stronger magnets. All the core buys you is the short flux path, allowing the use of weaker magnets and/or closer magnet spacing for higher output frequency and more power from a given area.
If you have a lot of cogging, and it's a polyphase design and has a lot of poles, all is not lost. By offsetting the magnets somewhat on different pole positions you can smooth out the transitions and reduce the cogging substantially (in principle you might even be able to eliminate it). You'll want to do this symmetrically on opposite sides of the rotor so you don't introduce a vibratory force trying to rotate the axle on the other dimensions, with the stator trying to move the way a coin behaves when finally settling down after rolling. (For a single-phase design you need to switch between the field going through the cores one way and going the other way, so there's an averages-to-nothing state between them. So you're stuck with high hills and low valleys, lowering them lowers your output, and the best you can do is optimize the slopes between them.)
-
the LCM of 45 and 50 is 450, so cogging should not be too big of an issue if the geometry is correct.
when i made my 30 pole 36 slot machine, there was a 36 position cogging because the air gap was not the same thickness all the way around.
edit: there was a 30 position cog because one of the magnets had 25% of it broken off. i then glued that magnet back together.
The 180 position cog due to the LCM is almost imperceptible compared to the 30 or 36 pole cogging, of which i never actually counted to verify if its 30 or 36, but you can feel both it and the 180 LCM.
I can visually see that the air gap isn't consistent. the air gap probably isn't even round because i had welded up the rotor and then machined it in a mill, rather than a lathe, because i didn't have a lathe at the time.
compounding this particular problem is that motor used sleeve bearings so static friction is 10 times what it could be.
-
the LCM of 45 and 50 is 450, so cogging should not be too big of an issue if the geometry is correct.
The LCM doesn't have much, if anything, to do with it.
The relevant issues can be closely approximated by drawing a graph like this:
- Horizontal axis is the shaft angle, running from an arbitrarily chosen angle to the next angle where the pole pieces have an equivalent relationship but with the magnert poles, or the coil poles, displaced by one step.
- Vertical axis is the total area of the patches where part of a stator core pole is directly opposite a rotor core pole. (The height is a very close, though inverted, approximation of the energy needed to separate the poles, and the relative height of two positions of the enegy needed - or recovered - moving the shaft between them.)
If the graph is flat, you have no cogging. If the graph is hilly you have cogging. The greater the distance between the peaks and the valleys, the more cogging you have.
As you can see, the graph is dependent on the shapes and positions of the poles, but not the number of them.
-
the LCM of 45 and 50 is 450, so cogging should not be too big of an issue if the geometry is correct.
The LCM doesn't have much, if anything, to do with it.
you've never built a concentrated pole motor have you?
-
The assembly. At about 60 rpm it shows 50 volts between the phases.
Now I can measure the torque that is needed to start.
-
but this is a dual rotor axial flux alternator
-
Starting torque is 3.6 Nm. At 1.5 mm. airgab and 60 RPM. cogging problem hardly noticeable. Only a soft hum.
-
Nice..time to Fly...
-
50 volts @ 60 rpm is a powerful alternator .
-
The generatorcontroller must be made by someone with expertise in that area.
Meanwhile I can continue with the other components.
-
Yaw bearing axle.
-
Now I can mount the generator on the yaw bearing.
-
Rear view.
-
Shaping the generator housing.
-
How did you shape that and what is the material?
(You probably said it all and I missed it, in which case please point to where you did!)
Rgds
Damon
-
Hi mbouwer .
Keep your stator cooling in mind.
Rgds. Fbm
-
The material is polyester and I used a cardboard mould.
No moisture should reach the generator but I will have to make cooling fins and slots.
-
With the blade suspension.
-
slick
-
Each blade shaft is mounted with 12 x M3 bolts.
-
Fantastic. It's just begging you for blades, now. 8)
-
The slide bearings embedded in the polyester blades.
I now have the blade axles and hubs, and the foam blade cores.
-
Now the blades are 1.30 m.
I want to mount them on the nacelle in a way so that no moisture can get in.
Therefore I first have to modify the suspension a bit.
-
But I think totally rearanging the whole set up will give more benefits ( f.e. less weight )
First trying to shape a lighter hub.
-
More lightweight constructed hub and fixed magnet ring.
-
Might be giving up to much steel for the magnetic flux path...
-
Might be giving up to much steel for the magnetic flux path...
probably not, but i don't understand why the weight matters anyways.
for a .8T field strength the iron behind the magnet only needs to be a fourth of the width of the magnet.
-
In my opinion, weight is the scourge for windmills.
It costs money and it makes your turbine less manageable.
-
From my understanding the flux lines extend into the plate on all 4 sides...
-
I dunno, Jacobs had 150 pound armatures and it takes nothing to get the blades turning in a light wind. I would give up some efficiency for reliability/ strength. But I'm not sure if that is what this project is about? It all looks very impressive on the attention to detail. Are you trying to design a commercial product or is there a particular need for this turbine? I'm definitely not trying to pick, just curious more than anything.
-
From my understanding the flux lines extend into the plate on all 4 sides...
Yes, so the plate can be even thinner. if you figure the steel plate can handle 1.6T field strength while still having a permeability of 100 at that strength, then you'll only lose less than 1% of the air gap flux with a plate 1/4th as thick as the width of the magnet compared to a thicker plate where the permiability of the steel would be say, 1000 at 1.3T so for if i recall correctly OP's 8mm wide magnets you only need a 2mm thick plate. and he may not even have an 0.8T air gap flux.
-
My goal is liaising with windmillfriends to learn how to build a small reliable windmill.
Supporting frames for the blade bearing arrangement.
-
New blade suspension. Now the pitch control components have to be made.
-
Blade pitching bars.
-
Cardboard mould to shape the spinner.
-
3m. diameter blades + spinner. Now I want to apply sealing collars around the blade roots.
-
The suspension and the sealing of the blades is now light, but I find it is too complicated to fabricate.
I would like to try to shape it in a simpler way with a larger blade root.
-
The best would be to shape the whole suspension and blade bearing in composite.
-
The best would be to shape the whole suspension and blade bearing in composite.
Difficult to understand that last point, Mbouwer. Composites of all kinds are not strong against bearing stress, and they definitely do not hold a good surface finish when exposed to alternating pressure, as bearings do.
-
Let us discuss the blade suspension bearings. How can we shape a good design?
I think we can not use the type of heavy slewing ring bearings like we see in the big turbines.
-
Let us discuss the blade suspension bearings.
Certainly. You start. What do you actually plan to use?
-
As you can see on this page, and in all my contributions to the forum, it is my intention
to search for cooperation with windmillfriends for improved designs.
In reply #87 I show steel shafts and composite hubs.
It seems to me that the axes also should be performed in composite.
-
Perhaps blade adjustment will become more and more a hot item at this forum
if we can 3D print the blade bearings
-
Interesting.
The limitations in those ideas will become apparent to you soon, since you are so close to final assembly.
-
In the course of time more cooperation amongst windmillfriends will arise,
and then there are almost no limitations.
-
Blade bearings molds have to be made.
As a starting point I want to take sealing rings 100 x 125 mm around the blade roots.
-
Tryout to shape a mould for the blade axle.
-
Polyester blade axle ( 300 gram )
The idea is to insert the raw edge in the polyester of the spinner.
-
Hub mould with an edge to shape a suitable space for the blade root sealing.
-
The hub has to be inserted in the polyester blade root.
The aim is that the bolt and nut, together with the slide bearing, can shape a rotatable blade suspension.
-
Lightweight blade axle and hub.
Now I want to pull apart the bearing positions to an intermediate size of 0.5 m.
-
Modified mould.
-
Polyester blade axle (683 grams)
I want to make another one with a mounting flange.
-
Figuring out how to make a steel version with a minimum of material.
-
The cuff. Later on I want to revolve it on 100 mm diameter in the lathe.
-
Steel blade axle 1398 grams.
If I can adjust the mould of reply#117 with a flange
the polyester implementation seems better suited.
-
Happy new year to all windmillfriends.
-
You too!
Thank you Mbouwer, for keeping up the progress.
We look forward to seeing the result this year, I hope!
-
Thanks Sparweb,
It's all about sustainable energy
and I find it a wonderful hobby.
-
Back on the test stand. The generator composition as a base to mount the blade axles.
-
To shape some adjustments on the forward magnetring I taped the magnets.
-
Pressed air, vacuuming, sticky tape,
it is not yet easy to get the steel dust particles of between the magnets.
-
On this basis, I would like to make an improved implementation.
-
What would you like to improve?
Do you want to test the performance of what you have done so far?
-
My belief is that axially with laminated iron core in the coils is a good starting point.
But I think I can improve my workpiece regarding for example:
manufacturing technique
stiffer frame
smaller diameter
more precise gap width ajustment
-
You will not know what you need to improve until you put your machine into service.
I (and probably many others) have been eager to see your machine fly for a long time.
You are so close now, don't give up hope!
-
It seems important to me now to have a while to consider, build and try to improve my axial generator.
On the forum, and also in my region, I would like to meet more friends who also have that kind of ideas.
It would bring us more capabilities.
Inspiring design of Megawindforce https://www.megawindforce.com/
-
How will you know what to improve, if you do not test what you have made?
Inspiration and ideas are great for getting you started, and we have seen plenty of them in your story.
Now is the time for proof. We've all been there. Having spent so much time building something, that we are afraid to risk its failure. But if we don't overcome that fear, we will never truly know if it works or not. The internet is full of talk about ideas that don't work. You are in that special position of having something real, in your hands, and ready for proof that you CAN make it work. That is far more satisfying than talking and sharing pictures, in my opinion.
-
The design and making of a generator is rather ambitious for me.
Nevertheless I want to go on because I think I will meet friends with electrical and electronics knowledge.
That is why I also show my progress on Dutch forums as Circuits Online and Ecologieforum.
So far I have no response from others who also want to build a mill.
Meanwhile I want to try to make an improved generator version.
Later on scaling up is always possible.
-
Now is the time for proof.
Every coil input and output is connectable
But how do I go further with this stuff?
-
Sparweb and Mmurray70 inspire me to also build a test stand.
-
Now is the time for proof.
Every coil input and output is connectable
But how do I go further with this stuff?
Individually rectify each coil then add them in whatever configuration you please as long as it is balanced(don't add only 1/4 of the coils in one spot, 1/4 of the coils balanced all the way around the stator, think of star and Y connections on steroids!)
-
Even if it's a repetitive exercise, creating a diagram of the coils and grouping them to visualize the connections is very valuable.
Then as you connect them as MaryB says, you will see the possibilities for Star and Delta patterns forming.
There are probably many interesting combinations with what you have built.
-
Jerry had a few gens with each coil rectified,, https://www.fieldlines.com/index.php?topic=127282.5;wap2
-
mbouwer,
I believe that you have 50 magnets in each of your rotors and 45 coils in the stator. Can you verify if that is correct? If you tell us exactly how many magnets and coils you have, we can tell you how to wire it so you can start spinning that baby and start generating some power.
Like SparWeb said, many of us are itching to see those rotors spinning.
That test stand that you made can be used if it has good bearings, strong bolts and is anchored to a strong table.
If that motor is not DC, you will need a variable frequency drive to vary the speed.
Do you need Inspiration and Motivation?
This is a great quotation from Nikola Tesla:
“I do not think there is any thrill that can go through the human heart like that felt by the inventor as he sees some creation of the brain unfolding to success. Such emotions make a man forget food, sleep, friends, love, everything.â€
Ed
-
50 magnets 20x10x5 mm and 45 coils. Like Reply# 61 and 62
I want to reinforce the test stand. But it must not become too heavy.
Then I am able to take it along in case I find someone in Holland who can help me with testing.
-
You are right to look for more reinforcements.
Do you have welding equipment? A frame made from steel angles would be ideal.
That would also offer you ways to make a strong torque arm.
1 meter is a good length but if it's flexible there will be issues.
-
Here is a diagram of the alternator to make it easier to visualize.
[attach=1]
The minimum amount of phases that I can see is 9. That is a lot of phases.
Maybe somebody else can come up with a different configuration.
Ed
-
I see it connected with 9 phases, too.
It should run pretty smoothly. We'll see what Mbouwer gets when it's hooked up.
-
for three phases
aa|Ac|CC|cc|Cb|BB|bb|Ba|AA|aa|Ac|CC|cc|Cb|BB|bb|Ba|AA|aa|Ac|CC|cc|Cb|BB|bb|Ba|AA|aa|Ac|CC|cc|Cb|BB|bb|Ba|AA|aa|Ac|CC|cc|Cb|BB|bb|Ba|AA
each of the "|" is a coil. A is one polarity a is the other.
its a pretty simple repeating pattern. 5 sets per phase of 3 coils in series. if you get the polarity wrong on one coil you'll just have a reduced voltage in that set. since you have 5 sets of 3 coils in series, you only have one option for voltage: star or delta. (5 being both odd and prime)
there is a chance you could connect each set of 3 coils in series.. in parallel, you would have 1/5th the voltage.. and potentially a lot of recirculating current.
https://www.emetor.com/windings/
-
On schedule from Skylar/Felix Niessen http://www.bavaria-direct.co.za/scheme/calculator/
The winding scheme is now: AaABbBCcCAaABbBCcCAaABbBCcCAaABbBCcCAaABbBCcC
-
Well, it looks like you have the wiring all figured out.
If you need help with anything just ask.
When you got 50 Volts at 60 RPM last summer, how did you had it wired?
Ed
-
Starpoint: A 1 in + B 4 in + C 7 in
-
A few reinforcements and a new drive shaft with safety coupling for the test-rig.
-
It is good to see that you are pursuing the testing of this alternator. The results of the testing will be educational to you and also to the rest of us.
With the wiring scheme that you showed, 15 coils will be connected in series. At 1.2 ohms per coil, that is 18 ohms of resistance per phase. That will produce a lot of heat in the stator.
Later you might want to consider an alternative way of wiring the stator to lower the resistance. Maybe connecting some coils in parallel after they have been individually rectified to avoid parasitic currents.
A parallel wiring of the coils will produce a lower voltage, so it has to turn at a higher RPM. But since there are so many coils producing voltage, you might get a usable voltage at a reasonable RPM.
Ed
-
Looking at the test setup, I would like to ask why do you want the drive shaft to be so long? Long thin shafts develop move vibrations than short ones.
I also hope to see the final mounting of the drive motor and generator will put their axes in alignment with each other.
-
@MagnetJuice,
Now for these 45 coils the average measure is 0.8 Ω per coil
and 13 Ω per phase.
@SparWeb,
With this length of shaft I wanted to show a clear separation between the drive and the generator.
-
At 100 rpm I measure 72.5 volts between the phases and 41 volts between the phase and the 0
How to exploit this?
-
Assume we have a 3-phase winding connected in star. Assume you measure a certain open AC voltage U in between the star point and one of the open phase wires. If the coil bundles of all three phases are identical, you should measure the same voltage for every phase. However, if you measure the voltage in between the phases it will be a factor square root of three higher than the phase voltage. So now you measure the voltage over two coil bundles connected in series. The voltage is not a factor 2 higher because there is a phase angle of 120° in between the sinusoidal voltages generated in each phase.
In The Netherlands we have a 3-phase grid connected in star. The voltage in between the star point and a phase is 230 V and the voltage in between the phases is about 400 V (398.37 V). The difference is just the same factor square root of 3. What you have measured is about in accordance to this rule.
-
It's good to you're getting readings from the mill.
Do you have the setup to also start getting Amps?
My best guess is it's going to be a high voltage low current mill.
This can be a good thing with regards to wire sizes for power distribution.
Keep going!
Cheers!
Bruce S
-
That is a good setup to estimate the power output. Find a resistor of between 30 and 50 ohms and use it for the load and measure the Amps. The resistor should be able to dissipate at least 100 Watts.
If a resistor like that is hard to find, you can use nichrome wire from the heating element of a heater or a hair dryer. The resistance of nichrome wire doesn't change a lot with the increase in temperature.
An incandescent light bulb is not good to use for this purpose because the temperature coefficient of the tungsten element is high. That means that the resistance is going to increase too much with temperature to get accurate readings. You want a known resistance value so that you can more accurately predict the alternator output.
And because the wire of those coils is so thin, make sure to MONITOR THE TEMPERATURE OF THE STATOR. You don't want to exceed their current limit and burn it up.
Keep up the good work!
Ed
-
MagnetJiuce
Is correct, I cut the wire out of trashed toasters and use those.
Depending on what you're doing, they and the stator can get toasty quickly.
Keep Going
Bruce S
-
To be able to work on the blade adjustment I want to go on with a more realistic test setup on the upper part of the mast.
-
Setting the blade pitch requires knowledge of the generator's load characteristics. I still believe you should test your generator first.
-
You are right. But electrical is not my field and I do'nt want to ruin my generator.
So I am searching for expertise around here.
Meanwhile I can work on the hardware for blade suspension.
-
With a bridge rectifier and a load you can see more.
-
You said:
“But electrical is not my field and I don't want to ruin my generator.
So I am searching for expertise around hereâ€
I'm glad you said that, because now we have a better idea about what to do to help.
That's OK, nobody can be good at everything. You are very talented. I have never seen anybody that can build all kind of parts as fast as you do.
To try to help you with the testing of your Alternator, I put together an image with the setup that you can use and some numbers to guide you along.
I decided to get this image instead of trying to describe the procedure with words. That could have been confusing. Somebody said: “A picture is worth a thousand words†I don't have time for that many words right now. (My coffee would get cold)
To make sure that you don't damage your alternator, keep your current below 2 amps.
Those coils can safely handle that load. Because they have an iron core, some of the heat will be absorbed by the core so you'll be OK.
You can use a setup with bulbs as shown by midwoud, but like I said in my previous post, you can get a more accurate power estimate by using a power resistor for the load. Try to find a resistor with a resistance of between 40 and 80 ohms and with a rating of 100 watts for the initial tests.
As for the rectifiers, those 3-phase ones are not easy to find and cost more than a regular bridge.
If you can get a 3-phase as shown by midwoud fine; if not, use 3 singles as shown on the picture. 10 amp rectifiers will be adequate. 25 amp will be overkill but they are found cheap in many places.
[attach=1]
If your tests are successful and the stator doesn't get too warm, then later you can try to increase the load to something in the range of 20 ohms. And make sure that you increase the RPM slowly.
Judging by the size and number of magnets, I estimate that alternator can produce around 200 watts or a bit more. That is if the construction is strong and the air gap is not too wide.
If you cannot get the right size and value of a resistor, you can combine resistors in series, parallel or both to get the value and power that you need.
[attach=2]
-
I forgot to tell you about the 59 Volts shown on the table. I chose that voltage because I know that the alternator can produce that much and 59 Volts would be ideal to charge a bank of 48 Volts battery.
But don't worry about trying to get 59 Volts, get whatever you can get.
Ed
-
Very usefull information, but regarding the generator
allow me to stop for a moment, and focus on a matching blade suspension.
New arm with slide bearing ø 72 mm and SS bolt M 12
-
Ok, carry on. I have other projects that require my attention too.
If you have questions, just ask.
Ed
-
Hollow blade axle mounting rings outside diam. 92 mm
-
It's true that you can better use a real resistor than a lamp bulb as load. The disadvantage of a lamp bulb is that the resistance is very low if it is cold so then it works almost like a short-circuit and you can get a very high peak current.
-
So no light bulbs as load.
The basic blade suspension ring (820 grams) loosened from the mold.
I think in the next test set up this ring can be integrated in the front magnetring.
-
What metal did you mold/make that with?
-
Small pieces of 2 mm sheet steel of ordinary steel.
To reduce weight I remove material, on less stressed places, by means of grinding.
-
Completed basic blade suspension ring (1708 grams)
Now I can go on with the blade hubs.
-
Piece of craft.
FBM
-
It is a base. There'll be additions for the blade adjustment and fastening the spinner.
Now I'm working on the polyester slide bearings which fit Reply#164
They get a wear layer of copper filings.
-
Looking at the blade suspension ring I can't help but feel your machine is going to have a lot of stress in that area Not trying to be an arm chair engineer but it looks like it is going to require another 6 sided piece of metal welded to the blade hub mounts to tie the outer edges together
-
You mean like this.
-
Yeah, something to help distribute the stress . The force on the blades will be tremendous which will try to bend the mounting plus as the blades pass the tower the forces are deflected causing that blade to try and relax a little or be deflected angular to the mounting. metal fatigue quickly sets in. Part of the reason air plane props have much stronger mountings than looks necessary. The forces are the same just opposite of how a turbine receives them transmitted from the tips inward as opposed to the hub driving them
-
One way to test your mounting piece would be to lock it down to a fixed table mount a single blade then pull on the tip forward backward and up and down simulating the wind force that will be exerted. Check with a dial indicator touching the blade hub at its mounting
-
Nice way to test the blade and the blade bearings. And to see if the blade pitching keeps on working in rough conditions.
The slide bearing and a threaded sleeve anchor is to be incorporated in the polyester blade hub.
-
Blade suspension ring assembly with the blade roots and the operating levers.
-
Pitch bearing. Now I want to make three small clevises.
-
Goodness, how I envy your fabrication skills!
Rgds
Damon
-
I must say I do too.
These last photos of the assembly reveal a lot of the machinery that (until now) has not been clear to its purpose or function.
Thank you!
-
Allow me to underline it is just a test set up.
I'm trying to improve the components and (critical) forum comments contribute to this.
-
Thank you. We enjoy seeing the progress, even as tests. Especially, so, in fact.
I am looking forward to seeing the rigging of the pitch arms, too.
-
As part of the reinforcement rods from Reply # 175 I have welded mounting plates on to the blade axle mounting rings.
-
Hey Mbouwer
Im wondering if you have made any 3D CAD models of your work.
Was in conversation with some other fellows on steamautomoble.com about a CAD software. I could give you a link.
https://steamautomobile.com:8443/ForuM/read.php?1,28227,28360#msg-28360
-
Until now I do'nt have them but perhaps I can form part of a team with multiple disciplines.
It would be nice if a CAD draughtsman could be part of the team.
Blade pitch components.
-
Feathered position. The steering rod protruding.
If I could make a main axle with a large inner diameter.
Then it would be possible to therein withdraw the clevises and the pitch bearing.
-
Found 2 scrapped bearings. I want to use the inner rings (inside diameter 110 mm)
-
In one of the rings I added a mounting ring.
And after that I grinded raceways in the sides for the new 4 mm balls.
-
Making your own bearings? This is a very unorthodox thing to do.
You have proven that your fabrication equipment is good, but making bearings requires a very high sophistication.
Are you able to answer my many questions?
Did you machine the races of these bearing? Why did you choose to do that?
Guessing by what I see in your lower picture, is there a weld in the outer race?
How did you grind the races?
How will you re-harden them?
I will start with that - I have many more questions still not yet asked.
-
Your questions are welcome.
A bearing with a larger inner diameter brings advantages. But it must not become too heavy.
The races were grinded on the lathe.
I do'nt know if I have to re-harden them since I do'nt know if the material become too hot.
-
Sparweb I am beginning to understand his methods to this build. It is a proof of concept model not meant to fly for a long life but to be used to see where certain components may further optimized or have additional structural strengths added. Finding a pair of large bearings near to the size he believes would allow the build to continue without having to search for and buy new but rather regrind them to suit his intended design characteristics even should they possibly have shortened service life would be acceptable.
At least that is what I think he is doing.
I know in the past I have had to take two different bearings and re ground the profiles to accept different sized balls then used the inner of one and the outer of another to achieve the size I needed when I couldn't locate the proper replacement bearing at the time or wait until one could be ordered,to put a machine back in service knowing it may be temporary
-
It is a proof of concept model not meant to fly for a long life
That helps, thank you Frank. I can get off my soap box now. :)
The grinding is hard to see in the photos (and looked more like welds!) but this is a way that the camera can tell lies.
Given the care and attention you've dedicated to your other work, I have no doubt that you carefully ground them, too.
I am curious about how you'll keep the balls well spaced unless you can come up with a cage for them too.
If you're looking for ideas on ball arrangements, I think I've heard of special ball spacers, which might inspire some ideas, but I don't think I could find the link to the article again. Just a strange thing I read once and this reminded me of it again.
-
Wind power is booming and I find it a pleasure to shape windmill components. And I am always willing to show details.
As you can see in all my postings it is a development and a learning curve that I am going through. Hence the exchange of views with windmillfriends is pleasant.
The objective is to achieve a small and save functioning and reliable mill in my garden.
-
I have seen nylon used as spacers for low rpm uses like this(Antenna rotors use a nylon cage for example), this is one from a Ham IV antenna rotor(medium duty rotor)
(https://www.electronicdesign.com/sites/electronicdesign.com/files/Rako_RotatorTeardown_Fig5.jpg)
It is a proof of concept model not meant to fly for a long life
That helps, thank you Frank. I can get off my soap box now. :)
The grinding is hard to see in the photos (and looked more like welds!) but this is a way that the camera can tell lies.
Given the care and attention you've dedicated to your other work, I have no doubt that you carefully ground them, too.
I am curious about how you'll keep the balls well spaced unless you can come up with a cage for them too.
If you're looking for ideas on ball arrangements, I think I've heard of special ball spacers, which might inspire some ideas, but I don't think I could find the link to the article again. Just a strange thing I read once and this reminded me of it again.
-
Why not mounting the 4 mm balls side by side.
Many balls give a low surface pressure.
-
Why not mounting the 4 mm balls side by side.
Many balls give a low surface pressure.
Many bearing design applications do not use cages or separators between the balls.
I may be wrong but from what I am seeing you are attempting to create a duel purpose bearing set that has both radial and axial thrust loading I have done this many times in a much larger scale in the manufacture of jib cranes where my bottom bearing had to preform those duties these worked perfectly although what I made was not required to constantly rotate
-
Assembly. No axial play because that is adjustable by means of the M 6 bolts.
Radial play I can improve I think by more accurate grinding.
-
By the more accurate grinding of the raceways the radial play is reduced.
Unlike Reply# 188 the pitch rods and the pitch bearing are now recessed in the main bearing.
-
I wonder if, in case of this axle low rotational speed, also a slide bearing can be used.
It is easier to construct, and I now have the main shaft (143 mm diameter)
-
Not sure in which context or application you are considering the cylindrical slide bearing for. but in general bearing surfaces of this type are seldom used for constant rotation without there being dissimilar metals as in Babbitt to hardened steel or an alloy a constant source of lubrication would be required to reduce the friction between 2 large surface areas. However all prototyping experiments deserve evaluations.
-
A brass sleeve may also work in this.
I expect this assembly will need a thrust bearing component, too. Just not visible yet among the photos. Looking forward to seeing it!
-
You mean brass lamella?
But because the surface pressure is so minimal and the speed is so low,
I thought of fitting steel on steel with grease in between.
-
No I was thinking of a brass sleeve. Not sure of the dimensions of your bearing, but judging by eye, I'd say 5mm to 10mm thickness of wall, in a cylinder turned on a lathe.
In the english language, this is called a "journal bearing". Looks like this:
[attach=1]
-
Or 'bushing'. But like was said before, you need consistent lubrication with one.
-
The hub is ø 143 mm inside diameter ( shaft is ø 142.8 mm o.d.)
I will fit a few grease nipples in it.
-
Lubricating nipples and the grease inlet holes at the tread.
Now I need the correct type of grease.
-
My new stator bracket as part of the slide bearing.
-
Of course, this bearing does not turn as smoothly as a ball bearing,
but will this be a problem at 30 rpm?
-
This I find a beautiful shape with a lot of space to mount the pitch adjustment.
-
Together with the blade suspension and adjustment rods.
-
I am, as always, deeply impressed by seeing this come together.
Can you give some general measurements of blade diameter, chord, and the range of pitch motion that is possible with your machine now?
-
It is just a test fixture. The final goal now is 5 m blade diameter, direct drive generator and a calm rotational speed of the blades.
Range of pitch motion is about 90 degrees (stroke 8 cm)
And I must say the slide bearing is not ideal due to the viscosity (very sirupy) of the lubrication.
-
Teflon sheet in the bearing may help... https://www.amazon.com/Soles2dance-Various-Industrial-Strength-self-Adhesive-TEFLON-3M-all/dp/B071GJQN4Q
Or even PTFE sheet... might hold up better depending on the stresses in that area. Telfon is soft and might flow...
-
First I want to try to improve the ball bearing from Reply #199.
Based on these rings of ball bearingssteel GCR 15
-
The bearing rings now neatly fit in each other
to, afterwards, enable the grinding of the raceways for the 4 mm balls.
-
Hub. The raceways are not grinded yet.
Weight 1950 grams.
-
In the inner bearing rings inserts are needed
to get the balls in the groove.
-
Shaft. Now I have to grind the grooves in the hardened rings.
-
The bearing weighs 3425 grams and it's enjoyable it runs smoothly with no significant play.
Now I need to modify the statorbracket.
-
Hi Rinus.
That's absolutly craft.
Do you have an angular contact bearing , because I see a window to mount the bearing balls ?
Is there a way to grease the bearing ?
Good luck ,, midwoud1
-
It's now radial with deep grooves.
But you're right that an angular contact bearing should be more suitable.
And maybe it's possible to make an adjustable design.
-
The modified statorbracket (version 27-04) is made of very thin material
and therefore I thought of local thickening of the suspension points.
-
Rear view of the shaft with statorbracket
mounted on the yaw bearing of reply #76
-
i want to encourage you by saying, if it does not work as planed it will still make a wonderful decoration for the top of your Christmas tree. ::)
-
Front view with mounted magnet disks, stator, blade suspension, pitch adjustment.
-
wonderful workmanship
-
It's clear to see that the inner diameter of my bearing does not have to be so wide to contain the bearing and fork ends of the pitch adjustment.
Therefore I now want to find new hardened rings with smaller inside diameter to shape an angular contact bearing.
-
I love following your progress
-
It's always great to look at the creations of others I also find.
With regard to the development of small DIY Mills; how can we obtain more cooperation?
-
Haven't seen an update to your design in a while and was just wondering how it is going.
-
Still trying to improve my constructed lightweight main bearing.
Housing the active pitch mechanisme in the axle is possible because of the large inside diameter.
-
To be able to grind the shaft ball grooves in 1 setup
I have made this mandrel as auxiliary material.
[attach=1]
-
Another axle in the making. Lightweight due to 1 mm steelsheet sandwich construction.
In the hardened steel rings I grind the raceways.
But first I want to shape the hub.
-
Hello,
This is fascinating as usual. I do not think I understand what I'm looking at however.
Sometimes the function of a machine or component is obvious to me, other times I fail to see it.
Can you offer a description of how this axle works?
-
The shape of the large diameter main shaft of a large turbine inspires.
I just want to try to make a well functioning model.
-
You probably already know that due to vibration issues you will need to work with locking nuts along with some sort of anti-vibration filler,
Lock-tite comes to mind.
Having had a very nice 5-cyl Mercedes 300TD the Valves also had this issue. Wear and tear due to metal-on-metal will cause uneven loading.
It'll be very interesting to see this build.
Cheers
Bruce S
-
You're right about the locknuts and the locking fluid.
But what I make now are mostly studies that I want to disassemble again.
-
You're right about the locknuts and the locking fluid.
But what I make now are mostly studies that I want to disassemble again.
Then this will be a perfect build!
I look forward to seeing the posts.
Cheers
Bruce S
-
I still don't see the relationship between the part you show you have made, and the one in your latest photo.
Yours has (I think) a series of free-floating wedges supporting a bearing race. If my understanding is correct, that would be a vibration/adjustment/bolt torque nightmare. I hope I am wrong.
-
Thanks for asking.
Reply # 237 is a professional bearing of a large turbine that I want to try to make in a much smaller version.
Reply # 234 is auxiliary material with wedges to get the shaft centric in the lathe.
Reply # 235 Clamping the shaft to grind the ball grooves.
-
The bearing of Reply # 233 taken apart.
The ajusting of the play is done through the bolts and nuts.
I would like to do that in a different way. For example with a saw-tooth shaped ring.
[attach=1]
-
An improved version of Reply # 233
The bolts are:
- to hold together the parts of the hub
- to mount the magnet rings
- for the blade suspension
-
Suspension disc for the axle.
-
Axle and suspension.
I want to make a new version of this with a larger pitch circle for the axle mounting.
-
This is the axle shape, with larger suspension ring, with which I want to continue.
The ring with the front raceway can lock the hub.
[attach=1]
-
Starting point is the outer rings of 2 discarded bearings with diameters of 80 and 90 mm.
-
After halving the outer rings I have 2 rings for the axle and 2 for the hub.
-
This hub I want to shape from a sandwich of 1 mm steel plate.
Grinding the raceways in the hardened rings afterwards.
-
Just completed further and painted the parts of the hub.
Constructing an angular contact main shaft bearing with a large inner diameter and low weight is a bit of a challenge.
My idea is that succeeding will bring many advantages.
-
Those bearing races are interesting - and a little confusing. Many questions come to mind. I cannot visualize how the bearing will work in the complete assembly. How will be balls be retained? How will the grease be retained?
I just re-packed the hubs on my utility trailer this morning, so the conventional arrangement of hub bearings is fresh in my mind. This isn't the only form of angular contact bearing, but it is the most common. The angular contact bearings with ball bearings that I've seen and used (aerospace parts) tend to have very thick races and wiper seals.
How will your bearing deal with distortion of the 1mm sheet?
-
For me it is also exciting if this will work.
Based on previous versions I arrive at this shape.
The balls are being enclosed (adjustable play) in the grease in the grooves.
The two halves that will form the hub.
The clamping points are needed for the attachment in the chuck to grind the raceways.
-
Sure, but did you weld the 1mm sheet to the bearing races?
-
The 1 mm plate is MIG ( shielding gas: mixture of CO2 and Argon ) welded all around to the hardened rings.
In addition, I made some comparable welds on another ring and tried to smash this. The welds did not break.
-
The axle shaping.
[attach=1]
-
Shaping the axle I want to start from the suspension flange.
Added 3 ( hollow) clamping points for the chuck.
-
The inner sleeve, made of 1 mm sheet steel, is welded to the suspension flange.
By using an inner and outer sleeve for the main shaft ( instead of solid ) I think I can save weight.
-
The hardened steel ring is now included and is part of the shaft
Stiffening profile is 1 mm sheet steel.
The second hardened steel ring slides onto the mounting ring.
-
The raceways in the hub are grinded out.
Now I can determine the exact dimension of the axle.
-
Shaft and mounting ring + hardened raceway ring.
To keep it firmly in place the ring has a clamp fit and 9 bolts.
-
Now I can grind the raceways in the axle rings.
-
The hub rotates neatly around the shaft
2 raceways with 61 balls each. Weight 1762 grams.
A base for the generator and blade suspension,
and with a suitable inner diameter for active pitch control.
-
Before I want to start working at a new generator on this axle above,
I want to mount the axial generator that I showed on page 6 of this thread,
on a new test rig and make a drive to test it.
-
Have you finished this test stand?
(https://www.fieldlines.com/index.php?action=dlattach;topic=149398.0;attach=11643;image)
-
No I did not continue with that.
First I now want to make a variable drive.
-
Found this discarded motor. Variable from 0 to 2300 rpm and 900 Watt.
To drive the generator at the right number of revolutions I need a gearing.
-
Here is how I did my first generator test. The pulley on the generator's shaft kept the belt on the collar of the drill-press chuck. I was able to transmit about 200W this way, and the size ratio allowed for 100 - 200 RPM. It wasn't a lot, but I only wanted to test the lower end of the power curve anyway, and extrapolate up from there. This method did not have a torque arm, so I was unable to measure the mechanical power input. I could only measure the electrical power output.
(https://www.fieldlines.com/proxy.php?request=http%3A%2F%2Fwww.sparweb.ca%2F3_Gen_MoCo%2FGE%2FGE_Test_Set-up.jpg&hash=17973e3ca1d27270b91af8fefc4c2be1f507921f)
-
Converting such a motor is a very interesting way to make a generator.
I have a few 380 motors here and I definitely also want to try it.
-
The shaft must remain free to make it possible to also test the blade adjustment in this test setup.
Therefore I mounted a V-belt "groove" against the front magnetic ring to drive the generator.
-
These gearwheels can form the right rpm speed ratio for my test set up drive.
-
Super!
I'm guessing 5:1 and 4:1 in those. That would take 3000 RPM down to about 150 RPM.
-
The final gear ratio will also be determined by the V-belt pulley.
I am trying to make a separate unit that can also be used on other test setups
-
Composing the shafts takes some time.
-
The pulley that I will mount on the gearbox.
This makes the total gear ratio about 50
-
My gear box is now ready and can be used in the test setup.
-
The generator must be able to tilt to determine the torque.
Therefore I want to attach this support ring to the stator frame.
-
This should become the frame for the test setup.
-
The motor speed control from reply # 267 does not work accurately under load.
That is why I want to use another motor. I have to make a speed variator then.
-
The drive motor is placed on slide rails. By tightening the V-belt I want to control the speed of the generator.
-
wonderful fabrication skills mbouwer.
-
Bundling our knowledge and skills can bring us (wind) energy.
-
To measure the torque of the generator, it must be able to make a stroke, and therefore it is supported on 3 ball bearings.
-
Very interesting way to do this.
Be careful to apply torque in small increments when you begin to test. Observe deflections of the fixture - the deformations will grow as the load is applied. No way to know how much torque will cause the bearings to jump off the ring, but you certainly don't want a surprise!
-
I may have to strengthen the frame.
The torque measuring arm.
I want to measure the torque in the same plane as the drive and that is why I made this shape.
-
Under the torque measuring arm a console to place my scale on.
-
All parts combined into a test setup.
Measured starting torque of this generator is 9.4 Nm.
-
wow. nice work mbouwer
-
Agreed.
It will be time to start making electrical connections, now.
IIRC, you have a large number of combinations to choose from.
-
Impressive, truly. The test set up looks like almost as much work as the build itself ;>] but valuable in the end.
Question: I assume the stated starting torque independent of the belt and pulley friction? How did you measure this mbouwer?
-
Sparweb,
Just a study how to build a test stand that maybe can also be used for other generators.That's how I see it.
Kitestrings,
The generator is driven by the motor and can actually rotate freely.
But the reaction arm prevents this rotating and presses on the scale.
-
Yes, I follow you, but if you are calculating, for example, the alternator efficiency, I would assume you need to look at power in vs. power out? I was just trying to understand how you account for the drive and pulley losses. Or, are you only comparing the electrical load on the generator relative the mechanical torque measure on the scale and moment arm?
-
So if I want to measure the losses in the drive, I also have to allow the motor to tilt.
With another moment arm attached to the motor frame.
-
Test setup looks good to me mbouwer. No wait, it actually looks amazing. I think it has more pieces than my whole turbine tower/turbine setup.
It will be interesting to see your test results.
Derek
-
Inspired by what I've been reading on the forum lately
I would also like to make a radial version.
This lamination core is 98 mm. inner diameter.
-
My intention is to make the outer diameter (now 175 mm) smaller until I have a bridge of roughly 10 mm.
Therefore I now have to make a mandrel to clamp the package.
-
Now I feel torn!
Do I applaud the initiative to begin a radial iron-core generator from scratch?
Or do I persist in asking you to test that other generator, please, since the power tests would be so interesting?!
-
Testing of the axial can happen if I meet a windmillfriend in my region who has more knowledge of electricity.
Now it's much more fun for me to try, with input of the forum,
to build a radial version.
-
The mandrel ( externally ø 98 mm ) that I need as support to reduce the outer diameter of the stator package.
-
The lamination package has been mounted on the mandrel and it's outer diameter has now been reduced to ø 147 mm.
-
The package is 34 mm wide and the bridge is 10 mm.
Now I want to shape the housing.
-
I have counted the number of armature slots in your picture and I found 30 slots. This is a very unusual number as normally it is 24 or 36 for stampings of small asynchronous motors. So you should first decide what kind of winding you want to have in this stator and what pole number of the armature matches with the chosen stator stamping. For 30 stator slots, 15 coils can be laid as every coil uses two slots. If you use a 3-phase winding, you will get five coils for each phase. With five coils per phase, you have only two options to connect the coils. One is to connect all five coils in series and one is to connect all five coils in parallel. With this stator stamping, it isn't possible to make a high pole number generator as explained in my recent report KD 708 because for this generator type, the number of coils per phase must be even.
-
Thanks for the comment. I'm going to find a stamping with a higher number of slots.
-
You can use a stator stamping with 36 slots for a PM-generator with a high pole number. My public report KD 580 describes a small 34-pole generator using the stator stamping of a 6-pole motor of Kienle & Spiess frame size 80. My public report KD 614 describes a big 34-pole generator using the stator stamping of a 6-pole motor of Kienle & Spiess frame size 132. For the small generator, all parts except the stamping have to be made. For the big generator, the housing and the shaft of a standard asynchronous motor is used.
The winding pattern of the 3-phase winding is the same for both generators and is given in both reports. In figure 1 of KD 580 you can see that the three upper coils U1, U2 and U3 are about opposite to three north poles and that the three lower coils U4, U5 and U6 are about opposite to three south poles. So it is very important that the upper bundle of three coils is connected to the lower bundle of three coils such that the voltage generated in the upper bundle is strengthened by the voltage generated in the lower bundle. If all coils have the same winding direction, this is realized if coil end UB is connected to coil end UD. To clarify this, I have added figure 1 of KD 580 as an attachment.
[attach=1]
-
A study of how to modify my lamination core so that it also looks more like the direct drive of a professional turbine ( With 20 revolutions per minute for example )
Here I have 60 slots.
-
At professional mills also the rings of the laminations are composed out of many pieces.
Can we shape a tailored package for a small radial direct drive generator?
-
2 rings to enclose the laminate package for machining and as a mold to drill.
Pitch circle ø 150 mm / drilling bit 3,5 mm
If I make 72 slots (3.5 mm width) then the teeth will become 3 mm wide.
The thickness of the bridge is then 10 mm
-
A study of how to modify my lamination core so that it also looks more like the direct drive of a professional turbine ( With 20 revolutions per minute for example )
Here I have 60 slots.
A stator with 60 slots can be used in combination with an armature with 58 or 62 poles. In this case you have ten coils of phase U, ten coils of phase V and ten coils of phase W. The ten coils of one phase are divided in two bundles of five coils which are lying opposite each other. All coils of one bundle are connected in series. The two bundles have to be connected such that the generated voltages are strengthening each other.
For this generator type, only half the magnetic flow through one stator spoke is flowing through the bridge in between the bottom of the groove and the outside of the stamping. So this bridge can be much smaller than for a generator with a low pole number. But you need a certain minimum width to make the stamping strong and stiff enough. If I look at the picture I think that the cross section area of the groove for the winding is rather small.
-
2 rings to enclose the laminate package for machining and as a mold to drill.
Pitch circle ø 150 mm / drilling bit 3,5 mm
If I make 72 slots (3.5 mm width) then the teeth will become 3 mm wide.
The thickness of the bridge is then 10 mm
If you make the sheets yourself, it is essential that there is an electrical isolator in between the sheets. This prevents the flow of electric eddy currents perpendicular to the sheets. Prevention of eddy currents prevents a strong sticking torque which is increasing about linear to the rotational speed.
-
It's my search how I can make a suitable laminates core.
I now shape the slots by grinding. Then I polish the laminates and want to glue them into a package.
Do you think the glue can form an adequate electrical isolator?
[attach=1]
-
m-
Not knowing the type of glue you will be using, however I personally would not rely on glue as an insulator.
You would be better off using shellac, or the craft paper used to build transformers.
Other will have better input tho.
Cheers
Bruce S
-
This is the glue I use to build the package.
I also wonder now if I should use stainless steel to shape the housing around the lamination package.
[attach=1]
-
Epoxy paint,,then glue ,,😜
-
The laminated stack with 60 slots for which I now want to shape a housing.
-
The housing.
I want to lock the stack between the stainless steel cooling ribs.
-
The lamination package clamped in the housing. I now want to make axle and hub.
-
Looks great ,,what type of machinery do you have,,Great work as Usual,,! What’s your plans on keeping the wire from sliding out of your Stator,,few years back I made one from wood,,wire kept working it’s way out as I wound the stator,,it was just a experiment,,flop at That,,😜
-
The idea is to later push the 30 coils in the slots along with a little glue.
Now first I want to try to make a suitable axle.
-
Thanks for the comment. I'm going to find a stamping with a higher number of slots.
yea right....the number of slots means nothing really.
Like seriously, You can have over a hundred slots lol.
Now, what kind of winding is being used on this stator? Wave? Progressive Wave? Retrograde Wave? Lap wound? Preformed coils?? Overlapped
I think 30 is actually a really nice number to start with actually.
Read some books, there are ALOT of books that break it down, and the only purpose the stator metal serves is for focusing flux.
You dont even need to plave the wires in the slots to do that either! Hence, Wave winding
-
The stator with 60 slots is now the starting point.
Around it I want to try to shape all the matching turbine parts.
For example like at this professional generator.
-
The shaft and hub with suspension flange, rotor suspension ring and blade flange.
Now I can proceed with the stator bracket.
-
The stator suspension bracket.
When I have mounted the axle and hub in the stator I can continue with the rotor and the magnets.
The maximum size of the outer diameter of the rotor may become 126 mm.
So on the circumference I have to shape 58 or 62 poles.
-
I would be very interested in seeing some pictures of these parts in progress being made. Your metal fabrication skills are amazing, and i would like to know more details how you do it as well.
-
It are those windmillfriends on the forum, who succeed in generating ( part of ) their energy needs themselves,
who inspire the most.
-
Put together it looks like this.
-
It looks to me like more and more valuable information about shaping a generator is coming out on the forum. So I will first proceed with the parts for the blade suspension.
-
Base ring for the blade suspension.
-
Fixed cover plate and blade suspension mounted.
-
Oh, very nice mbouw. I like some others would be interested in seeing how you are casting and fabricating your parts (or, maybe they are all 3-D printed... just kidding). Looking forward to seeing more. ~ks
-
It is about whether we can shape our own lamination core.
I want to try to make an improved implementation.
-
Side plates to contain the lamination core.
The idea is to make 84 slots / 42 coils.
-
The lamination core can be held together on the circumference with a lot of bolts.
I think I should take stainless steel for that.
-
To the stator support ring I added 3 suspension pads.
Now I want to try to make the shaft and the stator bracket out of 1 piece.
-
The bolts on the circumference press the laminations together.
-
The inner diameter of the lamination core is now ø 130.5 mm
The inner diameter between the bolts that hold the lamination core together is ø 163 mm
So I have 16.25 mm thickness to shape the slots and the bridge.
-
Do you have a shaper to cut the slots? Do you use a dividing head to accurately space the slots?
-
First I make a drawing and indicate with a centeringpoint where the holes should be.
After drilling and grinding the slots I polish each laminate seperately.
-
Fieldlines inspires me to also get started with an existing lamination core.
36 teeth and inner diameter ø 68 mm
-
The stator must get a suspension ring.
-
The stator lamination core is 60 mm wide and has 36 teeth.
Suppose magnets 20 x 5 and thickness 3 mm on the rotor.
3 magnets in line. Then 34 lines of magnets have to be glued.
Or 17 lines of southpoles. The steel cams between the magnets then form the north poles.
-
Will you use the existing copper winding, or put your own winding in?
-
Isn't that the big advantage if I can use the existing copper winding?
-
Yes for sure it is a big advantage. Then you need to use the same amount of poles on the rotor as the original motor had. Hiw many rpm is the motor rated for?
-
880 rpm. 0.25 Kw 400 volts
On the original rotor I count 32 poles.
-
That would be an 8 pole motor. The bars on the rotor aren't poles, they are just short circuit aluminum bars.
I think you could do the magnets just like you planned. I did both N and S poles with magnets on mine, but maybe just N would work with the steel left in place for the S poles.
-
Suspension rings for this stator.
The notch is for the leading through of the wires to the terminal block.
-
Hope I’m not talking nonsense, but if it’s full load 880rpm at 50hz, then it’s probably a 6 pole motor with a synchronous speed of 1000rpm.
-
The dataplate isn't very clear - I did some stretching and pulling with photoshop to try to get the detail out.
One thing is clear - it's got a rating for both 50Hz and 60Hz. From the more legible 60Hz data I can get it sorted out.
I believe I can read "1000 r/min" on the lower right but it is more likely to be "1080" or "1088". Either way these are 10-15% below "1200" which would correspond to a 6-pole motor.
Interesting: Motors should run at the same Volts/frequency ratio. If it's designed for 50Hz with an input of 420V, then that ratio is:
420/50 = 8.4
Using that ratio when running on a 60Hz supply:
8.4 * 60 = 504V
But that's not on the label, and neither you nor I have ever heard of a 500V AC supply. That said, I would expect to see a 480V rating, which is close enough. But actually the rated supply voltage for 60Hz operation is "440V" on the dataplate.
I think they built this motor to tolerate a lot of very poor power supply possibilities. You see some "high-efficiency" motors with specs on the dataplate that require a perfect 240V/480V power supply to get the rated power. Fair enough but in reality your motor doesn't get a nice perfect supply most of the time. The builders of this motor were probably aware of that and decided to put realistic values on the dataplate so the person using it wouldn't have to de-rate for losses.
-
I still think it’s 6 pole:
If it were 8 pole it would have a synchronous (zero load) speed of 750rpm @ 50hz or 900rpm @ 60z.
The speed of an asynchronous motor will sag under load, and usually the plate will give full load rpm.
So if the rpm values on the plate are 880 and 1088 (? That’s the uncertainty here) it would have to be 6 pole. If the 880rpm is for 60hz then it’s 8 pole.
Sorry sparweb; for some reason I thought you said 8 pole not 6 pole - only noticed my error after I’d posted - it’s been a long day ::)
-
FFD Typ DPIH 71B - 6
at 440 V y 60 Hz 1.0 A 1055 r/m 0.29 kW
It is enjoyable to work on a motor like this because I really want to participate
with the windmillfriends on the forum who are applying such a generator.
-
Oops you guys are very right. I just saw the 60 hz and 880 rpm. I should have swiped right to see the rest of the picture.
-
Now I have to make an axle and then a hub with the magnets glued to it.
-
The axle gets it's shape.
-
In the rear ring of the stator I made 12 threaded holes to bolt it to the axle.
-
The lamination core and coils are mounted on the axle.
But because it doesn't look like a direct drive with a large diameter ( low rpm ), I don't want to continue with this version for the time being.
-
Did you spin it up at all? Seems like you put a lot of work, and workmanship, into it.
What's are you thinking to do next? ~ks
-
Only a study to use a asynchrone motor as generator.
Not made a hub with magnets yet.
It seems to me that I should proceed more in the shape on the accompanying image.
-
Well why not? The path you have started recently can lead to a robust wind turbine like the ones I have built.
-
Can we say the best start is outbound from a special lamination core? One cannot buy this, but I can try to shape it from the laminations of a discarded motor.
-
After drilling holes at the circumference, and removing the teeth, the laminations can be re-tensioned with threaded rods to a package.
The inner diameter can be turned out.
I think I have good starting material then to shape a lamination core.
-
The clamped laminates for drilling and then grinding out the 60 slots with a width of 4 mm
-
The grooves will be 6.15 mm deep and the narrowest width of the bridge will be 9.5 mm
-
Grinding out the slots takes some time.
-
HOw are you making all these metal parts? Are you casting? Using parts from other machines?
Fill us in Pulleeez!
-
The laminations are polished and I sprayed a coat of paint on both sides.
-
The laminations are held together at the circumference with non-ferrous rivets enveloped with epoxy.
And after that I also coated the cooling fins with epoxy.
Now working on the rotor with the main bearing.
-
Main bearing with the suspension ring and the stator mounting brackets.
-
Nice work,,machine shop or ? Looks beyond a regular scratch built ,,what about a few picks of your shop or machine shop doing the fabrication,,😜
-
The one concern I have already is the blades may have to be really really long to overcome the weight of all the metals no?
Or is it going to be so finely balanced that turning it wont be difficult?
-
One useful factor to ask is TSR its a much smaller machine than you would expect.
-
It is a study of how I can make the mechanical part of a radial generator.
I have now assembled the stator on the main bearing.
-
Found these bearings with 60mm inner diameter.
A larger inner diameter is beneficial to accommodate the blade pitching.
Therefore the axle has to be modified.
-
Can you just mill an adapter plug to span them or will it create too much offset?
-
After welding a new piece of pipe into the suspension ring,
I machined the outside diameter on 60 mm.
-
Now I have the choice to glue on the circumference of the rotor:
--- 62 magnets
--- 31 magnets between 31 steel ribs
-
The hub with 6 ribs to bear the magnets sleeve.
Mounting the magnets is after all the other components are ready.
-
Shaft and stator are ready.
If I now make the top part of the mast and the yaw bearing, I can mount them on it.
-
The top part of the mast mounted on a jacket structure.
-
How does Mbouwer, who fabricates so much stuff, always seem to have a clutter-free space for his photos?
I fabricate lots of stuff, and every flat surface in my garage is littered with things.
My wife likes to point this out to me.
-
On top of the mast I need an appropriate, and also powered yaw bearing.
In the hardened steel rings I grind raceways for the 4 mm balls.
-
Adjustable angular contact bearing with 2 rows of 55 balls. I could use this as a yaw bearing I think.
But first I want to try to make a more compact version.
-
There are readily available yaw bearings in the ham radio world... mast thrust bearings that take the load off the antenna rotor... some minor mods and I could see one working well. DX Engineering makes one(their own design) that is very smooth and tight and would be perfect.
-
My aim is to be able to make components for myself and also for windmill friends.
Now 2 hardened steel rings composed as the basis for the yaw bearing.
Outer diameter 80 mm
-
With this yaw bearing I want to continue.
On the circumference I have to shape a gear ring.
-
The yaw bearing mounted on the mast.
-
It's outdoors. I hope that means some machines will be put into the wind!
-
Much remains to be done before the blades turn in the wind.
First I now have to mount the main bearing on the yaw bearing.
-
Looking at the ratio between the mast diameter and the width of the yaw bearing I want a new set-up.
-
The shaft and hub of the yaw bearing.
The hub, which I will now weld on top of the mast, consists of hardened steel rings.
-
The new yaw bearing fits the mast better I think.
-
Is it outdoors mBwr?
-
@ Kitestrings,
It is what it will look like when this top part is mounted on the mast.
The yaw bearing seen from above.
-
I think that is a "no" ;)
-
@ Kitestrings,
It is what it will look like when this top part is mounted on the mast.
The yaw bearing seen from above.
I live in a climate with ice and snow... there should be weep holes in the bottom of the bearing housing so moisture can drain... been there done that with ham radio thrust bearings freezing up.
-
The yaw bearing will be in the bottom of the nacelle. But even then maybe moisture can get in.
So like you say I would better drill a few small drain holes.
-
Rain doesn't always fall straight down... at time is goes by sideways... same for snow and ice... It WILL force its way into places you don't want it. Why all the ham stuff has weep holes. Tiny, to small for bugs to get in, but multiple holes in case one plugs.
-
How do they keep the moisture out at the large turbines?
An example of a first seal between the spinner and the nacelle.
-
The weep holes in the pic looks similar to a Tesla valve.
Bruce S
-
They are referred to as slinger seals
https://www.mcmaster.com/slingers/
Bear in mind that while a slinger can prevent moisture from entering the joint, it's not always perfect, and moisture may get in other ways.
So the weep holes are still needed.
-
Another study for a lightweight improved main bearing.
Angle contact bearing 2 raceways each with 67 balls 4 mm
I want to mount this one on the yaw bearing and make a new suspension for the stator.
-
If those countersunk screw heads give me a rough sense of scale, and the part is about 10 times the diameter of the screw head, then the part is about 3.5" (85mm) diameter.
-
It is about to make the components fit together.
Outer diameter of the main bearing here is 99 mm. The inner diameter must be large enough to enable a robust blade ajustment mechanism.
-
Standard bearings for the main shaft. Yet another setup.
-
Are those bearings for the rotor shaft (I assume this is what you meant), or for the yaw mechanism?
I'm curious if you do detailed drawings of the components you fabricate, or just work and rework directly in the materials? Very nice, either way.
-
It is a study with standard bearings to make a suitable main shaft.
Light weight and heavily over dimensioned so it will almost not wear and can last a very long time.
-
The main bearing based on 2 conjoined standard bearings 95 x 60 mm
It runs smoothly and has a grease nipple for relubrication if necessary.
-
Prefab parts for the suspension and the stator bracket.
-
A number of components are finished and painted so that I can assemble them.
-
Now I can continue with the blade suspension.
-
Shaping the housing. Within this I want to mount the drive for the blade ajustment and that of the yaw bearing.
-
So... what material are you using? I can't see any fasteners.
It looks like one of those materials made from calcium salts, petroleum jelly and aliphatic acids...
-
Later on I want to make the housing in polyester.
That is why I first made a mold from cardboard.
-
mould making is something i studied. i recommend you use some premixed drywall compound and a foam sanding block to give the mould a nice flat surface. then coat it with some enamel. this will be a one off piece so it doesn't matter if the mould is destroyed during the separation process.
-
These are the components covered by the housing.
The connection must fit neatly to the laminationcore.
But if moisture does get in, it can be drained off in the gutter.
-
The suspension of the blades I would like to keep as light as possible. Therefore I want to shape a tubular basic ring.
6 pads on the circumference are intended for mounting the generator rotor.
-
Further shaping the blade suspension.
-
The blade suspension still needs to be reinforced. I want to do so after mounting the blade pitching mechanism so that I can work "around" that.
-
For the suspension of the blades I made shafts and hubs.
I can then continue with the blade adjustment mechanism.
Later on the hubs will be enclosed in the polyester blade roots.
-
The blade pitch movement mechanism is about the same as what I showed earlier in this thread.
On page 7 Reply # 179 March 2019
But for the drive I would like to make a suitable direct drive motor.
-
Does the blade suspension get connected in some fashion on the side farthest from the tower? (Is that upwind?) I'm having trouble picturing how the rotor forces get transferred at the hub.
-
The aim is to make the blade suspension ridgid and light.
The blade supported in 2 places on a pivot.
I think it is also possible with a wooden blade, and I would now like to apply that too.
-
What's your ETA to final assembly?
-
Several components have yet to be made. I now have a wooden blade with the blade hub incorporated in the root.
-
This one wooden blade is made to be able to continue with the pitching mechanism.
-
Any updates mbouwer? I have enjoyed following your progress, but you gone quiet lately. ~ks
-
My impression is that there is not so much interest on the forum in developing and improving active pitch control.
And I am a little concerned about that because it is incredibly important that the turbine is automaticly under control in all conditions.
-
Furling is simpler to do with basic tools... I do not have the skills to shape metal like you!
-
don't imagine a lack of comments to be a lack of interest. your machining and welding skills are very advanced and impressive . i am looking forward to the time your machine is finished and you can give us a video of it.
-
don't imagine a lack of comments to be a lack of interest. your machining and welding skills are very advanced and impressive . i am looking forward to the time your machine is finished and you can give us a video of it.
-
I agree. It's not an approach that I have direct interest in, but I've enjoyed seeing your progress. And, your ability to model, photograph and fabricate brings your ideas to life. Impressive work. I hope you're not dissuaded. ~ks
-
If I chime in, it's to say much of the same thing. Your work is very interesting to watch take shape.
I am still looking forward to the day you can complete your assembly and make it work.
-
My impression is that there is not so much interest on the forum in developing and improving active pitch control.
And I am a little concerned about that because it is incredibly important that the turbine is automaticly under control in all conditions.
How do you propose we build that functions?
-
My impression is that there is not so much interest on the forum in developing and improving active pitch control.
And I am a little concerned about that because it is incredibly important that the turbine is automaticly under control in all conditions.
How do you propose we build that functions?
Follow his thread for an answer to that question.
-
Referring to "active pitch control". The newer members may not have come across this previous thread from Midwoud1:
https://www.fieldlines.com/index.php/topic,145925.0.html
We watched several developments of this pitch-control drive. There are many interesting functions in the control system, too.
-
Basically everything I show on the forum is meant to come to cooperation with windmill friends.
-
In my opinion, now only the real diehards succeed in building their own windmill and use the generated electricity.
It is a tough job, and when the kilowatts come in, you are no longer so inclined to modify and improve your workpiece.
-
I've never looked at it quite that way mbouwer. Well, yes we're the diehards, but I've enjoyed learning, designing, building, refinement, re-refinement, and sharing experiences here. It's the enjoyment of the journey (versus a destination) sort of thing.
I do find there are a lot of different back-grounds and approaches. I follow many discussions, that I suspect I will not pursue, but follow none the less. There's always something new to learn.
-
Given the many wind turbines around us, I think that others will also be more inspired to make small mills.
And that the possibility arises that I can cooperate with different disciplines.
-
An axial generator with 2 magnet rings and a stator.
That is what I prefer to continue with.
So I now put my radial generator study aside for a while.
-
Is your objective to never finish anything?
Aren't you the slightest bit interested in completing an assembly, to see it in operation?
-
[attach=1]
Large turbines are often radial, and for me this was a study how I could shape the mechanical components of a radial generator.
To me it seems best now to continu with the mechanical components of axial.
-
mbower;
What size magnets are you going with?
Looks interesting
Cheers
Bruce S
-
Did you ever test the electrical output of the axial you built? You were really close. Just needed to twist some wires together if i remember correctly.
I would love to see how the axial performs.
-
The test set-up of the 30 cm axial generator has been dismantled (without further testing)
The magnets may be useful in the new set-up.
-
2 ball bearings 68-40-15 as the new main bearing.
-
The main bearing composed. It is the base for a small axial generator.
Now first the stator bracket ring.
-
The base hollow ring of the stator bracket is composed of 1 mm sheet steel (important issue: weight and stiffness)
For the mounting flanges I used slightly thicker steel.
-
(Attachment Link)
Large turbines are often radial, and for me this was a study how I could shape the mechanical components of a radial generator.
To me it seems best now to continu with the mechanical components of axial.
I shall save you some headache right here and now lol
It appears that you have radials down quite nicely. Although, I would have went the segmented stator core route myself for a radial.
BUt, every single dissertation, thesis, any kind of accomplished study of axials clearly states that axials was actually the very first magnetic machine
devised around 1890s. But, real develpment has not begun until about the 1980s. Why is this? Due to the complexity of the topology. I myself have greatly considered
switching to radials because the magnet rotors would be soooo much easier to manage with accuracy. BTW, the real craze seems to be with multi layer overlapping concetrated stator coils
for the power density. And, with very long narrow trapazoid magnets. And, just having one coil not perfectly formed, means 15 percent power loss immediately.
Plus knocking due to the flux not cutting the coils at 180 degrees. Soldering the coils toghether seem to really scew up the accuracy. The only thing I can devise so far is a mould to pre pour them.
But, ive devised my own technique to pot them individually, and press them all to exact dimensions. But, you can easily double or tripple your number of coils by using overlapping coils. But, that means uptruned ends. Ive devised a method to perfectly bend them also.
I also agree, you are so close with the radials. But, looking at one of your earlier pics, it appears that I can see the fibers of your carpet? That is some massive fibers or a really small radial?
Hard to tell scale sometimes. Oh well, back to the drawing board I go lol.
-
GT,
It`s easy to read this thread, witness the process of fabrication, and jump to the conclusion that there is a goal. Fabrication is the singular goal, here. Fun to watch, but don`t get too worried about results. It`s unlikely that we will arrive at the state where things are put into operation. If we ever do, I`ll be happy to eat these words. But in the meantime, I will just be eating popcorn.
-
@Sparweb,
As you say, it is an endeavor to achieve a result in the longer term: A small windmill in the garden.
With low speed rotor blades and a small generator that delivers full power at low wind speed.
I myself do not have the knowledge to design the generator, but there the input from the forum can become important.
I now positioned the main bearing and the stator bracket with respect to the yaw bearing to make the suspension.
-
You are an artist with metal... I can stick 2 pieces together with a welder and have it work... thankfully grinders hide ugly welds! What you do? Nope! I will never have that skill level!
-
Yes. I say keep going mbou'r, once it is in the garden it will be immensely satisfying.
-
You are an artist with metal... I can stick 2 pieces together with a welder and have it work... thankfully grinders hide ugly welds! What you do? Nope! I will never have that skill level!
I second that "artist with metal"!
Rgds
Damon
-
Based on dummy magnet rings and a dummy stator, we may be able to determine magnets and coils later on.
-
With a view to stiffness and low weight, the magnet rings ( external diameter 214 mm ) are composed of thin plate.
I want to apply 3 spokes.
-
This is the rear (dummy) magnet ring.
For the purpose of mounting the magnets I should use thicker material and turn a nice flat surface.
-
The rear magnet ring is mounted on the main bearing.
Only after the length of the laminations in the coils has been determined, the front magnet ring can be mounted.
But I now can continue with the stator bracket.
-
Prefabricating the lightweight stator bracket ring out of 1 mm sheet steel.
Diameter 24 cm
-
Stator suspension.
The mounting holes on the perimeter can not be drilled yet,
because the holes are related to the number of coils ( to be determined )
-
Frame for mounting the stator bracket and main bearing on the yaw bearing.
The gutter must form the connection with the nacelle hood.
-
Rear view after mounting the various parts on the mast.
-
Front view. Added the blade suspension.
-
very nice even coats of paint.
Do you powder-coat them ?
Thanks!
Bruce S
-
By using paint (aerosol) I try to show a clear picture on the forum.
Now am I doing to make a blade suspension for 90 cm long blades.
And want to bear the blades in rubber rings to make things less heavy.
This stuff should become the blade shafts.
-
Double wall base rings for the rubber bearings.
Especially when scaling up this sandwiching can save a lot of weight.
-
The rubber is the bearing that will allow the blades to pivot, is that correct? I think I asked this before, but is there a means of tying the three rings on the outer-side of the blade plane (away for the tower)? It seems like structurally this would be needed; at scale. Looking good.
-
The rubber is meant to construct lightly with no play.
Do you mean attachment to wooden blades?
Like Midwoud who clamped the blades between 2 steel plates.
-
No, I was talking about the hub. In your picture at #461, we can see the three points of attachment for the blades, but on the side away from the connection to the yaw bearing are those flanges tied?
Similarly, on the latest photo from Midwoud turbine there is a metal ring on the top of the assembly. This would seem to offer a lot more strength to the assembly.
-
You're right, but that kind of reinforcements can be added later on.
First I want to assemble the pitch mechanism.
-
Just curious... have you heard anything recently from Midwoud. I haven't seen any updates on his turbine. Hopefully he's well. ~ks
-
Hi Kitestrings
I'm okay . We moved to an other place. I can not instal my windmill here . Hopefully later with more space.
My windmill is sleeping on the attic.
Still follow Fieldlines. And mbouwer designing his windmill, speak him every week.
Wish you all the best . Frans ( midwoud1 )
-
Midwoud had it well organized.
As you also can see in his videos on youtube, he always had the quietly rotating Piggott in hand because it was equipped with blade adjustment.
-
Thank you Midwoud for checking in. You are always welcome to stay in touch. Hope you can put your machine back in the air soon!
-
Movement mechanism to pitch the blades.
First version of a small axial direct drive motor. 9 coils and 2x10 magnets. Low rpm speed / High torque.
The hub ( = nut M 16 ) turns around the axle ( = threaded rod M 16 )
This rod then makes a longitudinal movement to adjust the blades.
-
This is the matching controller I bought.
-
This is how the packages and the coils are arranged.
I wonder if there is not an easier possibility to shape the steering of the motor.
-
motor version 1
72 revolutions per minute.
The torque is more than sufficient.
-
Would it be possible to get an exchange of views on this forum with windmill builders who actually apply active pitch control?
And to discuss the developments.
-
Hey,
Sorry for missing your post about testing the generator. It's passed its first electrons. What did you observe when you ran it (as a motor, I assume)?
-
The axial motor is part of my blade pitching test setups.
The blade suspension, the controls, the steering of the blades...
All quite complicated, so I want to discuss how to make it simpler.
-
The blades of the large turbines are suspended from heavy slew bearings.
But it seems to me that we have to find a lighter way.
-
Should we look for it in a way I showed earlier? ( Reply #87 )
No doubt there are windmillfriends on this forum who have other ideas.
-
There may be, but we're all in awe of your manufacturing skills!!
-
That (#87) seems like a design worth trying; probably lighter than the slew bearing concept.
I think one thing I might contemplate changing, would be to look at attaching or fabricating a metal flange plate for the blades on the assembly. Introducing a shaft "pocket" into the root of the blades seems like might add complexity and potential for water infiltration, and corrosion.
-
Perhaps it is an option to make the root of a wooden blade nicely round like a thick round pole.
Shaping a polyester cuff around it.
And then in that bearing letting it rotate that 80 degrees.
-
Isn't it easier to form the blades from foam cores,
which you then cover with a few layers of polyester?
-
In the meantime I am working on an electric garden tractor.
Based on the model John Deere 3020
-
What type of battery chemistry will you be using?
-
Initially I want to use the stuff from an electric wheelbarrow.
But first shaping the mechanical parts.
Just finished the axle housings and sprayed it with John Deere green.
-
Could you expand on the electric Wheelbarrow ?
Many Thanks
Bruce S
-
First let's see if I can get this small tractor to work.
-
The size of the professional turbines is increasing (Moving towards 20 MW )
Striking are the gearboxes.
A small test setup with a gear box seems nice to me.
-
In a previous test set up I had connected two separate gear boxes.
But it seems to me that it can also be more compact with one single gearbox.
-
When applying a light solid transmission between the main shaft and the generator I do need much less copper and neodymium.
Below the rear and front axle for my electric tractor.
-
The rear wheels with the flanges that I have counterfeit from the typical 3020 wheels.
-
Making a model of the 3020 I see as an exercise in between
to then continue making a model of a professional turbine.
-
The 3020 needs a 4 cylinder, and that's why I started making a crankshaft for a solinoid engine.
-
Starting with a test setup of a 2 cylinder.
I now want to make the plungers, connecting rods and coils.
-
sure, sure, make your own engine. :o
-
i'm wondering what is going on here...
-
My intention is to meet windmill friends who also want to build a real working model of a professional wind turbine.
Just like I'm now shaping a model of a tractor.
-
I built a sterling engine some years back. It worked really well, except I mage the flywheel by hand. I just bent some round rod into a circle and added some round rod spokes. It was not balanced even a little and would dang near fly off the table if I put any more heat then just a small candle to it. But it was fun to do.
I have seen some videos of some really nice ones, if you have a mill, lathe and all that stuff.
I love that tinkering in the shop time.
-
Scroll back up to find this:
and that's why I started making a crankshaft for a solinoid engine.
So, I guess it's a... umm... I dunno what that's supposed to do.
But art for art's sake is fine, and fun to look at. Pass the popcorn.
-
sure, sure, make your own engine. :o
hey wanna have it run on water also? seen a youtube vid of cracking hydrogen from water!
-
I'm watching these builds.
I'm curious about the use of the solenoids.
Bruce S
-
The shaping of a powerful solenoid engine as a drive is a problem.
Back to the components of the electric wheelbarrow.
-
I have been playing in the shop as well. It is chilly, but not cold here yet, so I am able to still get out there a little.
I am taking my wash machine motor (it is ac and no brushes) and building a stand for it and wiring a light switch to shut off the start windings.
That way I have something to test spinning things with. From there I will just install a rpm meter so I know how fast I am spinning things. I am going to try and put a dimmer switch on the low speed windings and see if I can adjust the rpms a little.
So, building test equipment with what is lying around.
-
My electric garden tractor after a model of a real tractor.
That's how I also want to build my windmill. A small working version of, for example, a Haliade or an Enercon.
-
Very nice. Do you have a estimate of the running time on the batteries ?
Cheers
Bruce S
-
So far we have only used the tractor for light jobs, and I have not had to charge the 4 Ah battery. I think the working time is an hour.
Now I can spend more time on wind energy again.
-
Plenty of great information in Adriaan Kragten's thread:
Design of a PM generator for a wind turbine.
It inspires to make a new test setup.
-
The yaw bearing.
The top of the mast consists of 2 hardened steel rings of scrapped bearings.
I want to drive the pivot at about 1 revolution per minute.
Maximum 2 turns clockwise and 2 turns counterclockwise.
Then there is no uncontrolled cable twist.
-
Not much space in the nacelle, so I want to drive the yaw bearing from below in the mast.
-
The cable goes through the slots and then 2x around the greased yaw bearing pivot.
Via the guides to the bottom of the mast.
I intend to finish the guides nicely so no moisture can get in.
-
The simple cable drum which I will mount in the bottom of the mast to operate the yaw bearing.
-
With spring pressure I can give the yaw bearing more than enough torque.
-
To drive the drum I have a 12 V motor with gearbox from a drilling - screwing machine.
This drives a worm and the worm gear on the cable drum at a very low speed.
The worm gear prevents the torque of the yaw bearing moving the drum.
-
First I now want to continue with the axial generator.
If both magnet rings are already mounted on the main bearing I can turn them nicely in 1 clamping.
Just on the right in-between size.
Then the gap between the magnets and the lamination cores in the coils can become thinner.
The solid auxiliary shaft I can remove later.
-
Here the magnet rings are mounted for a lamination package and a coil height of 13 mm.
-
Have you decided on the magnets you will be using?
Bruce S
-
For this test set up I intend to glue 20 magnets 10 x 4 ( thickness 2 mm ) on each magnet ring.
And in the stator 18 coils with lamination core.
-
With this main shaft I have 8 mm bore. The whole blade adjustment mechanism sticks out in front of the axis.
With a new main shaft with a larger bore I can mount the mechanism inside the shaft.
-
I wondering what output you are looking for?
Cheers
Bruce S
-
The idea is to make a test stand as complete as possible.
Driven yaw bearing, axial generator, active blade pitching, etc.
Output: for example aiming for 50 Watt at 30 rpm.
-
This axle and hub are more suitable with 20mm bore in the shaft to guide the actuation mechanism of the pitch control.
2 raceway grooves with 40 mm spacing, and each containing 17 x 6.4mm balls.
Magnet rings 104 mm outer diameter.
-
I noticed the 12 jack screws. How are they held in place? Are the holes bottom tapped ? with the screws held in with a locking glue?
Once again nice machining!!
Bruce S
-
@Bruce S
You are right. Once the stator is mounted, the bolt heads are difficult to reach.
So for the final assembly I'd better secure them with a drop of glue.
Detail of the (triangular) hub.
-
Due to low weight ( but in mind the necessary stiffness ) I assembled the spokes and the ring of the stator bracket out of thin steel sheet.
-
The composition can now be mounted on the yaw bearing.
First I want to make the blade pitch mechanism.
-
Bracket for mounting the stator bracket ( and bolted to it the main bearing ) on the yaw bearing.
My intention is to shape all parts in a way that scaling up and reinforcing is easy to do.
-
Did you bend a c-channel into a nice bow shape? Impressive.
-
@MattM,
It is for the connection of the nacelle hood to the statorbracket.
-
Stretching metal is an art. Unless someone has tried it, its hard to appreciate the skill. I know it is not easy to keep it in a nice uniform shape.
-
Bracket for mounting the stator bracket ( and bolted to it the main bearing ) on the yaw bearing.
My intention is to shape all parts in a way that scaling up and reinforcing is easy to do.
I'd expect enormous bending forces on those side braces. Have you considered making them about twice as wide (continuing up and back twice as far)? I'd think that would at least quadruple the strength.
(Adding a diagonal from the top to the rear would also add a lot of strength, but it looks like
it would get in the way of something - at least the rear bolts..)
-
A new lighter and wider version of the driven yaw bearing. Made of 1 and 2 mm sheet steel.
-
For U.S. folks its 18 gauge for 1mm and 12 gauge for 2mm.
-
As the basis for the yaw bearing the top 16.69 inches of the mast.
-
A layer of polyester around the mast and yaw bearing also provides protection against the weather.
I want a tilting mast, so I aim for lightweight above the tilting point.
-
My axial version of Reply # 524 is too small.
On this new shaft I want to mount magnet rings with a diameter of 150 mm.
-
Is it me? or does the latest picture look like the axial is broken?
Bruce S
-
@ Bruce S,
The shaft and hub are still in raw condition here, and I still have to weld the mounting for the magnet rings on it.
I am now making a mold for assembling the 2 magnet rings.
[attach=1]
-
The magnet rings must become 20 mm wide and 170 mm outer diameter.
It's about making them identical, tight and lightweight, and that's why this mold.
[attach=1]
-
Each assembled magnet ring tube will consist of 3 rings of 1 mm thick
and 1 ring of 2 mm thick. Against that ring I want to glue the 5 mm thick magnets.
[attach=1]
-
The new stator will have a nominal diameter of about 150 mm
I want to stick to Felix Niessen's Bavaria Winding Scheme Calculator.
27 coils with iron core and 30 magnets ( 20 x 5 x 5 )
[attach=1]
-
Inspired by the professional windmills around, the idea is that I first need to create test setups,
to, together with windmill builders on this forum, search for a design of a light direct drive generator with operational reliability.
In doing so we must be able to build that generator with stuff that is common and easy available for me and windmill friends on the forum.
It seems to me that the generator is the most difficult component.
I am also on a mission to create a working turbine that actually does something.
In my, now more than 1 year, oddesy I am left to believe the first step is to focus on the turbine. And then match the aternator to go with it.
I made the blunder of first spending time on designing the sickest alternator ever. Only to learn later that there is no turbine that can deal with it ;)
But since you and I both are from the low lands. May I please ask what is your typical wind speed where you want to harvest from?
Here it is in the 3m/s range. But since I have a somewhat large lake adjacent to my lawn and if winds are from the north then things can get a bit brutal.
-
@ Brandnewb,
Since the beginning I've been following your thread.
I have an average of 5 m/sec here, but you can also harvest energy from 3 m/sec.
Let's talk about the possibilities.
[attach=1]
-
Magnet rings and main bearing.
-
In between a setup for a smaller driven yaw bearing for a profile work piece.
The hub with hardened steel rings and an outer diameter of 72 mm
-
On the right the 1 degree conical mast top part of 20 cm long.
On the left the yaw bearing with the cuff that fits on this top part.
I'm going to cover the outside with polyester.
[attach=1]
-
@ Brandnewb,
Since the beginning I've been following your thread.
I have an average of 5 m/sec here, but you can also harvest energy from 3 m/sec.
Let's talk about the possibilities.
(Attachment Link)
Sorry @mbouwer, I have missed the email notifying me of your response.
I am ready to talk more details once I have my prototype turbine spinning for some time. earlier tests have been done but not too confidently yet.
THe image you posted is of a rather large / high turbine. That is something my municipality will never allow for though.
I'll keep one updated once more trustworthy results come in after my holiday.
-
Small main bearing for the new set up.
Largest diameter is 80 mm
[attach=1]
-
The blade suspension pitch bearings:
I think they should be part of the blade root.
And no moisture should get in.
I want to start with hardened steel rings ( 55 mm inner diameter ) of a scrapped bearing.
[attach=1]
-
Components for the blade shafts.
The blade must be able to make about 90 degrees of rotation suspended in the slide bearing and the ball bearing.
[attach=1]
-
The blade shafts. A layer of slidingbearing material is welded on the cuffs.
The right cuff jhas already been turned to 55 mm diameter with the correct fit in the hardened bearing rings.
[attach=1]
-
Basically for the blade suspension I am making large diameter light versions of a king shaft.
[attach=1]
-
My intention is to cover the blade suspension completely and to shield it as much as possible from the weather conditions.
[attach=1]
-
Scalable lightweight blade shafts.
I will now make a smaller version for the profile workpiece.
[attach=1]
-
To keep the moisture out, I want two O - rings per axle in the slide bearings.
[attach=1]
-
For the workpiece a light version of a main bearing.
[attach=1]
-
The quality of your casts has gone up considerably from the beginning. Very nice looking.
-
Prefabrication of the top section of the conical mast from concave strong steel binding tape 16 x 1 mm
[attach=1]
-
The top section of the mast. Now I can put the yaw bearing on it and fasten the main bearing.
[attach=1]
-
25 kg iron on the foot for stabilization.
[attach=1]
-
The yaw bearing sits with a conical fit on the mast. Now the main bearing suspension.
[attach=1]
-
Stifened rear magnet ring. Outside diameter 170 mm.
A light weight tube made of 1 and 2 mm sheet steel.
[attach=1]
-
With fixing ring. 522 grams.
My intention is to glue 30 magnets 20 x 10 and 5 mm thickness on it.
[attach=1]
-
To compose the iron cores in my 27 coils, I'm now cutting these teeth out of the lamination package of a discarded three-phase motor.
The distance between the magnets should then become 13 + 1 mm.
[attach=1]
-
From experience with making the stator with 45 coils (page 3 of this topic) and gluing the magnets I know that it is better to save that for later.
Therefore I will first continue with the blade suspension.
[attach=1]
-
Yaw bearing, main shaft and rear magnet ring assembled on the lattice mast (I will cover the mast with polyester)
Front magnet ring positioned with 24 mm spacing.
I now want to continue with the blade suspension.
[attach=1]
-
Around us we see more and more windmills and they all have blade adjustment.
I'd like to discuss some thoughts on that.
[attach=1]
-
I admire your persistence mbouwer, and you fabrication skills. I've shared in the past that I am not a fan of variable-pitch designs for small-scale turbines due to the complexity that it adds, but you may get someone else here that has interest. Best, ~ks
-
Several windmill friends here on this forum manage to use wind energy.
It inspires me to think about the use of blade adjustment as I see in professional windmills.
[attach=1]
-
I wonder how midwoud1’s turbine is doing. He had had a pretty nicely designed and executed turbine with variable-pitch.
-
As far as I know Midwoud has temporarily put away his turbine.
This is one of his ball bearing blade suspensions.
[attach=1]
-
I am amazed with his casted parts.
-
https://www.otherpower.com/otherpower_wind_tips.html
I'm working on the graphics at the top of the page with solidworks 2000 want to republish them.
-
https://www.fieldlines.com/index.php/topic,145700.msg996793.html#msg996793
see there there
-
The professionals bolt the blades onto a slewing ring.
But I don't think that's an option for small windturbines.
[attach=1]
-
A "small" 6 inch slewing ring runs around $1k... I need one for the 10ghz eme dish project
-
slewing ring as in a crossed roller bearing?
https://www.ebay.com/itm/134125057078 100 mm ID x 116 mm OD x 8 mm WD
NRXT15025 Crossed Roller Bearing 150x210x25mm
https://www.ebay.com/itm/193821862458
-
Thanks for the information. The bearing should be about 50 mm in diameter here.
I now want to try to make a lightweight rubber bearing.
With pieces of a poly-v belt as insert.
[attach=1]
-
a pilow block mounted ball bearing of 60mm bore size cost around usd 9 by piece in china. [attach=1] i know that, because i bought 40 pieces two mount before.
And that kind of bearings are designed to hold forces in the two axis, radial and axial. i dont know his price in USA.
-
@Leviatan,
What I'm thinking of is a 50mm outside diameter bearing for a blade bearing.
(The blade only needs to turn 90 degrees)
With as little iron as possible because otherwise it becomes much too heavy.
Weight is a scourge for a windmill.
[attach=1]
-
slewing ring as in a crossed roller bearing?
https://www.ebay.com/itm/134125057078 100 mm ID x 116 mm OD x 8 mm WD
NRXT15025 Crossed Roller Bearing 150x210x25mm
https://www.ebay.com/itm/193821862458
Good point, I was thinking a slew drive with motors...
(https://img1.wsimg.com/isteam/ip/ab3a8982-0afe-47fb-a792-728b9968d434/IMG_20190516_152743.jpg)
-
The blade shaft and hub with the rubber bearing (373 grams)
The shaft is supported in the nut and in the rubber ring (54 mm inside diameter)
to be able to turn its 90 degrees.
[attach=1]
-
Now that I have attached the contours of the blade root to the blade axle, it is also possible to mount a wooden blade.
I will fill the root with 2 component foam, shape it with sandpaper and then a thin layer of polyester.
[attach=1]
-
For now I want to make this set up with 1 blade.
[attach=1]
-
Blade head with 1 blade hub.
[attach=1]
-
Connection bracket between the yaw bearing and the main shaft.
[attach=1]
-
The contours of the blade filled with construction foam. Now I can cut off the excess and then sand it.
[attach=1]
-
The parts brought together on the top of the mast.
I'm now shaping a counterweight opposite the blade.
[attach=1]
-
The tripod for the blade-counterweight.
[attach=1]
-
Tripod and blade counterweight (1086 grams)
The layer of polyester will make the blade a little heavier and then I will have to add a little iron to the counterweight for balance.
[attach=1]
-
For less weight it would be much nicer to make a carbon-epoxy version of the blade.
[attach=1]
-
How do you bake the carbon if you are using foam?
-
When you work with carbon fiber mat you use epoxy to seal it. Its real similar to working with fiberglass but lighter.
-
Driven yaw bearing, main shaft with magnet rings, blade suspension and adjustment.
This test set-up again gives me better understanding of how to make the various components.
And can reproduce in case a windmillfriend wants to build along with me.
[attach=1]
-
Now I would like to make an 150 mm improved version of my axial.
Designing a generator is not my area of expertise, so I will definitely need some help.
[attach=1]
-
Just finished the mold for stacking and gluing laminations for the 27 coil cores (thickness 20mm)
[attach=1]
-
Today a friend gave me this Sparta bicycle motor and the intention is to turn it into a windmill generator.
[attach=1]
-
Excellent!
That could be a big step forward for your projects.
-
As a start I'm going to try to shape a usable main axis.
[attach=1]
-
NICE!!
With 24 coils , how shall you be configuring it?
Cheers
Bruce S
-
Thanks for your optimism, but I don't think I will be able to make a suitable windmill generator out of this for the time being.
[attach=1]
-
The 27 glued packages for the axial.
I expect more from this.
[attach=1]
-
A discussion about a generator for a small windmill will eventually always bring us the same answer:
"Look around at all those examples with their specially designed direct drive generators.
Always realized through cooperation of different disciplines".
-
Today a friend gave me this Sparta bicycle motor and the intention is to turn it into a windmill generator.
(Attachment Link)
If you count the number of magnets you get 20, so there are ten north poles and ten south poles. If you count the number of coils you get twentyfour. So the ratio is 24/20 = 6/5. These different numbers are chosen to prevent a high peak in the cogging torque but I doubt if this is effective enough to use this motor as a generator for a wind turbine. The angle in between the magnet poles of the armature is 360/20 = 18°. The angle in between the stator poles is 360/24 = 15°. So the difference is 3°. This means that you will get 360/3 = 120 preference positions per revolution. This isn't a high number and therefore the preference positions will be rather strong. These rather strong preference positions won't be a problem for a bicycle motor but it may give your wind turbine a rather high starting wind speed.
You must know very well what you are doing if you want to use this motor as a generator and if you use the original winding or if you make a new one. The winding must be a 3-phase winding. This means that there are 8 coils of phase U, 8 coils of phase V and 8 coils of phase W. I assume that the coil sequence is: U1, U2, V1, V2, W1, W2, U3, U4, V3, V4, W3, W4, U5, U6, V5, V6, W5, W6, U7, U8, V7, V8, W7, W8 right hand. So every phase has four coil bundles of each two coils. I assume that the sequence of the magnets is: N1, S1, N2, S2, N3, S3, N4, S4, N5, S5, N6, S6, N7, S7, N8, S8 right hand.
Next you should make a picture of the armature and the stator and in this picture you should take coil U1 opposite to magnet N1. If coil U1 is opposite to magnet N1, coil U2 is about opposite to magnet S1 (with 3° shift). This means that the winding direction of the two coils of one coil bundle must be opposite to make that the voltage generated in coil U1 is strengthened by the voltage generated in coil U2. Assume that coil U1 is wound right hand. So coil U2 must be wound left hand.
In the picture you can see that if magnet N1 is opposite to coil U1, magnet N6 is opposite to coil U5 and that magnet S6 is about opposite to coil U6. So coil U5 has to be wound right hand and coils U6 has to be wound left hand. So the winding direction of two opposite coil bundles is the same!
In the picture you can see that if magnet N1 is opposite to coil U1, magnet S3 is opposite to coil U3 and that magnet N4 is about opposite to coil U4. So now a south pole is opposite to the left coil of a coil bundle. This means that coil U3 must be wound left hand and that coil U4 must be wound right hand. The same counts for the opposite coils U7 and U8. So the winding direction of these four coils of phase U is just opposite as the winding direction of the first four coils of phase U! So it is very important to make no mistake in the winding direction of the eight coils of one phase.
The eight coils of phase V and the eight coils of phase W have the same pattern for the winding direction. It is easy to prove that there is a phase angle of 120° in between the coils of phase U, V and W. However, the coil patterns have to be positioned such with respect to each other that there is an angle of 12° in between a coil of phase V and a north pole and an angle of 24° in between a coil of phase W and a north pole. This is the case for coil V3 and pole N4 and for coil W5 and pole N7. So these two coils must be wound right hand just as coil U1. The mechanical angle in between coils U1, V3 and W5 is 120°. Assume right hand is R and left hand is L. So the sequence of the coil number and the winding direction is: U1R, U2L, V1L, V2R, W1R, W2L, U3L, U4R, V3R, V4L, W3L, W4R, U5R, U6L, V5L, V6R, W5R, W6L, U7L, U8R, V7R, V8L, W7L, W8R.
The armature has the same magnetic position with respect to the stator if it has rotated 36°. So a rotational angle beta = 36° corresponds to a phase angle alpha = 360°. So a rotational angle beta = 1° corresponds to a phase angle alpha = 10°. So a rotational angle beta = 3° corresponds to a phase angle alpha = 30°. This means that there is a phase angle of 30° in between the voltages generated in coil U1 and coil U2. Adding two identical sinusoidal voltages which are out of phase results in a new sinusoidal voltage which has a maximum if the magnet N1 has rotated 1.5° right hand from the drawn position in the figure. Beta = 1.5° corresponds to alpha = 15°. This results in a summerised maximum voltage of 2 * sin 75° * Vmax = 1.932 * Vmax. If both voltages would be in phase, the maximum voltage would be 2 * Vmax if Vmax is the maximum voltage of one coil. The fact that the voltages are 30° out of phase, results therefore in a reduction of the voltage by a factor 1.932 / 2 = 0.966 which is certainly acceptable.
If a new winding is laid, the number of turns per coil and the wire thickness can be found by try and error for a certain wind turbine rotor. However, I see no good reason why you should rewind the stator if the winding direction of the coils is as I predicted.
-
the only reason to rewind that core would have been to change the voltage. already its going to be pretty optimal for the intended purpose.
you could add more copper if there is room.
sometimes it is beneficial to wind every other tooth of the core, but in this case, winding every tooth has better thermal conduction from the windings to the core, and more surface area for cooling.
those did look like bread loaf magnets so the cogging torque was probably rather small.
-
the only reason to rewind that core would have been to change the voltage. already its going to be pretty optimal for the intended purpose.
I would never rewind the stator as with the standard winding, you have three different voltages depending on how the coil bundles of one phase are connected. The two coils of one coil bundle must always be connected in series because in parallel connection of coils which are out of phase with each other results in an internal short-circuit current! If all four coil bundles of one phase are connected in series, you have the highest voltage and the lowest current at a certain rpm. If two coil bundles, connected in series, are connected in parallel to two other coil bundles, connected in series, the voltage halves and the current doubles. If four coil bundles, connected in series, are connected in parallel to four other coil bundles, connected in series, the voltage halves and the current doubles again. Another advantage of the standard winding is that it is wound by a machine and that therefore all wires are lying very close to each other. You will never get such a nice winding if you wind the coils by hand.
-
It seems to me that there are not many windmill friends here who want to build a small windmill themselves and that is why it was so nice that a friend came up with the idea to try to turn that Sparta motor into a windmill generator.
But in my opinion it is much better to continue building an axial.
[attach=1]
-
Given my setups, I believe I'm now at the point where building the components for a small windmill is doable.
The mechanical components are light, inexpensive and scalable.
The next step: the electrical design of the axial generator,
is definitely not my area of expertise.
That is why I would like to work together with a student ( profile assignment )
[attach=1]
-
Today a friend gave me this Sparta bicycle motor and the intention is to turn it into a windmill generator.
(Attachment Link)
I have tried if I could find more information about this motor and I found the Dutch YouTube films: "Sparta Ion GD Design" and "Sparta ion E Bike hubmotor, display, accu hack, controller swap". I think that this motor can be used as generator of a small wind turbine if the inside electronics are removed or simply no longer used. Only the three big phase wires are used and connected to a 3-phase rectifier for battery charging. As I have explained in my earlier post, this generator will have 120 preference positions and so the rotor of the wind turbine must have a rather high starting torque coefficient to get a sufficiently low starting wind speed. I have designed such a rotor for the 28-pole, 1-phase Nexus hub dynamo. This VIRYA-1.04 windmill is described in a manual which can be found at the bottom of the list with KD-reports on my website. I think that this rotor can be scaled up to a diameter of maximal 2 m for this much bigger Sparta motor. The VIRYA-1.04 head should also be scaled up to get a proper working safety system.
Sparta is a Dutch bicycle brand and it might be that such motors can only be found in The Netherlands but it might be that one can find a similar front or back wheel motor of other brands in other parts of the world. If one has found such a motor, one should first measure it with the original winding for a 12 V battery load to find the Pmech-n curve because with this curve it can be checked if the generator matches with the optimum cubic line of the chosen wind turbine rotor. One can vary the rotor diameter and the design tip speed ratio to get optimal matching. The formula for the optimum cubic line is given as formula 8.1 of my public report KD 35.
-
Don't you also find it much more fascinating to think about a self-built axial generator?
-
Don't you also find it much more fascinating to think about a self-built axial generator?
I have designed and built several PM-generators but not because it is more fascinating than buying one. Most PM-generators which you can buy have disadvantages which make that use in a wind turbine is difficult or even impossible.
One of the disadavantages of most PM-generators which have iron in the coils, is that they have a rather large peak in the cogging torque resulting in a high starting wind speed if a rotor with a low starting torque coefficient is used. It is possible to design a PM-generator with iron in the coils and with a low peak in the cogging torque if there is only a difference of two in between the number of armature and stator poles (see public report KD 580).
Another disadvantage of most PM-generators which you can buy is that a too high rotational speed is needed if the generator is used for 24 V battery charging. If you make the generator yourself, you can chose the winding and so you can change the voltage at a certain rpm such that the matching with a certain wind turbine rotor is optimal. But building of only one generator will be much more expensive than buying a generator which is mass produced.
Another disadvantage of most PM-generators which you can buy is that mostly no measured Pmech-n and Pel-n curves are given. Sometimes the characteristics for a resistance load are given but these characteristics are completely different as for a battery load. So if you buy such a generator, you have to measure the wanted characteristics yourself and if the result is not what you need for the wanted rotor of the wind turbine, the whole purchase is a waste of money.
The Sparta wheel motor which we discussed earlier, has 20 armature poles and 24 coils resulting in 120 preference postions per revolution. If they would have used 22 poles in stead of 20 poles, the difference in pole angle would have been 1.3636° resulting in 264 preference positions per revolution. Such a motor would be much better for a wind turbine generator. If they would have used 26 poles in stead of 20 poles, the difference in pole angle would have been 1.1538° resulting in 312 preference positions per revolution. Such a motor would even be better for a wind turbine generator than a 22-pole motor. The winding would be different. Each phase must now have two bundles of four coils.
You can design an axial flux or a radial flux PM-generator. Each type has certain advantages and certain disadvantages. Although most people on this forum use axial flux generators with no iron in the coils, there are some very good arguments to chose for a radial flux generator based on the housing and winding of an asynchronous 3-phase motor.
-
My idea is that problems and questions raised here have often long since been solved by the professional windmill builders. All we have to do is look around us to try to implement their solutions.
[attach=1]
-
Adriaan Kragten:
[Most PM-generators which you can buy have disadvantages which make that use in a wind turbine is difficult or even impossible.]
Based on what Adriaan writes I would like to put forward some examples.
Much more fun than continuing to search is building a generator yourself.
A good example is of course the booklet by Hugh Piggott.
[attach=1]
-
example 2
Adriaan writes:"One of the disadavantages of most PM-generators which have iron in the coils...."
Isn't it a big advantage for diy builders to have iron in the coils because you can then use much lighter magnets?
[attach=1]
-
example 3
...... disadvantage with iron in the coils, is that they have a rather large peak in the cogging torque resulting in a high starting wind speed ....
Another reason to diligently look for ways to apply active blade adjustment.
From the starting position you already have a large torque even with little wind.
[attach=1]
-
Here I thought the iron was simply to hold a complete circuit to prolong the life of the magnets. I've read the magnets separated by a distance - without a magnetic circuit completed - slowly lose their magnetism.
-
@MattM,
If so, we have another reason to put an iron core in the coils.
example 4
[ Building of only one generator will be much more expensive than buying a generator which is mass produced ]
With creativity building your own is less expensive.
But also it has often been said on this forum that suitable generators for small windmills are not for sale.
We need a design that can also be built in practice.
[attach=1]
-
MattM,
What is "slowly"? Is this something that happens over years, decades... Do you have a source that describes this in more detail? Thx, ~ks
-
example 2
Adriaan writes:"One of the disadavantages of most PM-generators which have iron in the coils...."
Isn't it a big advantage for diy builders to have iron in the coils because you can then use much lighter magnets?
(Attachment Link)
Yes, the advantage of having iron in the coils is that the air gap is much smaller and therefore you can use thinner and so cheaper magnets and still have a large flux density in the coil. But for use of magnets in a motor, a certain peak on the cogging torque isn't a problem and therefore designers of most PM-motors prevent this cogging only up to a rather high limit. But for a modern fast running rotor of a wind turbine, the starting torque coefficient is only about 10 % of the optimum torque coefficient and this results in a high starting wind speed if the peak on the cogging torque is too high. For a PM-generator with iron in the coils, one therefore has to pay more attention to the reduction of the peak on the cogging torque than for a PM-motor. But with the present high prices of neodymium magnets it becomes more and more important to reduce the magnet costs and then a well desiged PM-generator with iron in the coils is the cheapest option for a certain maximum torque level. I have compared PM-generators with and without iron in the coils in chapter 7 of my public report KD 341.
Neodymium magnets don't loose their remanence if they are not short-circuited by an iron loop. They can loose their magnetism if the temperature becomes too high. The temperature at which this starts to happen depends on the magnet quality. This critical temperature will normally not be reached in a PM-generator of a small wind turbine, even not if the generator is short-circuited. I have measured PM-generators for short-circuit for which you have the largest counter acting magnetic field and they didn't become weaker.
-
@Adriaan Kragten,
So it's about making the best possible combination of magnet, lamellar package and coil.
example 5
[ .....So if you buy a generator, you have to measure the characteristics yourself..... ]
Building your own generator involves testing.
[attach=1]
-
MattM,
What is "slowly"? Is this something that happens over years, decades... Do you have a source that describes this in more detail? Thx, ~ks
Sadly there is no formula I could find. Magnets in a perfect state should lose 1% of their strength naturally every century is the only specific statistic I could find. Heat, kinetic collisions, and being exposed to opposing (or dissimilar) magnetic fields are the ways magnets quickly lose charge, but even then the data tends to be specific to a magnet's material properties. The last one would be like putting a neo against a ferrous-ceramic magnet, the latter will almost instantly begin to lose its field.
-
@MattM,
But also it has often been said on this forum that suitable generators for small windmills are not for sale.
(Attachment Link)
That isn't true. The Chinese company Hefei Top Grand supplies a large range of well designed axial flux PM-generators with no iron in the coils which can very well be used in a small wind turbine. I have designed several VIRYA wind turbines which make use of such a generator (see list with KD-reports on my website). I have even bought a small one and measured it (see report KD 595). But the characteristic of these generators is only given for a fixed resistance as load and this characteristic differs strongly from the characteristic of a battery load or of a load which is gained if the windmill is grid connected by an inverter. In all my KD-reports in which generators of Hefei Top Grand are used, I give a method how to derive the wanted characteristic for a battery load or for grid connection from the measured characteristic for a resistance load. I have advised Hefei Top Grand to measure their generators differently because no one is dissipating the generated power in a resistor but they don't respond to this advise. But many other Chinese suppliers of PM-generators give no measured characteristics at all. So measurements for a resistance load at least give some information.
-
I think the only other consideration with pre-manufactured unit is what the characteristics and quality of bearings are. The ones I've seen are compact and nicely packaged, but I'm not sure how robust the bearings and castings/hubs that support them - probably fine if it is a geared, or chain-driven application where the loading is radial. Most of the home-built axial's employ heavier, tapered roller bearings which can be sized to meet the rotor loading.
I suppose it could be coupled to the rotor, which is in-turn separately supported, but that adds components, cost and complexity; always trade-offs.
-
I think the only other consideration with pre-manufactured unit is what the characteristics and quality of bearings are. The ones I've seen are compact and nicely packaged, but I'm not sure how robust the bearings and castings/hubs that support them - probably fine if it is a geared, or chain-driven application where the loading is radial. Most of the home-built axial's employ heavier, tapered roller bearings which can be sized to meet the rotor loading.
I suppose it could be coupled to the rotor, which is in-turn separately supported, but that adds components, cost and complexity; always trade-offs.
The direct drive generators of Hefei Top Grand have a rather large shaft diameter in relation to the outside diameter of the generator and therefore also rather large bearings. This is because the shaft is hollow as the cables are guided through this central hole. The whole housing is rotating. Sealed ball bearings are used for the smaller sizes which are running very light. There is a possibilty to add an extra oil seal at the shaft side which I have done for my generator. The generator housing is completely closed, so no water or dust can come in contact with the magnets or with the coils. The generator type TGET165-0.15kW-500R which I have tested in 2015 is used in combination with a 2-bladed and later with a 3-bladed stainless steel rotor from about 2017 up to now. So it is running for about six years now without any maintenance. This clearly shows the quality of this brand. But obtaining one directly from China is rather expensive. The price off factory is more than doubled because of costs of transport and import taxes. Exact values are given in KD 595. But the costs can be reduced significantly if larger quantities are ordered. But you must always start with one protype and first measure one generator to check the matching in between rotor and generator for the correct load.
There are countries in Africa and South America where one wants to start serial production of small wind turbines and then it is very easy if a high quality direct drive PM-generator can be bought. The generator is certainly the most complex component of a small wind turbine. Building the generator yourself is nice if you don't count the spent time. But for commercial production, building the generator will take a large part of the time needed for the whole wind turbine. And all special components like magnets, glue, copper, bearings, seals etcetera have to be imported separately.
-
Reading al those posts on this forum with arguments
to chose for the housing and winding of an asynchronous 3-phase motor
or to chose all kinds of other stuff as a starting point for a windmill generator
Isn't it logical then drawing the following conclusion?
You better build a Piggott generator according the booklet.
Or the innovative way: trying to find cooperation with other disciplines to build an axial generator with iron in the coils.
[attach=1]
-
I dun'no mbouwer, I tend to think Hugh was quite the innovator, proposing new ideas for small- scale turbines that could be constructed with basic materials, skills and relatively simple tools and equipment.
I'm not sure that what is best for a large-scale wind farm, where a maintenance crew and a crane are on site to rotate through set interval, pre-emptive component replacements and repairs is also the best fit for the backyard enthusiast found here. Still, I applaud your persistence and I respect an approach that is different from my own.
Regarding the premanufactured units from China, I think I'd need to see more than this Adriaan. It sounds like you had good luck, but this is one 150-watt unit, on how high a tower, in what sort of wind regime? This broad endorsement of quality doesn't sound quite as scientific as what we've come to expect from you.
-
@Kitestrings,
We should certainly also appreciate that we can piggyback on what you as precursors are showing us.
[attach=1]
-
Regarding the premanufactured units from China, I think I'd need to see more than this Adriaan. It sounds like you had good luck, but this is one 150-watt unit, on how high a tower, in what sort of wind regime? This broad endorsement of quality doesn't sound quite as scientific as what we've come to expect from you.
In have tested the one as described in KD 595 on a 14 m high tower in the Dutch inland wind regime for six years now. The wind turbine was never stopped, not even during the very heavy storms which we have had. It is even not possible to stop the rotor by making short-circuit close to the dump load because the rotor torque is too high at high wind speeds. So during heavy storms the rotor was turning rather fast with a short-circuited generator but this didn't result in burning of the winding! This demonstrates the effectiveness of the hinged side vane safety system but also the strength of the generator shaft and bearings and the cooling capacity of the stator winding. All generators of Hefei Top Grand type TGET are designed in the same way so with a rotating closed housing. So this aspect of the quality, that the housing is closed, is the same for all types.
I don't like the open housing of the axial flux generators as designed by Hugh Piggott because the magnets and the coils can become wet or durty and the iron sheets can rust. It is an acceptable design if you want to build a generator yourself but concerning quality, this choice can be doubted. I have heard of terrible designs of other Chinese manufactures but to my opinion, Hefei Top Grand is a positive exception and I don't get paid to tell this. But the only way to be sure if you need a bigger one than the one which I have used, is to buy one and test it on a test rig to measure the characteristics and to test it in a real wind turbine to verify the quality. I can't measure a bigger one because my test rig isn't strong enough. I won't build a bigger wind turbine with such a generator because coming week I become 76 and so the life phase of building things is over. I think that I have done enough by writing the design reports (see KD 614, KD 669, KD 705, KD 707, KD 715, KD 717, KD 732 and KD 738).
-
Today a friend gave me this Sparta bicycle motor and the intention is to turn it into a windmill generator.
(Attachment Link)
I have found another Dutch film on YouTube about this Sparta wheel motor. The title of this film is "Sparta Ion GD Design". In this film it is shown that the inverter which transforms the DC current coming from the battery into a 3-hase current with variable frequency, is soldered at one of the two printed circuit boards which are mounted inside the motor. Both printed circuit boards have to be removed to get acces to the three terminals to which the 3-phase wiring is connected. The three terminals have internal thread M4 or M5 and are situated at the bottom of the aluminium housing. So if one wants to use this motor as a generator, dismantling of the motor is required to remove the two printed circuit boards and to connect a new 3-phase wire to the three terminals. The generated 3-phase current can then be rectified to get a DC current.
The nominal battery voltage as motor is 24 V and so I expect that you wil get a rather high DC voltage at a rater low rpm. Therefore it might be possible to use this modified motor for 12 V or 24 V battery charging if the windmill rotor is chosen such that the matching is acceptabel for one of the two nominal DC voltages.
-
Such motors can be used as a generator, but the body diode of the mosfets will drop as much as 10 times as much voltage (watts) as the board was designed for.
The advantage of retaining the motor controller as a rectifier is that you can pwm the lower 3 mosfets in parallel as one switch, to make a boost converter for extracting all the wasted low wind energy.
-
Such motors can be used as a generator, but the body diode of the mosfets will drop as much as 10 times as much voltage (watts) as the board was designed for.
The advantage of retaining the motor controller as a rectifier is that you can pwm the lower 3 mosfets in parallel as one switch, to make a boost converter for extracting all the wasted low wind energy.
The electronics in this motor don't allow the transformation of the generated AC power into DC power. There are a few electric bikes which work this way and which put the braking power back into the battery but most of them don't. So if you spin the housing, you will measure no DC voltage at the two main cables which are normally connected to the battery. May be you can modify the printed circuit board or use components out of it but then you must know what you are doing. The current electronics of the inverter and the frequency regulator are very complicated. It is much easier to remove all the electronics from the motor and use a new 3-phase cable and a new 3-phase rectifier which can have a sufficient high current. There is not enough power in low wind speeds to do a lot of effort to generate this power.
-
interesting, all the cheap ones i know of are just 6 mosfets.
it might have a bi directional switch on the dc bus to prevent blowing up the battery pack if its connected backwards. ..
-
interesting, all the cheap ones i know of are just 6 mosfets.
it might have a bi directional switch on the dc bus to prevent blowing up the battery pack if its connected backwards. ..
If you look in the film I refered to, you can see that there are six identical components on one of the printed circuit boards mounted at a triangle. For me, these componens look like transistors but it might be mosfets. These six components must be a part of the inverter. But this doesn't mean that the other components are designed such that the AC current can be transformed into DC current. Using the braking power to charge the batteries is mainly important for countries with hills as then the battery is charged when you go down the hill. I have heard of a (rather expensive) Swiss bicycle brand which works that way. But in most of The Netherlands, we don't have hills and generating the braking power when you stop for a traffic light isn't worth the effort.
-
I've seen many projects inspired by Hugh that integrated rain guards. Nothing prevents a person from sealing off their Piggott-style stators and magnets. They are already sealed by design, so the shrouds are purely aesthetic. That they are somehow exposed to weather is a flaw is an odd argument.
-
For windmillfriends who want to protect axial generators, like a Piggott, against weather influences I shaped a polyester set up of a cover.
[attach=1]
-
I've seen many projects inspired by Hugh that integrated rain guards. Nothing prevents a person from sealing off their Piggott-style stators and magnets. They are already sealed by design, so the shrouds are purely aesthetic. That they are somehow exposed to weather is a flaw is an odd argument.
I have the book "A Wind Turbine Recipe Book: of Hugh Piggott. On the front page of this book there is a photo of the whole wind turbine and the generator construction is clearly visable. On this photo you can see that the generator consists of two steel armature disks with the magnets glued at the inside and that the stator with coils is mounted in between the two armature disks. The stator is supported by three threaded rods and nuts at each side of the stator which have to be adjusted such that the stator is just in the middle of the air gap in between the magnets. If this adjustment is not done properly, the stator will touch the magnets. Touching can also be caused by the gyroscopic moment which results in some bending of all the generator components. This requires that the air gap at both sides of the stator must be rather large. Correct mounting of the stator requires adjustment which is a weak point. So this generator is certainly not sealed by design. Water and dust can enter it from all sides. In the past I have been contacted by companies in India and Africa which have built Hughs design and they didn't like the generator just because of the points which I mentioned. Hugh Piggott did very well by spreading his knowledge for a low price but this doesn't mean that his designs have no weak points and that it is unfair to mention these points.
The stator of the axial flux generators of Hefei Top Grand is directly connected to the shaft and the cables are guided through a central hole in this shaft. Both magnet disks can therefore be bolted together at the outside making the housing completely closed and much stiffer. Stiffness is important as the rotor is directly mounted to the housing. Technically this is a much better solution but it requires acurate casting and machining of all componets and that is only possible for well equipped factories.
So there is certainly a market for Hughs simple designs which can be made with only simple tools. I have designed an axial flux generator with only one armature sheet and using a front wheel hub of a bicycle (see KD 679) for the VIRYA-1 rotor. This generator is even simpler than Hughs generators but it needs heavy magnets and it is also not closed.
-
Do you mean both " magnet disks" instead of "stator disks"?
[attach=1]
-
I think Adriaan raises a valid concern here, though I would say it is not so much the "iron sheets" if this is to mean the magnet rotors, as it is the magnets themselves that must be protected. Neo's in particular are challenging to protect from corrosion especially where salt is an added influence. We are not in a coastal region, but still had an issue with several magnets some years back. I'd like to think we did better on our second attempt, but only time will tell.
In another book of Hugh's "Wind Power Workshop" he describes and illustrates 'Air Gap' Alternators including 'Case Driven' and 'Shaft Driven' versions. I think my copy is dated 1997, so nothing really new here. My point has not shifted, the rotor loading still must be carried by the bearings. They might have it right, but hard to know the design parameters that may have been considered; certainly not easily remedied if not.
What I like about Hugh's books is that he writes and articulates ideas in easily understandable language. I suspect this is at least one reason that they are popular. It allows someone to get a good start and a basic grasp the realm of considerations to be made. Trades offs of course.
-
Do you mean both " magnet disks" instead of "stator disks"?
(Attachment Link)
Yes, I have changed it.
There is a big difference if a person wants to build one wind turbine for himself or if a company wants to start serial manufacture and make a certain profit. If you make one wind turbine for yourself, you only count the used materials and not the spent time. If you get problems with the wind turbine, you are responsible yourself because you have built it. But if you want to start serial manufacture and sell the wind turbine for a reasonable price, the spent time becomes crucial and the quality must be that high that the wind turbine can turn at least five years without problems. Manufacture of the generator and the tapered wooden blades takes a lot of time for the wind turbines of Hugh Piggott.
But this isn't the biggest problem. The biggest problem is the safety system which must turn the rotor out of the wind at high wind speeds. It is chosen to use, what I call the inclined hinge main vane safety system. This system can work properly if the dimensions and weight of the vane and the eccentricity of the rotor are chosen correctly and if the bearings of the vane arm and the head have little friction. But this requires good sealed bearings running at a machined surface. Especially the vane arm bearings can give problems as it is simply a pipe running around another pipe with some grease in between. At hot days the grease becomes liquid and flows down. So after some years, the friction torque of these bearings can become very high making that the rotor is not turning out of the wind. This can result in broken rotor blades because of a too high thrust. If the hinges work properly, the rotor can turn out of the wind rather fast at strong wind gusts because the moment of inertia of the head around the tower axis is rather small. This causes a high gyroscopic moment in the rotor blades which alse can result in blade failure. Several people on this forum have reported broken blades and so this is a serious problem. If you are the manufacturer and if you have different clients with severe problems, your company won't live long.
-
Lot's of approaches mbouwer...
I tend to think wood is a really good material for small-scale turbines. It can be locally sourced, renewable and relatively easy to shape. Yes, quality has to be considered, but overall a pretty good choice. I worked for a wind manufacturer in the '80's that had begun production of wood blades on a CNC router/shaper of some sort, so it could definitely be scalable I'd say.
Side furling, or inclined hinge, is probably the most time-proven feature we can point to here. With minimal parts, minimal maintenance, and no outside controls it is elegant, simple and long-lasting.
-
To also be able to use a wooden blade I made this setup with a steel blade root (with bearings) so the blade can be attached to it.
Afterwards the root can be filled with foam and finished.
[attach=1]
-
I must be missing something in the argument about Hugh Piggot designs. He pushed for sealing the individual components to protect them from weathering. I remember him even recommending marine grade epoxy.
That is sealed by design.
-
I must be missing something in the argument about Hugh Piggot designs. He pushed for sealing the individual components to protect them from weathering. I remember him even recommending marine grade epoxy.
That is sealed by design.
You may call this sealed by design but I only call it sealed by design if all this tricks to protect the magnets, the glue, the iron sheets and the copper of the windings are not necessary because the whole generator housing is closed.
-
If you can properly preserve the generator parts, the big advantage is of course that the generator is well cooled by the wind.
[attach=1]
-
In the large mills with a radial generator, often the outer circumference of the stator (with cooling fins) is also the outer shell at the same time.
[attach=1]
-
A while ago I made a set up like that. If a windmill friend wants to continue with it, I can add a main shaft.
[attach=1]
-
When I make a new stator for the profile workpiece I also want to put cooling fins on the circumference of the axial generator.
[attach=1]
-
The cooling fins then form one piece with the stator and then cover the magnet rings and the width becomes about 2 inches ( thickness of the stator + 2 x the thickness of the magnet rings )
[attach=1]
-
Spring is coming and first I want to modify my electric tractor with a wide front axle.
[attach=1]
-
Why? Is it because of the possible instability of the narrow front wheels? We had a FarmAll that had a similar front wheel setup, we always steered it using both the front steering and split clutches. My guess is that being that it's now electric you don't have the ability to use the split clutches on the rear axle.
Nice looking tractor BTW
Bruce S
-
@Bruce S,
With a motor on each rear wheel, steering here is also as you describe.
But that is also possible with a wide front axle.
Now I want to make a 3-point front hitch and then a wide front axle suits it better.
[attach=1]
-
It would of course be great if I also succeeded in making a windmill in the garden with which I can charge the battery.
[attach=1]
-
I think it would be fun to make a profile paper / thesis together with a student.
[attach=1]
-
On the forum I see windmillfriends who have come to the point where they have built a small windmill and succeed to use the electricity. It feels so good that they've gotten so far that they don't feel the need to innovate.
But do they also think of us who also would love to use wind energy?.
We cannot build such a huge mast and enjoy climbing it every now and then.
We do not live on a vast plain with undisturbed wind.
We do not have an estate on the coast where we can shape and enjoy a 3 Piggotts park.
We can't buy a collection of Chinese stuff to experiment with.
What we can do is contact each other to brainstorm about a design:
----a nice piece of work in the garden
----with tilting mast which does not require a heavy foundation.
----a simple self-built axial generator.
----quietly rotating blades with safe blade adjustment.
I wonder if there are people on the forum who are interested in this.
Regards Rinus
-
A good question, I think.
But we also maybe need to understand motivation: would such a project be for satisfaction in its own right, or to save money or carbon?
For a typical urban site the latter seem unlikely given your criteria.
Rgds
Damon
-
In my opinion, we are at the stage of thinking together about a good diy design with all the features of safe turbines.
[attach=1]
-
A good question, I think.
But we also maybe need to understand motivation: would such a project be for satisfaction in its own right, or to save money or carbon?
For a typical urban site the latter seem unlikely given your criteria.
Rgds
Damon
Damon;
I'm now at the point where the unit I'm desperately trying to get approval from our city's building commission is one that kinda fills at least two of those.
I like building things and I think if I keep stuff from going to the landfill and will charge some LEDs on my umbrellas then I'm happier.
I think Rinus' ideas may be far more farther and larger than I could even get close to doing at this point.
Cheers
Bruce S
-
One of the options for a small and light diy mast is the segmented modular steel tower.
Then tack welding the segments and afterwards covering it with a layer of polyester.
[attach=1]
-
Modvion uses wooden prefabricated segments.
Diy we could also use wooden slats and then cover them.
[attach=1]
-
How tall are you proposing, and to hold how big of device?
-
A windmill friend collected scrapped stevedore binding material ( thickness 1 mm ) to shape a 5 meter conical tilting mast.
[attach=1]
-
The tower or other support structure is all that stands between you and a lawsuit f someone is injured or property is damaged when it comes down. Unless you know how to calculate the engineering specs I do not recommend home made towers... you have the payload wind loading, each tower section has wind loading... it is complicated math that gets worse the taller you go
-
The mast will be heavily overdimensioned and based on the different cross-sections it is possible to do calculations on it.
There is also not such a nasty load on the mast when there is a quietly running turbine on it with safe blade adjustment.
[attach=1]
-
The mast will be heavily overdimensioned and based on the different cross-sections it is possible to do calculations on it.
There is also not such a nasty load on the mast when there is a quietly running turbine on it with safe blade adjustment.
(Attachment Link)
Things fail, wind load climbs... not planning for it is not good practice. I always spec my towers for worst case conditions, 1 inch of ice and 60mph winds in winter, 100mph winds in summer
-
Agreed and that's also why it's so nice that we can share experiences on the forum.
Bottom view of the ring for the mast. Diameter 260 mm and 24 holes for bolts M 8
[attach=1]
-
The intention is a movable foundation. The steel discs weigh 10.4 kg each and the shafts are 40 mm in diameter.
Now I have to shape a frame where the discs are spaced far enough apart.
[attach=1]
-
Today a friend gave me this Sparta bicycle motor and the intention is to turn it into a windmill generator.
(Attachment Link)
If you count the number of magnets you get 20, so there are ten north poles and ten south poles. If you count the number of coils you get twentyfour. So the ratio is 24/20 = 6/5. These different numbers are chosen to prevent a high peak in the cogging torque but I doubt if this is effective enough to use this motor as a generator for a wind turbine. The angle in between the magnet poles of the armature is 360/20 = 18°. The angle in between the stator poles is 360/24 = 15°. So the difference is 3°. This means that you will get 360/3 = 120 preference positions per revolution. This isn't a high number and therefore the preference positions will be rather strong. These rather strong preference positions won't be a problem for a bicycle motor but it may give your wind turbine a rather high starting wind speed.
Today I have bought a similar motor (for only 20 euro) to see if it is possible to use it as a generator for a wind turbine with a rotor diameter of about 1.8 m. The first thing which I checked is the peak on the cogging torque. I measured a peak of about 0.6 Nm which is rather high. I found that the generator has 20 prefererence positions per revolution in stead of 120 which I don't understand if the armature has 20 poles and if the stator has 24 poles. I will open the housing and see if the internal construction is the same as that of the photo given by mbouwer. I will measure at least the open DC voltage for a certain rotational speed after making three new wires directly to the three phases and using a 3-phase rectifier. If possible on my existing test rig, I will also measure the torque and so the Pmech-n and the Pel-n curves for a 12 V battery load. My investigations will be published in a new KD-report if it appears that the generator is usefull for a certain rotor. The results will be mentioned in a separate post.
-
It strikes me that several windmill friends are getting excited about converting a bicycle engine to a windmill generator.
Perhaps someone knows an example where this has been achieved.
[attach=1]
-
The bicycle motor has an outside rotating drum with magnets.
If you want to start from a existing construction with magnets and coils, wouldn't it be easier to use a DC motor with an inside rotating rotor as a starting point?
[attach=1]
-
For a windmillfriend who wants to get started with a bicycle motor:
I still have one lying around and you can get it for free.
[attach=1]
-
For a windmillfriend who wants to get started with a bicycle motor:
I still have one lying around and you can get it for free.
(Attachment Link)
If that is the one from which you have removed the winding, it is useless. But anyone who will try this can better wait untill my experiments are finished. It is not only the generator which counts but one also has to design a rotor which can be connected to one of the generator flanges and it must have a sufficiently large starting torque coefficient.
-
The bicycle motor has an outside rotating drum with magnets.
If you want to start from a existing construction with magnets and coils, wouldn't it be easier to use a DC motor with an inside rotating rotor as a starting point?
(Attachment Link)
This isn't a DC motor but a permanent magnet 3-phase AC motor. One can use DC current to drive this motor if one uses a 3-phase inverter with variable frequency. What is the origin of this motor?
-
This motor is completely intact.
[attach=1]
-
The motor shown in Reply # 671 was part of a 36 volt battery powered electric wheelbarrow.
[attach=1]
-
When later on the windmill head is on this top part of the mast I can roll the assembly to a place with undisturbed wind for a test.
[attach=1]
-
This is a nice way to make the mast I think. Conical lattice with polyester covering.
It can be scaled up to the desired strength and dimensions.
[attach=1]
-
The blade suspension is light and strong and when I also cover it with polyester it is part of the blade.
I'm going to make 3 of them now.
[attach=1]
-
As far as the blade control is concerned, I think it would be best to build on the Midwoud design.
[attach=1]
-
Search for midwoud1 on this website and youtube if you do not understand mbouwer'sreference.
https://www.fieldlines.com/index.php?topic=148775.0
-
https://www.fieldlines.com/index.php/topic,145925.0.html
Reply #92 on page 4 of this topic shows a nice rotorhead test.
-
How much force is on those central gears? I wonder if 3D printing could make mass production affordable. If you could get by with plastic gears it becomes much more practical.
-
But the question is whether you really need those gears.
[attach=1]
-
This topic was split into "Re: axial generator with lamination core" -
2-axis solar tracker (https://www.fieldlines.com/index.php?topic=150773.0)
-
Nice test set-up: Vestas equipped with guyed blades.
[attach=1]
-
The guying of blades opens up possibilities to make the blade suspension so much lighter.
[attach=1]
-
Nice test set-up: Vestas equipped with guyed blades.
(Attachment Link)
Wonder if that is a construction jig to keep the blades form rotating and bringing the turbine live? Don't want fingers in high voltage by accident... or in moving parts!
-
Guying makes it possible to shape the blades longer and longer I think and to build turbines with more megawatts.
[attach=1]
-
Do you know how new and/or how many MW that turbine is?
Rgds
Damon
-
It is a standard V136 - 4.2 MW
But they now have their 15 MW and they may want even larger and bigger
[attach=1]
-
The guy wires look to me like a quick fix for an engineering fail. I could be wrong, but that's the way it looks to me.
-
All sorts of designs are made up to be able to make the blades longer.
Like here bushings in the blade root.
[attach=1]
-
[attach=1]
In Windpower Monthly Eize de Vries writes about a new segmented Enercon generator.
Reminds me of Kitestrings who also applied segments for his axial generator.
-
Iron sections?
-
So far I have not seen precise details of the technique used.
-
Guying makes it possible to shape the blades longer and longer I think and to build turbines with more megawatts.
(Attachment Link)
Is this new or old set up ?
-
It was recently that reports about this guyed rotor appeared in several wind magazines.
[attach=1]
-
With guying cables you get a much lighter blade I think.
And reinforced where the guy wire engages.
[attach=1]
-
The other extreme: bending Adani blades.
[attach=1]
-
Adani and Vestas do not have a direct drive.
I would also like to make a setup with a small axial with a transmission between the main shaft and the generator.
[attach=1]
-
MBrouwer, while your are working on something awesome.
So am I
I think perhaps we might share some personal details.
I think I need your machining skills and I think you can make use of my coil winding skills.
-
Let's look at the possibilities
What direction do you want to take with wind energy?
[attach=1]
-
Yes thank you.
I changed my mind regarding the PM. I am currently constructing a public post about my status and problem. Please join me there when you get around to it.
-
Please if you could have a stab at
https://www.fieldlines.com/index.php?topic=150806
-
You want: - a slow-turning mill
- no problem with the authorities
- you don't need a high yield.
An option is that I make you a model of an old Dutch mill with blades of approximately 1 meter. Then you can build a generator in there.
[attach=1]
-
wow, its a lovly model of our mills.
But I respectfully decline your offer ;) I am looking for something else.
-
A "Tjasker" I would also like to make. It would fit beautiful there on your waterfront and you can hang a small generator on it.
[attach=1]
-
Shaping the blades in polyester " Tjaskerlike "
And active blade adjustment for an adjustable rounds per minute.
[attach=1]
-
it's an idea indeed to use cloth. I am not sure though if they can make noise. But then again what I had planned might be noisy as well as I was planning to replace my current cup blades with much larger versions that can hinge in the middle as to allow for much less resistance when going against the wind and having springs pull them open again when the wind comes from behind.
Also making use of rigid insulation material rather than that heavy stuff I use now.
-
If you go with fabric it deteriorates and has to be replaced too often. May as well build something durable.
Tjasker is pretty simple enough if you want to pump water. But the deal with them is they can pivot 360 degrees. They are offset between the center of gravity of the rotor and pivot, so that the rotor drag makes it pivot and self align to the wind. Some of them are locked in place so that they do not run over their pump hoses. But mostly they seem to have some degree of range. With electrical generation this should not be a problem.
What is pretty interesting about this style is that drag is good. It will never be HAWT fast while rotating, which is fine. But your blades work as a long pivot arm works, which is in your favor for torque generation.
-
You want: - a slow-turning mill
- no problem with the authorities
- you don't need a high yield.
An option is that I make you a model of an old Dutch mill with blades of approximately 1 meter. Then you can build a generator in there.
(Attachment Link)
hahaha i realize now that you suggested to put my generator in that tiny mill model ;) Well the generator is going to be 1.32meter diameter. That will never fit. Nah don't worry in the meantime I found a way to connect the rotor the the column.
-
[attach=1]
A Tjasker would fit well in such a beautiful location.
I would make a real nice blade profile Ttjasker-like in colored polyester.
-
I think you mean well so I will ask my neighborhood. :
But honestly, More than 2 years I have been comming back to a VAWT. Of size
-
Do yourself, your family and the neighborhood a favor with a low blade-speed, no noise, a small generator and a nice workpiece that you always can control.
-
Striking on the forum is that we are struggling so much shaping the generator.
[attach=1]
-
Striking on the forum is that we are struggling so much shaping the generator.
(Attachment Link)
That's probably because the generator is the real work. Pictures make it look so easy. It is not. :)
-
I second that!
If we can keep things civil then I will admit that building an alternator is far more difficult than I had anticipated. Especially when the size increases.
And I am not even done with it yet.
All I can give is my mental support ;( Hang on my fellow Dutch builder. :)
I am so sorry that I am far behind your skills so I am probably of no use for the things your design is focussed at :(
I am trying a more "accessible to the newcomer" approach but even that is is turning out to require determination ;)
I am sure you will get there. I have looked at what you work on from time to time and I recognise skill when I see it!
-
[attach=1]
Wind energy fascinates me and I would like to discuss and apply (new) options for self-building.
-
[attach=1]
What we also can discuss is that with cores in the coils, much less strong (and therefore much less expensive ) magnets are needed for the same generator result.
-
(Attachment Link)
A Tjasker would fit well in such a beautiful location.
I would make a real nice blade profile Ttjasker-like in colored polyester.
Ok my brother. Let's have a talk about it.
So for you , which I would agree with, is the esthetics? I mean having a model of our heritage spinning around on my lawn would indeed be something totally cool.
But then what would I do if something breaks. Do I call you and you come fix it? ;) of course not. No I need to be able to understand all aspects of my own turbine so that I can see it break and then harden it on it's weak points.
Over 4 years of service I hope to have a turbine that is indestructible.
Of course I realize the non realisatie nature of my wishes. But over time I can see it spin, see it show signs of stress and then plan on how to make it stronger.
-
It is all about your area of knowledge and possibilities to make a windmill.
Maybe start with a small axial generator?
Driving that generator at an accelerated rate with a chain drive.
-
ok well then here we have got a conundrum ;)
As I know nothing about anything ;)
Anyway I do not which to start hijacking your thread with things that are not really related to your mission other than that you and I are seemingly in the same boat.
I will try and refrain from posting here stuff that really is only geared towards my particular situation so hopefully the next paragraph will be the last one at that;
I am still strong headed, others call it foolhardy, to first try a direct drive rather than a geared one. I think I can keep things under control at 1.32m diam. And if indeed I can then I just removed another several points of failure.
But ok ok. Let see how far I get. You are not the first to suggest me to go for a geared drive and that might mean that is because you all know so much more than I do ;). lets give me a few moments to experiment ok?
-
neodymium magnets are basically 1 million amp turns per meter, and when the magnet is in open air, the magnetic field strength inside the magnet is about 1 to 1.1 T depending on the grade. (n42 to n52)
steel has a resistance of about 1/1000 to 1/10000th that of air. but the magnet itself is an air gap, which is why the flux density only increases 50% when the magnet is shorted out.
alnico magnets have a permeability of about 10, which is why they can be easily demagnetized. they can have a flux density change by like 5:1 when shorted out with steel iirc. (.2T in open air, 1T inside a core)
so the whole point of an iron core, is to make the magnet field value far higher with less volume of magnet that would otherwise be required.
Also what Joestue writes here must inspire us to use an iron core in the coils.
-
People are sometimes really driven to build a savonius.
[attach=1]
-
The "mill" in that picture is not a true Savonius as it is set up.
Typical "S" types have the "buckets" overlapping.
[attach=1]
Not sure that the one pictured would even stay up in a decant wind.
However, I do agree, some will go to strange lengths :-)
Cheers
Bruce S
-
What to think of Mingyang's new 22 MW concept?
Which transmission and generator will be used there?
[attach=1]
-
What I read is that they use a medium speed gearbox and a permanent magnet generator.
Should we for diy also go in that direction with a small axial generator driven via an acceleration stage?
-
What I read is that they use a medium speed gearbox and a permanent magnet generator.
Should we for diy also go in that direction with a small axial generator driven via an acceleration stage?
Would only be viable in larger machines... a 2 meter rotor would lose to much power in the gearing... have to balance tower needs(larger the rotor the more robust the tower needs to be!) against rotor size, and cost of both... sure step up to a 2 1/2 or 3 meter rotor, but then step up your tower design...
-
For example this small generator with a 2- stage gear chain drive mounted in front of it.
[attach=1]
-
Very nice windings! What size is the wire?
Cheers
Bruce S
-
@ Bruce,
It's one of those small axial generators that you can buy on the internet for a price for which you can't make it yourself for.
-
Looks like Aliexpress. Scammers.
-
@mbower
IF you still have the link, would PM me with it please?
I'm curious about the wire as it looks like it's either very thin wire, or flat wire.
IF it is flat wire, then it is not worth the time due to the same issues using flat wire that even the guru's from years past on here have had.
IF it is very thin wire, then the voltage will be interesting.
I'm also betting the 2-stage is an external step not internal to this built unit.
@MattM I've ordered from Ali--express for years now and have always gotten what I ordered.
However, I always read and copy the description of the stuff I'm ordering and expect an answer from the seller long before I place an order.
Cheers
Bruce S
-
@Bruce,
Search for: 100 Watt DIY Micro Generator.
[attach=1]
Should the iron core and the backplate consist of laminations?
-
Why go this route when they sell more similar to Piggott for either 9 coils at $100 or 12 coils at $110? These tall coils look too deep relative to the DIY versions.
-
These coils have the great advantage that they have an iron core.
But I don't know what material the core is made of.
-
Sure looks like steel rather than simple iron. They do leave the steel core open in their set ups. Eddy currents need 2 dimensions to form. The open cores removes depth to the steel. You may get some eddies forming vertically but those should have minimal impact on cogging. Metal under a moving magnetic field will still heat. Is the open steel core able to cool off relative to the copper is the real question. They have different expansion rates and the steel will expand 10x faster than the copper.
-
[attach=1]
Isn't this just an axial version just like a radial version where there is a stator with teeth built up from stator sheet laminations.
The iron of the stator and the cores of the coils must be able to change polarity very quickly and must not become permanently magnetic.
-
It would be interesting to see if that was the case by mounting freely rotating magnets under each coil. If a north magnet was above the coil then the magnet under the coil should rotate its south pole towards the coil. But I believe that all the magnets interact simultaneously. The magnetic fields and coils do not match in numbers, so in reality only one coil at a time should truly be under polarization. The others are all in a state of transition.
-
Small axial generator to build a working model of a windmill.
[attach=1]
-
[attach=1]
9 coils / 12 magnets.
According to the Bavaria Winding Diagram Table, 9 coils / 10 magnets would be a better combination.
-
[attach=1]
This mini wind generator with planetary gearbox is a great starting point for a model of a Nordex windturbine.
-
[attach=1]
Starting with the top part of the mast as a tripod.
-
[attach=1]
The lattice mast is covered with polyester and has 2 sliding bearing rings in the top.
The pivot of the yaw-bearing fits into these rings.
-
[attach=1]
Base of the nacelle with the main bearing housing is mounted on the yaw bearing.
I now need to make the main axis.
-
Yes brother,
I am thrilled that you also just keep informing us over on this site.
Look, I hold you int he highest of esteem of course. And thus please keep hanging out here.
Yet do know that I read between the lines.
Anyway back on track. I would still like you on board on how to quantify this power generation aspect of our builds.
I sure am still failing at it. I just so hope that a new insight might just get the show on the road.
Kind regards
-
[attach=1]
Assembling the main shaft with slotted holes for blade adjustment.
-
[attach=1]
The main shaft directly drives the planetary gearbox.
-
To shape the spinner with the blade suspension I want to continue with parts I made earlier.
[attach=1]