Author Topic: Christmas Windmill Time  (Read 26663 times)

0 Members and 1 Guest are viewing this topic.

taylorp035

  • Hero Member
  • *****
  • Posts: 1204
  • Country: us
  • Stressed spelled backwards is Desserts
Re: Christmas Windmill Time
« Reply #231 on: February 06, 2022, 04:30:54 PM »
Astro -  The amperage has to be pretty high at 4 volts.  Even at 40 amps, that's only 160 watts, which a 7' windmill can do without it being too windy.  Check out post #215 in this thread and the three graphs.  What I am showing in the graphs is that my generator was ramping up the load too fast versus how much shaft power the blades can provide.  I re-wired the alternator so it now can spin twice as fast before hitting the cut-in voltage and it pushes blades to a point where they will make more power than the generator can load it to.  The other highly complicated thing is that the blades were effectively stalling all of the time, so the lift and efficiency of the blades was really low (probably less than 10% efficient).  If I can get the blades to spin up faster when compared to a set wind speed (see reply #210 for a generic Cp graph), then I can easily triple my efficiency to say 30% and I'll have a lot more shaft power to play with.

To make this even more complicated, when I re-wired it, there is now less heat being lost in the windings since the current was cut in half on all of the coils (4x1 coils vs. 2x2 coils for each phase).  This greatly improves the efficiency, which means I need less shaft power.  And to add to this, I removed my diode in the system, so the voltage drop across that diode is now gone, which also was a huge waste of power.  The original setup was about 20% efficient at taking shaft power and sending it into the battery.   Now I'm hoping it's closer to 40-50%.

The alternator has 12 coils and 3 phases.  Each phase has 4 coils wired in parallel and they use 17 gauge wire.  The magnet rotor has 16 magnets that are 4"x1/2"x1/2" arranged in a NN-SS-NN-SS.... pattern such that there are 8 poles.  I did this due to the spacing of the 12 coils and how I fit my laminated steel shims to transfer the magnetic flux (very similar to an electric motor, specifically a brushless 3 phase motor).

It runs at about 30 RPM/ volt in the 4x1 configuration.  My old treadmill motor was about 35 RPM/volt.  Of course, my new alternator is going to output something like 30 amps at ~600 RPM versus only 6 amps with the treadmill motor at the same speed since there is a lot less resistance in the coils.  With the diode removed, the 30 amps will probably be more like 50 amps.

Astro

  • Sr. Member
  • ****
  • Posts: 280
  • Country: us
Re: Christmas Windmill Time
« Reply #232 on: February 06, 2022, 04:58:37 PM »
Astro -  The amperage has to be pretty high at 4 volts.  Even at 40 amps, that's only 160 watts, which a 7' windmill can do without it being too windy.  Check out post #215 in this thread and the three graphs.  What I am showing in the graphs is that my generator was ramping up the load too fast versus how much shaft power the blades can provide.  I re-wired the alternator so it now can spin twice as fast before hitting the cut-in voltage and it pushes blades to a point where they will make more power than the generator can load it to.  The other highly complicated thing is that the blades were effectively stalling all of the time, so the lift and efficiency of the blades was really low (probably less than 10% efficient).  If I can get the blades to spin up faster when compared to a set wind speed (see reply #210 for a generic Cp graph), then I can easily triple my efficiency to say 30% and I'll have a lot more shaft power to play with.

To make this even more complicated, when I re-wired it, there is now less heat being lost in the windings since the current was cut in half on all of the coils (4x1 coils vs. 2x2 coils for each phase).  This greatly improves the efficiency, which means I need less shaft power.  And to add to this, I removed my diode in the system, so the voltage drop across that diode is now gone, which also was a huge waste of power.  The original setup was about 20% efficient at taking shaft power and sending it into the battery.   Now I'm hoping it's closer to 40-50%.

The alternator has 12 coils and 3 phases.  Each phase has 4 coils wired in parallel and they use 17 gauge wire.  The magnet rotor has 16 magnets that are 4"x1/2"x1/2" arranged in a NN-SS-NN-SS.... pattern such that there are 8 poles.  I did this due to the spacing of the 12 coils and how I fit my laminated steel shims to transfer the magnetic flux (very similar to an electric motor, specifically a brushless 3 phase motor).

It runs at about 30 RPM/ volt in the 4x1 configuration.  My old treadmill motor was about 35 RPM/volt.  Of course, my new alternator is going to output something like 30 amps at ~600 RPM versus only 6 amps with the treadmill motor at the same speed since there is a lot less resistance in the coils.  With the diode removed, the 30 amps will probably be more like 50 amps.

"I re-wired the alternator so it now can spin twice as fast before hitting the cut-in voltage and it pushes blades to a point where they will make more power than the generator can load it to."
"To make this even more complicated, when I re-wired it, there is now less heat being lost in the windings since the current was cut in half"
 So in essence you raised the voltage and lowered the amperage making it perform better. OR just do not draw so many amps is what I was saying. Hit the sweet spot where the mill is turning and you are putting out a more stable and lower charging current. What you had going on was in essence a electrical breaking system. Lots of amps and it slowed down to much. Although a battery does charge faster with higher amps. So in the first stage of charging, you want to put as many amps into the batteries as they can handle without gassing, (that happens at a certain temp which I can not recall off hand and is why good charge controllers have a temp sensor)  AND WITHOUT stalling the mill. As the battery voltage catches up, you do not need as many amps and then finally when almost charged and drawing very little amps, you back the voltage off to the batteries peak voltage. That is the process you are trying to achieve. So again you can raise the voltage and thus lower the amperage of the mill. You can lower the amp draw of the load. Or you can let it buck with a relay that causes it to charge hard slowing the mill from say 400 rpm down to 300 (or whatever works for your situation), then cut the load, let the mill get back up to 400 rpm and then do it again and again and again until the batteries do not need such a high amp input because they are starting to get charged. If doing that, you are going to want a mill that can recover that hypothetical 100 rpms very fast or you want a mill that is hard to slow down. That will keep you charging most of the time, or as much as the mill can handle at a high amp draw from the load.
You can accomplish this with a current sensing or a voltage sensing relay, since the two are dependant of each other. You will have x amount of voltage at 300 rpms and x amount at 400 rpms in in our hypothetical example, we know that 300 rpm is as much as we want to stall the mill and so we set a low voltage circuit into play, cutting the load until another relay set at the voltage of whatever 400rpms makes, then reconnect the load of batteries. and ta da Bob's your uncle. It is also going to do the same thing in low wind situations, because it will try to take as much as it can without stalling the mill past whatever set points you use. So in low winds and you are only getting 25v, it is still going to take as many amps as it can to try and charge the batteries, but as soon as the voltage drops to say 20v, or whatever stall point you desire, it is going to kick the load off and let the mill speed back up.
 It is not complicated at all.
 As I said in my situation, I am going to have starting current of compressors and motors. So I want a mill that is hard to slow down. One that just wants to spin at the same speed all the time and does not get worried if the wind goes up or down for 10 seconds. OR if the load amperage goes up or down slightly for short amounts of time.
« Last Edit: February 06, 2022, 05:55:21 PM by Astro »

taylorp035

  • Hero Member
  • *****
  • Posts: 1204
  • Country: us
  • Stressed spelled backwards is Desserts
Re: Christmas Windmill Time
« Reply #233 on: December 25, 2022, 07:34:47 PM »
It's that time of year again where I decided it's time to resurrect the Christmas Windmill again.  I spent a bunch of time and effort to make the homemade "electric motor" style alternator work, but the cogging is just too high and I didn't even bother taking time to try out the mechanical centrifugal dog clutch I built since I had low expectations for it's durability.

I've decided to just make a really good axial flux alternator that will fit inside the nacelle.  (12) x 1" x 1/4" thick N52 magnets on 9 coils in a standard 3 phase arrangement.  I'm thinking 1/4" steel plate, 5 3/4" OD for the coils.  I'm thinking 1/2" or maybe 5/8" thick coils.  I'm also thinking of going with ~20 gauge wire to get the voltage I want.

Does anyone think using 12 magnets on coils that look like this will be too close together?   My goal is the most voltage/rpm in a space constrained nacelle (~5 3/4" square).  Here's what it looks like in CAD.
15110-0


The other option would be to use 6 magnets that are 1.25" in diameter or maybe 1.5".  With 12 magnets, the opposite polarity of the adjacent magnets approximately goes over both legs of a single coil at the same time.  In my head, that seems like a better situation that having only one magnet over two legs of a particular coil.

SparWeb

  • Global Moderator
  • Super Hero Member Plus
  • *****
  • Posts: 5452
  • Country: ca
    • Wind Turbine Project Field Notes
Re: Christmas Windmill Time
« Reply #234 on: December 26, 2022, 02:17:29 PM »
Off the top of my head, I'd keep the space between magnets equal to, or greater than, the space across the air gap between magnet faces pole-to-pole. 
The field lines will take the shortest distance to the nearest opposite pole, so don't offer them a shortcut that doesn't go through the coil.
Without much space between the coils there isn't a lot of resin binding and potting them rigidly, either.
So overall my opinion is that expanding this out from 5.75" diameter to about 6.5" would make you happy.

Despite what many say about covering the legs of coils, I find the math and the concept easier if you picture the field going from face to face between magnets, and getting the coil to fully wrap around that field.  Flux is Field X Area so why bother with straight lines.  The coils you have drawn are fine, but the 0.375" sharp turn doesn't get you any more flux than a 3/4" radius would, like the inner point.  The more rounded the radius the easier it is to wind, and the total length of wire is less (very slightly less, of course) for the same flux and voltage produced.

No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
System spec: 135w BP multicrystalline panels, Xantrex C40, DIY 10ft (3m) diameter wind turbine, Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024
www.sparweb.ca

taylorp035

  • Hero Member
  • *****
  • Posts: 1204
  • Country: us
  • Stressed spelled backwards is Desserts
Re: Christmas Windmill Time
« Reply #235 on: December 26, 2022, 08:42:22 PM »
Thanks for the feedback Sparweb.  I like your thinking on the corner radii.

Here's 1.25" and 1.5".  If I go 1.5", I might move the magnets inwards slightly.   At 5.75", I'm already pushing my limits on the clearance inside the nacelle.   My plan was to add a second alternator if I need it to perform differently.... either using my mini 4" diameter I already have built or make another one.  I could also cast another set of coils.  I don't want to carve another set of blades because the current ones are nicely matched to the tail for furling.
15113-0

15114-1


MagnetJuice

  • Hero Member
  • *****
  • Posts: 557
  • Country: ca
Re: Christmas Windmill Time
« Reply #236 on: December 26, 2022, 09:39:22 PM »
Hi Taylor,

Going with six magnets is a good idea. As SparWeb said, with 12 magnets there would be too much flux leakage from one magnet to the adjacent magnet.

Going with wider magnets creates an additional problem; there would be voltage cancellation from the magnets going over both legs of the coil at the same time. That could be solved by using 1.5 x 1 x .5 rectangular magnets as shown in this image.
15115-0

Another advantage is that the rectangular magnet has a total area of 1.5 inches. A round magnet that is 1.25 inches in diameter has a total area of 1.22 inches. In addition, the rectangular magnet is only 1 inch wide, so very little voltage cancellation. That is a win-win.

If you use two magnet rotors with six of those .5-inch thick rectangular magnets, you can wind the coils up to .5-inch thick if you need to. That would be a powerful little alternator, especially with your high RPM blades.

Ed
What can I do TODAY that would make TOMORROW a better world?

Bruce S

  • Administrator
  • Super Hero Member Plus
  • *****
  • Posts: 5370
  • Country: us
  • USA
Re: Christmas Windmill Time
« Reply #237 on: December 27, 2022, 01:46:40 PM »
I like MagnetJuice's idea better than the round ones too, however, I was thinking more of the trapezoidal shaped ones to conform better to the shape of yous coils.
Unfortunately, I do not see that  the advantages out-weighs the extra costs.

Bruce S
A kind word often goes unsaid BUT never goes unheard

taylorp035

  • Hero Member
  • *****
  • Posts: 1204
  • Country: us
  • Stressed spelled backwards is Desserts
Re: Christmas Windmill Time
« Reply #238 on: December 27, 2022, 09:25:04 PM »
Lets solve this with the FEMM software.  This was a quick and dirty simulation, so it's not to scale perfectly.   If I go with 12 magnets, there is definitely some flux leakage to the adjacent magnets and it reduced the peak field strength by ~10% versus the 6 magnet arrangement.  I'm primarily looking for max voltage given the package size, so I'm thinking having 90% of field strength but times 2 legs is better than 100% * 1 leg at a time.  Now, I've also noticed the width of the sweet spot is narrower, so maybe the advantage isn't quite is high as 180%.

15117-0

15118-1

taylorp035

  • Hero Member
  • *****
  • Posts: 1204
  • Country: us
  • Stressed spelled backwards is Desserts
Re: Christmas Windmill Time
« Reply #239 on: December 27, 2022, 11:41:55 PM »
I have real bench top test data on the 4" diameter alternator I'm basing this off of, so here is my best guess as to where this new alternator would land.  It looks like 22 gauge wire is going to be the right answer.

15119-0


SparWeb

  • Global Moderator
  • Super Hero Member Plus
  • *****
  • Posts: 5452
  • Country: ca
    • Wind Turbine Project Field Notes
Re: Christmas Windmill Time
« Reply #240 on: December 28, 2022, 01:28:13 AM »
Did you get Maxwell's equations in college?  I did, so I went back to my old books, and put it to use when figuring out how to build alternators.
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/maxeq2.html#c3

The thing you write about moving perpendicularly to wires isn't making sense.  You don't need these "multipliers".

Now you've got a FEMM model, then you're almost done.
Plot a line between the magnets where coil will be, set the model depth to 1" (the default anyway, but check it) or if you want, change the depth to equal the radial length of the magnet.
FEMM gives you the flux in Webers through that area.
Voltage is flux divided by time, or in other words the frequency of the alternator.  You know that from the RPM and the pole count.
That gives you the open-circuit voltage quite directly.
That's the power of using FEMM.

Note which features of the coil geometry are irrelevant to the result.  You wanted a corner bend radius?  Maxwell and Faraday don't care.
No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
System spec: 135w BP multicrystalline panels, Xantrex C40, DIY 10ft (3m) diameter wind turbine, Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024
www.sparweb.ca

MagnetJuice

  • Hero Member
  • *****
  • Posts: 557
  • Country: ca
Re: Christmas Windmill Time
« Reply #241 on: December 28, 2022, 02:58:43 AM »
If you are going to consider wire perpendicularity in your calculations, it would be good to know the following:

The size of the magnet that I suggested before is not the ideal magnet size. The ideal size would be trapezoidal as Bruce mentioned. Those are very expensive and hard to find.

If rectangular, then the best size would be 1-inch wide x 1.25 long. That is the size to be used in your calculations. However, I have not seen that size for sale in the US.

That is the reason that I suggested the 1.5 inches long, which is a size that is available for purchase in the US.

Ed
« Last Edit: December 28, 2022, 12:36:46 PM by MagnetJuice »
What can I do TODAY that would make TOMORROW a better world?

MagnetJuice

  • Hero Member
  • *****
  • Posts: 557
  • Country: ca
Re: Christmas Windmill Time
« Reply #242 on: December 28, 2022, 02:40:04 PM »
Here is an image of the 1 x 1.25-inch magnets superimposed over your coils.

15122-0

Ed
What can I do TODAY that would make TOMORROW a better world?

taylorp035

  • Hero Member
  • *****
  • Posts: 1204
  • Country: us
  • Stressed spelled backwards is Desserts
Re: Christmas Windmill Time
« Reply #243 on: December 28, 2022, 10:13:19 PM »
I'm still trying to grasp all the important concepts here.  I've thrown out my thinking of a moving magnetic field past a perpendicularly placed wire will create a voltage.

So the goal is to maximize the rate of change of magnetic field strength * area inside of the coil.  The coils size is fixed for the purposes of this discussion.  One way to change this is to increase the RPM, which is not on the table.  Another way is to increase average magnetic field strength in the coil so the rate of change ends up being more drastic.  If the magnets are too close together, this can reduce both the peak magnetic field strength and the adjacent magnets can start to flip the polarity near the edges of the bounded area, lowering the average peak magnetic strength within the coil.  Based on this, it seems like a large magnet that covers the whole coil would be the best answer for maximum voltage.

By adding more magnets, the sinusoidal frequency goes up by 2x, but the rate at which the flux changes does not necessarily increase, since in order for that to happen, you would need to have a stronger gradient of magnetic field strength going circumferentially around the rotor.  This gradient deteriorates as the adjacent magnets start to bleed off on one another.

SparWeb

  • Global Moderator
  • Super Hero Member Plus
  • *****
  • Posts: 5452
  • Country: ca
    • Wind Turbine Project Field Notes
Re: Christmas Windmill Time
« Reply #244 on: December 29, 2022, 12:04:33 AM »
You're getting it.

The "area" is counted per-loop, so every additional turn adds area.  This is how you design an alternator by playing off the number of turns (increases voltage) against the thickness of the wire (increases the current).  They trade-off proportionally, so you will strike a balance once you've picked a number of turns that gets whatever cut-in voltage/speed combination you are looking for and selected a wire size that fits in the space available.

A large magnet the same size as the coil is OK, but take note that inner turns of wire in the coil still only get the flux through the area they enclose, which is smaller.  To deal with that accurately (you don't need to be super-accurate, but if so...) then each layer of turns has a slightly growing area from inside to outside, adding to a sum for all turns in a coil.

The larger magnet, however will be closer to its neighbours.  As you've shown, that causes flux to leak across between magnets, not through the coil.  The same happens if you have more magnets on the rotor.  As you've realized, that also leads to them being too close together.

Your diagrams from Dec 26, and MJ's latest diagram are striking the balance for relative magnet and coil sizes, I think.

I still think the coils need a bit of space between, just for mechanical strength in the resin to hold them together.  You could make all mag's and coils a bit more compact, and that would also allow you some margin with the housing, which IIRC you said limits the diameter to 5.75".
No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
System spec: 135w BP multicrystalline panels, Xantrex C40, DIY 10ft (3m) diameter wind turbine, Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024
www.sparweb.ca

Bruce S

  • Administrator
  • Super Hero Member Plus
  • *****
  • Posts: 5370
  • Country: us
  • USA
Re: Christmas Windmill Time
« Reply #245 on: December 29, 2022, 08:49:14 AM »
SparWeb;
I agree with the idea of keeping space between to coils. I cannot put my hand on it and I haven't yet found the post. BUT somewhere on the wondrous forum there's a FEMM that showed the relationship of having space between the coils. From the bubbling memory the space was in the 1-3mm that allowed the field to collapse lessening the interference of one field to another.
NOTE: The words I'm using may be confusing or down right wrong,forgive me .
The extreme cold snap St. Louis experienced recently caused some extra items on the Public Safety vehicles to out right break and we're scrambling to get them fixed while mother nature gifts us with a bit of Cancun morning weather.
During my lunch breaks I'll continue searching for those posts.

Bruce S
A kind word often goes unsaid BUT never goes unheard

DamonHD

  • Administrator
  • Super Hero Member Plus
  • *****
  • Posts: 4125
  • Country: gb
    • Earth Notes
Re: Christmas Windmill Time
« Reply #246 on: December 29, 2022, 09:30:53 AM »
Bruce!  Letting your real life-saving job get in the way of forum work!  How could you?  B^>

Rgds

Damon
Podcast: https://www.earth.org.uk/SECTION_podcast.html

@DamonHD@mastodon.social

Bruce S

  • Administrator
  • Super Hero Member Plus
  • *****
  • Posts: 5370
  • Country: us
  • USA
Re: Christmas Windmill Time
« Reply #247 on: December 29, 2022, 01:08:26 PM »
Bruce!  Letting your real life-saving job get in the way of forum work!  How could you?  B^>

Rgds

Damon
:o  I know slacking off during the "Holidays" ???
A kind word often goes unsaid BUT never goes unheard

mbouwer

  • Hero Member
  • *****
  • Posts: 1023
  • Country: nl
Re: Christmas Windmill Time
« Reply #248 on: December 30, 2022, 05:06:36 AM »
A nice discussion. I would like to ask:
If you put an iron core package in the coils of the axial generator,
isn't it a great advantage that you can take the magnets much smaller for the same result?


MattM

  • Hero Member
  • *****
  • Posts: 1167
  • Country: us
Re: Christmas Windmill Time
« Reply #249 on: December 30, 2022, 10:10:53 AM »
I'm still trying to grasp all the important concepts here.  I've thrown out my thinking of a moving magnetic field past a perpendicularly placed wire will create a voltage.
In a nutshell, you never escape this relationship.  Just do not presume them to move in straight lines.  The wire has a magnetic field generated around it in a helix.  Every electrical current has a magnetic field, and every magnetic field has an electrical current.  This is unavoidable.

Quote
So the goal is to maximize the rate of change of magnetic field strength * area inside of the coil.  The coils size is fixed for the purposes of this discussion.  One way to change this is to increase the RPM, which is not on the table.  Another way is to increase average magnetic field strength in the coil so the rate of change ends up being more drastic.  If the magnets are too close together, this can reduce both the peak magnetic field strength and the adjacent magnets can start to flip the polarity near the edges of the bounded area, lowering the average peak magnetic strength within the coil.  Based on this, it seems like a large magnet that covers the whole coil would be the best answer for maximum voltage.

By adding more magnets, the sinusoidal frequency goes up by 2x, but the rate at which the flux changes does not necessarily increase, since in order for that to happen, you would need to have a stronger gradient of magnetic field strength going circumferentially around the rotor.  This gradient deteriorates as the adjacent magnets start to bleed off on one another.
The ironic thing is, your flux isn't changing with permanent magnets, its static by position.  The only change is the rotational speed of the magnets in relationship to the coils, or the rotational speed of the coils to the magnets.  This is why toroidal coils get so much focus, because they place emphasis on putting wire in the most places in curved space.

MagnetJuice

  • Hero Member
  • *****
  • Posts: 557
  • Country: ca
Re: Christmas Windmill Time
« Reply #250 on: December 30, 2022, 06:18:36 PM »
Hey Taylor,

Just like Bruce, I have a little free time during the Holidays, so I tried a few different designs and I think I found a configuration that would work in your very tight 5.75-inch nacelle.



It has ten coils and eight magnets. The magnets are 1.5 x .75. with a thickness of .5 or .375. That is a standard size that you can buy in N42 or N52 strength.

Ten coils and eight magnets will be wired for 5-phases and produces less torque ripple compared to 3-phases. That is less vibration for your little blades.

With two magnet rotors with the .5 thick magnets, it can output around 450 watts, depending on the RPM. That may be too much for your little blades, but you enjoy building blades, so longer ones in the future?

I don't have the patience for FEMM, maybe in the near future I will take the time to learn to work with it. Maybe you want to try this design with FEMM and see what you get.

If you decide to build this, just give me a ballpark number for the RPM that your windmill will be spinning at TSR. Then I can estimate the number of turns per coil and the wire gauge needed.

Just remember that cut-in voltage should be a little above TSR to keep your blades from stalling.

Ed
What can I do TODAY that would make TOMORROW a better world?

taylorp035

  • Hero Member
  • *****
  • Posts: 1204
  • Country: us
  • Stressed spelled backwards is Desserts
Re: Christmas Windmill Time
« Reply #251 on: April 30, 2023, 08:51:10 PM »
Progress has been made in the last week.  I used my CNC machine to wrap all 9 coils.   211 turns of 22 gauge wire.  0.625" thick.   Today, I glued the coils in place using a 6.2" diameter circular template and a 2.5" ID ring.

15450-0


15451-1

SparWeb

  • Global Moderator
  • Super Hero Member Plus
  • *****
  • Posts: 5452
  • Country: ca
    • Wind Turbine Project Field Notes
Re: Christmas Windmill Time
« Reply #252 on: April 30, 2023, 10:00:03 PM »
That's one heck of a slug of aluminum.  Must have worked great at spreading the pressure around.

22 gauge?  I thought you were going for low volts and high amps.
No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
System spec: 135w BP multicrystalline panels, Xantrex C40, DIY 10ft (3m) diameter wind turbine, Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024
www.sparweb.ca

taylorp035

  • Hero Member
  • *****
  • Posts: 1204
  • Country: us
  • Stressed spelled backwards is Desserts
Re: Christmas Windmill Time
« Reply #253 on: May 02, 2023, 10:25:21 PM »
That's one heck of a slug of aluminum.  Must have worked great at spreading the pressure around.

22 gauge?  I thought you were going for low volts and high amps.

It's a very large piece of silicon infused aluminum.  Really terrible to machine and the heat transfer is much lower than you would expect, but it has excellent fatigue strength.

And yes, I needed the turns to get the voltage high enough to hit a cut in speed of ~130-140 rpm versus 750-800 rpm on my 6 coil / 4" diameter smaller alternator.   I plan on wiring this new one as a 3 phase star arrangement, but I can always wire it in delta or put 3 coils in parallel for higher current if it works well enough.   The old 4" alternator was a single phase machine that I had fully wired in series.  The brushless in-runner designed alternator I made 2 years ago was actually 4 coils in parallel and then 3 phase since it's cut-in RPM was so low.

I hope to use my 7' diameter blades on this, while attached to my very conservative furling setup.  I should be able to dial it in as needed since I have my power meter that I can watch while running and also will record the max values.  When I ran the treadmill motor originally, it would not jump in current even during very gusty weather since it furled so well.  It was tuned so it could sit at 6 amps consistently on a 25+ mph day.

MattM

  • Hero Member
  • *****
  • Posts: 1167
  • Country: us
Re: Christmas Windmill Time
« Reply #254 on: May 03, 2023, 10:22:31 AM »
How many days a year will you be at 25+ mph day?

Mary B

  • Administrator
  • SuperHero Member
  • *****
  • Posts: 3169
Re: Christmas Windmill Time
« Reply #255 on: May 03, 2023, 12:53:24 PM »
If you can find a weather station near you on weather underground you can look back at historical data... this is mine from Monday... when standing up outside was a challenge! Sorry for the long chart... peak gust recorded on my software was 65mph, since this only uploads every 15mins you see more of an average for that day. I have yet to figure out how to go back a couple days on my software... not the most user friendly interface...

May 1, 2023
Time   Temperature   Dew Point   Humidity   Wind   Speed   Gust   Pressure   Precip. Rate.   Precip. Accum.   UV   Solar
12:00 AM   44.3 °F   32.0 °F   63 %   NNW   9.0 mph   17.0 mph   29.92 in   0.00 in   0.00 in      w/m²
12:15 AM   43.9 °F   33.0 °F   65 %   NW   8.0 mph   19.0 mph   29.92 in   0.00 in   0.00 in      w/m²
12:30 AM   43.5 °F   33.0 °F   66 %   WNW   9.0 mph   18.0 mph   29.92 in   0.00 in   0.00 in      w/m²
12:45 AM   43.4 °F   33.0 °F   67 %      8.0 mph   18.0 mph   29.92 in   0.00 in   0.00 in      w/m²
1:00 AM   43.1 °F   33.0 °F   67 %   NNW   12.0 mph   15.0 mph   29.92 in   0.00 in   0.00 in      w/m²
1:15 AM   42.7 °F   33.0 °F   68 %   NNW   12.0 mph   14.0 mph   29.92 in   0.00 in   0.00 in      w/m²
1:30 AM   42.3 °F   33.0 °F   69 %      15.0 mph   16.0 mph   29.92 in   0.00 in   0.00 in      w/m²
1:45 AM   42.1 °F   33.0 °F   69 %   North   8.0 mph   17.0 mph   29.92 in   0.00 in   0.00 in      w/m²
2:00 AM   41.9 °F   33.0 °F   70 %   NW   8.0 mph   14.0 mph   29.91 in   0.00 in   0.00 in      w/m²
2:15 AM   41.3 °F   33.0 °F   71 %   NNW   9.0 mph   13.0 mph   29.91 in   0.00 in   0.00 in      w/m²
2:30 AM   41.3 °F   33.0 °F   71 %   NW   11.0 mph   15.0 mph   29.91 in   0.00 in   0.00 in      w/m²
2:45 AM   40.9 °F   33.0 °F   72 %   NNW   6.0 mph   12.0 mph   29.91 in   0.00 in   0.00 in      w/m²
3:00 AM   39.8 °F   32.0 °F   73 %   NW   5.0 mph   11.0 mph   29.91 in   0.00 in   0.00 in      w/m²
3:15 AM   39.0 °F   31.0 °F   74 %   WNW   5.0 mph   10.0 mph   29.91 in   0.00 in   0.00 in      w/m²
3:30 AM   38.7 °F   31.0 °F   75 %   NW   8.0 mph   8.0 mph   29.91 in   0.00 in   0.00 in      w/m²
3:45 AM   38.5 °F   31.0 °F   75 %   NW   5.0 mph   9.0 mph   29.91 in   0.00 in   0.00 in      w/m²
4:00 AM   38.0 °F   31.0 °F   76 %   WNW   4.0 mph   10.0 mph   29.91 in   0.00 in   0.00 in      w/m²
4:15 AM   37.9 °F   31.0 °F   75 %   WNW   5.0 mph   10.0 mph   29.91 in   0.00 in   0.00 in      w/m²
4:30 AM   37.5 °F   31.0 °F   76 %   NW   5.0 mph   10.0 mph   29.91 in   0.00 in   0.00 in      w/m²
4:45 AM   37.4 °F   31.0 °F   76 %   NW   5.0 mph   11.0 mph   29.92 in   0.00 in   0.00 in      w/m²
5:00 AM   37.5 °F   30.0 °F   75 %      4.0 mph   10.0 mph   29.92 in   0.00 in   0.00 in      w/m²
5:15 AM   37.4 °F   30.0 °F   75 %   WNW   4.0 mph   9.0 mph   29.92 in   0.00 in   0.00 in      w/m²
5:30 AM   37.3 °F   30.0 °F   75 %   WNW   4.0 mph   10.0 mph   29.92 in   0.00 in   0.00 in      w/m²
5:45 AM   36.8 °F   30.0 °F   77 %   WNW   5.0 mph   12.0 mph   29.92 in   0.00 in   0.00 in      w/m²
6:00 AM   36.4 °F   30.0 °F   78 %   NW   8.0 mph   12.0 mph   29.92 in   0.00 in   0.00 in      w/m²
6:15 AM   36.1 °F   30.0 °F   79 %   NW   6.0 mph   11.0 mph   29.93 in   0.00 in   0.00 in      w/m²
6:30 AM   35.7 °F   30.0 °F   81 %   WNW   5.0 mph   12.0 mph   29.93 in   0.00 in   0.00 in      w/m²
6:45 AM   35.6 °F   31.0 °F   82 %   NNW   5.0 mph   10.0 mph   29.94 in   0.00 in   0.00 in      w/m²
7:00 AM   35.8 °F   31.0 °F   82 %   NW   5.5 mph   10.0 mph   29.95 in   0.00 in   0.00 in      w/m²
7:15 AM   36.5 °F   32.0 °F   82 %   NW   8.0 mph   10.0 mph   29.95 in   0.00 in   0.00 in      w/m²
7:30 AM   37.3 °F   32.0 °F   81 %   NW   8.0 mph   11.0 mph   29.95 in   0.00 in   0.00 in      w/m²
7:45 AM   38.4 °F   32.0 °F   79 %   WNW   7.0 mph   11.0 mph   29.96 in   0.00 in   0.00 in      w/m²
8:00 AM   39.8 °F   33.0 °F   76 %   NW   5.0 mph   13.0 mph   29.95 in   0.00 in   0.00 in      w/m²
8:15 AM   41.1 °F   33.0 °F   72 %   NW   4.0 mph   12.0 mph   29.95 in   0.00 in   0.00 in      w/m²
8:30 AM   42.2 °F   33.0 °F   69 %   NW   6.0 mph   15.0 mph   29.95 in   0.00 in   0.00 in      w/m²
8:45 AM   42.7 °F   33.0 °F   68 %   NNW   12.0 mph   15.0 mph   29.96 in   0.00 in   0.00 in      w/m²
9:00 AM   44.1 °F   33.0 °F   66 %   NNE   13.0 mph   16.0 mph   29.95 in   0.00 in   0.00 in      w/m²
9:15 AM   44.8 °F   33.0 °F   62 %      15.0 mph   19.0 mph   29.95 in   0.00 in   0.00 in      w/m²
9:30 AM   45.5 °F   33.0 °F   61 %   NW   9.0 mph   20.0 mph   29.95 in   0.00 in   0.00 in      w/m²
9:45 AM   46.5 °F   33.0 °F   59 %   NW   10.0 mph   26.0 mph   29.95 in   0.00 in   0.00 in      w/m²
10:00 AM   47.5 °F   33.0 °F   56 %   NNW   14.0 mph   28.0 mph   29.95 in   0.00 in   0.00 in      w/m²
10:15 AM   47.9 °F   33.0 °F   57 %   NNW   10.0 mph   29.0 mph   29.95 in   0.00 in   0.00 in      w/m²
10:30 AM   48.9 °F   34.0 °F   56 %   NNW   13.0 mph   27.0 mph   29.95 in   0.00 in   0.00 in      w/m²
10:45 AM   49.6 °F   33.0 °F   52 %   NW   10.0 mph   31.0 mph   29.94 in   0.00 in   0.00 in      w/m²
11:00 AM   50.5 °F   34.0 °F   52 %   NNW   29.0 mph   31.0 mph   29.93 in   0.00 in   0.00 in      w/m²
11:15 AM   49.4 °F   32.0 °F   52 %   NNE   17.0 mph   32.0 mph   29.93 in   0.00 in   0.00 in      w/m²
11:30 AM   50.7 °F   33.0 °F   50 %   NNW   30.0 mph   37.0 mph   29.93 in   0.00 in   0.00 in      w/m²
11:45 AM   50.7 °F   32.0 °F   49 %   North   30.0 mph   37.0 mph   29.92 in   0.00 in   0.00 in      w/m²
12:00 PM   51.1 °F   33.0 °F   49 %   NW   15.0 mph   34.0 mph   29.92 in   0.00 in   0.00 in      w/m²
12:15 PM   51.5 °F   33.0 °F   50 %      24.0 mph   31.0 mph   29.92 in   0.00 in   0.00 in      w/m²
12:30 PM   51.9 °F   32.0 °F   47 %      25.0 mph   29.0 mph   29.92 in   0.00 in   0.00 in      w/m²
12:45 PM   52.7 °F   33.0 °F   47 %      16.5 mph   34.0 mph   29.92 in   0.00 in   0.00 in      w/m²
1:00 PM   52.3 °F   33.0 °F   48 %   NW   14.0 mph   30.0 mph   29.90 in   0.00 in   0.00 in      w/m²
1:15 PM   52.8 °F   33.0 °F   47 %   NNW   20.0 mph   32.0 mph   29.90 in   0.00 in   0.00 in      w/m²
1:30 PM   53.2 °F   33.0 °F   46 %      23.0 mph   32.0 mph   29.90 in   0.00 in   0.00 in      w/m²
1:45 PM   53.9 °F   32.0 °F   44 %   NW   22.0 mph   39.0 mph   29.90 in   0.00 in   0.00 in      w/m²
2:00 PM   54.0 °F   33.0 °F   44 %   NW   10.0 mph   36.0 mph   29.90 in   0.00 in   0.00 in      w/m²
2:15 PM   54.5 °F   32.0 °F   42 %      24.0 mph   33.0 mph   29.89 in   0.00 in   0.00 in      w/m²
2:30 PM   54.9 °F   32.0 °F   42 %   NNW   12.0 mph   31.0 mph   29.89 in   0.00 in   0.00 in      w/m²
2:45 PM   54.8 °F   32.0 °F   41 %   NNW   30.0 mph   36.0 mph   29.89 in   0.00 in   0.00 in      w/m²
3:00 PM   54.1 °F   31.0 °F   42 %   NNW   20.0 mph   32.0 mph   29.89 in   0.00 in   0.00 in      w/m²
3:15 PM   55.3 °F   32.0 °F   41 %   NNW   14.0 mph   30.0 mph   29.89 in   0.00 in   0.00 in      w/m²
3:30 PM   54.5 °F   32.0 °F   42 %      19.0 mph   34.0 mph   29.89 in   0.00 in   0.00 in      w/m²
3:45 PM   54.0 °F   31.0 °F   41 %   NW   15.0 mph   31.0 mph   29.88 in   0.00 in   0.00 in      w/m²
4:00 PM   54.5 °F   32.0 °F   42 %   NNW   21.0 mph   28.0 mph   29.89 in   0.00 in   0.00 in      w/m²
4:15 PM   54.3 °F   32.0 °F   42 %      23.0 mph   26.0 mph   29.88 in   0.00 in   0.00 in      w/m²
4:30 PM   53.5 °F   31.0 °F   42 %   NW   14.0 mph   30.0 mph   29.89 in   0.00 in   0.00 in      w/m²
4:45 PM   54.0 °F   31.0 °F   42 %   NW   16.0 mph   28.0 mph   29.89 in   0.00 in   0.00 in      w/m²
5:00 PM   54.1 °F   32.0 °F   43 %   North   14.0 mph   27.0 mph   29.89 in   0.00 in   0.00 in      w/m²
5:15 PM   54.6 °F   32.0 °F   42 %   NW   20.0 mph   29.0 mph   29.89 in   0.00 in   0.00 in      w/m²
5:30 PM   54.3 °F   32.0 °F   42 %   NW   17.0 mph   29.0 mph   29.89 in   0.00 in   0.00 in      w/m²
5:45 PM   53.7 °F   31.0 °F   42 %   NNW   22.0 mph   30.0 mph   29.89 in   0.00 in   0.00 in      w/m²
6:00 PM   52.8 °F   30.0 °F   41 %   NNW   8.0 mph   28.0 mph   29.89 in   0.00 in   0.00 in      w/m²
6:15 PM   52.3 °F   30.0 °F   42 %   NNW   19.0 mph   24.0 mph   29.90 in   0.00 in   0.00 in      w/m²
6:30 PM   52.8 °F   31.0 °F   43 %      18.0 mph   22.0 mph   29.89 in   0.00 in   0.00 in      w/m²
6:45 PM   52.3 °F   29.0 °F   41 %      17.0 mph   26.0 mph   29.89 in   0.00 in   0.00 in      w/m²
7:00 PM   51.7 °F   30.0 °F   44 %   NW   12.0 mph   23.0 mph   29.89 in   0.00 in   0.00 in      w/m²
7:15 PM   51.5 °F   29.0 °F   42 %   NNW   11.0 mph   24.0 mph   29.89 in   0.00 in   0.00 in      w/m²
7:30 PM   50.8 °F   30.0 °F   45 %      12.0 mph   21.0 mph   29.90 in   0.00 in   0.00 in      w/m²
7:45 PM   50.1 °F   28.0 °F   43 %   NNW   12.0 mph   23.0 mph   29.90 in   0.00 in   0.00 in      w/m²
8:00 PM   49.6 °F   29.0 °F   45 %   NW   12.0 mph   19.0 mph   29.90 in   0.00 in   0.00 in      w/m²
8:15 PM   49.0 °F   29.0 °F   46 %   NNW   10.0 mph   18.0 mph   29.90 in   0.00 in   0.00 in      w/m²
8:30 PM   48.8 °F   29.0 °F   47 %   North   12.0 mph   16.0 mph   29.90 in   0.00 in   0.00 in      w/m²
8:45 PM   48.1 °F   29.0 °F   48 %   NW   10.0 mph   19.0 mph   29.91 in   0.00 in   0.00 in      w/m²
9:00 PM   47.3 °F   30.0 °F   50 %      10.0 mph   14.0 mph   29.91 in   0.00 in   0.00 in      w/m²
9:15 PM   47.1 °F   29.0 °F   50 %      6.0 mph   17.0 mph   29.92 in   0.00 in   0.00 in      w/m²
9:30 PM   46.9 °F   30.0 °F   51 %   NNW   11.0 mph   19.0 mph   29.92 in   0.00 in   0.00 in      w/m²
9:45 PM   46.9 °F   29.0 °F   50 %      9.0 mph   17.0 mph   29.93 in   0.00 in   0.00 in      w/m²
10:00 PM   46.3 °F   30.0 °F   52 %   NNW   11.0 mph   15.0 mph   29.93 in   0.00 in   0.00 in      w/m²
10:15 PM   46.2 °F   30.0 °F   52 %   North   8.0 mph   13.0 mph   29.94 in   0.00 in   0.00 in      w/m²
10:30 PM   45.8 °F   30.0 °F   54 %      8.0 mph   13.0 mph   29.95 in   0.00 in   0.00 in      w/m²
10:45 PM   45.3 °F   30.0 °F   55 %      16.0 mph   18.0 mph   29.95 in   0.00 in   0.00 in      w/m²
11:00 PM   44.2 °F   29.0 °F   56 %   North   9.0 mph   16.0 mph   29.96 in   0.00 in   0.00 in      w/m²
11:15 PM   43.4 °F   30.0 °F   59 %      9.0 mph   13.0 mph   29.96 in   0.00 in   0.00 in      w/m²
11:30 PM   43.7 °F   30.0 °F   58 %   NNW   5.0 mph   8.0 mph   29.96 in   0.00 in   0.00 in      w/m²
11:45 PM   43.8 °F   30.0 °F   59 %   NW   3.0 mph   6.0 mph   29.96 in   0.00 in   0.00 in      w/m

taylorp035

  • Hero Member
  • *****
  • Posts: 1204
  • Country: us
  • Stressed spelled backwards is Desserts
Re: Christmas Windmill Time
« Reply #256 on: May 03, 2023, 05:34:59 PM »
How many days a year will you be at 25+ mph day?

Probably 20-30 days a year.  There's always cold or warm fronts sweeping across the great lakes region.  I just want the windmill to not overspeed.  Currently the design works quite well and I can add more weight to the tail to very controllably adjust the max RPM.   I've seen days where it's over 30 mph and it it's holding max power quite steady while the blades are ~80+ degrees out of the wind.


And thanks for sharing Mary B!   April was quite the month here where it snowed 3 times and I got sun burned 3 times.  And for May, it decided to snow for the last 3 days.  It's been a weird winter with only half the snow we normally get/
15452-0

Mary B

  • Administrator
  • SuperHero Member
  • *****
  • Posts: 3169
Re: Christmas Windmill Time
« Reply #257 on: May 04, 2023, 01:28:08 PM »
How many days a year will you be at 25+ mph day?

Probably 20-30 days a year.  There's always cold or warm fronts sweeping across the great lakes region.  I just want the windmill to not overspeed.  Currently the design works quite well and I can add more weight to the tail to very controllably adjust the max RPM.   I've seen days where it's over 30 mph and it it's holding max power quite steady while the blades are ~80+ degrees out of the wind.


And thanks for sharing Mary B!   April was quite the month here where it snowed 3 times and I got sun burned 3 times.  And for May, it decided to snow for the last 3 days.  It's been a weird winter with only half the snow we normally get/
(Attachment Link)

Have t remember, April is one of the windier months as winter fights spring... summer doldrums can be days of light winds...

If you deep search weather underground you may find a weather station only a couple miles form you... mine uploads to it for example and everyone in town uses my data, so does the National Weather Service, it fills in a gap they had in coverage for an area with its own climate... Buffalo Ridge NW shadow zone. The forecast using my data is way different than an airport just 25 miles away!

taylorp035

  • Hero Member
  • *****
  • Posts: 1204
  • Country: us
  • Stressed spelled backwards is Desserts
Re: Christmas Windmill Time
« Reply #258 on: September 09, 2023, 09:11:23 PM »
I made the magnet rotors and did some quick bench testing.  The single coil voltage at about 60 RPM was 1.5 volts.  What was weird was when I did 3 coils in series to make a final single phase, it only did 2-2.5 volts.  I was expecting it to be closer to 4 volts.  I was pretty careful in marking the direction of each coil and everything should be spaced fairly evenly considering the care I put into assembling the magnets and coils.

15586-0

15587-1

15588-2

SparWeb

  • Global Moderator
  • Super Hero Member Plus
  • *****
  • Posts: 5452
  • Country: ca
    • Wind Turbine Project Field Notes
Re: Christmas Windmill Time
« Reply #259 on: September 10, 2023, 11:32:32 PM »
That's one Heckuva backing plate.  Just for testing purposes?

Try connecting just 2 coils and see if you get 2x voltage or not.  Then connect the 3rd and see if it adds the same increment.

Has the lathe been turning 60 RPM for each test or has the speed been changed?
No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
System spec: 135w BP multicrystalline panels, Xantrex C40, DIY 10ft (3m) diameter wind turbine, Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024
www.sparweb.ca

taylorp035

  • Hero Member
  • *****
  • Posts: 1204
  • Country: us
  • Stressed spelled backwards is Desserts
Re: Christmas Windmill Time
« Reply #260 on: September 11, 2023, 10:10:59 PM »
The steel was cheap versus the price of more magnets.  My FEMM simulations suggested it was the best bang for my buck versus going with 3/8" magnets.  They are also easier to bore such that they run true on the shaft.

I'll have to try the 2 coil test.   I'm assuming there shouldn't be anything funny going on if I just jump 2/3rd's into my 3 coil series with alligator clips?

The lathe was the same RPM for all tests.  I don't know the exact speed... it's a 1931 Sears, so it's belt driven and is one of the lower quality lathes in existence.  But it was the only machine I had that could chuck up a 1" shaft.

SparWeb

  • Global Moderator
  • Super Hero Member Plus
  • *****
  • Posts: 5452
  • Country: ca
    • Wind Turbine Project Field Notes
Re: Christmas Windmill Time
« Reply #261 on: September 11, 2023, 11:32:44 PM »
As long as you're only measuring voltage, then no real current flows.  Without current, there's no torque, so nothing funny should happen.
If you have a short somewhere, then actually you will still see something funny (vibration) which would be an important sign.

Don't worry about having accurate 60 RPM.  I was only asking about the consistency, and that will be consistent enough if you leave the belt on the same pulley, of course.
No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
System spec: 135w BP multicrystalline panels, Xantrex C40, DIY 10ft (3m) diameter wind turbine, Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024
www.sparweb.ca

taylorp035

  • Hero Member
  • *****
  • Posts: 1204
  • Country: us
  • Stressed spelled backwards is Desserts
Re: Christmas Windmill Time
« Reply #262 on: September 25, 2023, 08:44:31 PM »
I had some fun by running my old windmill alternator using my brushless RC car controller.  It wasn't too excited by my temporary alligator clip power leads, but it spun up to ~200 RPM and had about as much torque as I could do by grabbing the 1" shaft.  It was surprisingly smooth.


I also removed it from the nacelle tonight and got it off the shaft.  I didn't think it was going to come apart in one piece considering my previous experience, but after 45 minutes, we were able to slide it off.

I was thinking, I want to redistribute the magnets so it has less cogging for future projects by making a new rotor.  If any of you have an idea of a lower cogging configuration, let me know.  I have 16 magnets and the current configuration had two side by side for 8 exposed magnetic poles.  These lined up with the 12 coils, so there was 4 magnets at their closest points to the laminations at any given time.   I was thinking of going with 13 magnets that were evenly spaced, but that would be weird with an uneven amount of +'s and -'s.  I could do 14, but with vernier spacing every 7 magnets.  Or I could 14 with vernier spacing over all 14.

Next up is to squeeze the new alternator into the nacelle.  It's going to take a bit of cutting to make it fit since I got carried away with the size of my stator.

SparWeb

  • Global Moderator
  • Super Hero Member Plus
  • *****
  • Posts: 5452
  • Country: ca
    • Wind Turbine Project Field Notes
Re: Christmas Windmill Time
« Reply #263 on: September 26, 2023, 02:18:22 AM »
It's holding together after all this time!

Sticking with just 8 poles, you can try variations on the exact 45 degree position of each magnet.  Like 43,47,43,47,43,47,43,47.  Another approach is to skew them a little.  You could try a few variations of this inside the stator you have and you'd know which one is best.  Then go on to other pole/coil counts.

I don't entirely understand the cogging you experience, because there isn't much iron in your stator.
No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
System spec: 135w BP multicrystalline panels, Xantrex C40, DIY 10ft (3m) diameter wind turbine, Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024
www.sparweb.ca