Building the sickest ® VAWT ever. Brilliant minds unite please!!

[brandnewb]

since also on this software the search is simply just not as how a self respecting user of said search function would like it to operate I could not find my croc dundie telling kids what a real knife looks like.

Anyway that post was in the context of what real coils look like rather than the same old closed loop rehashed stuff we see over and over again in the books that we buy but do not get us anywhere.

Now croc dundee did call me a while back telling me about his thought on the matter whilst on his walkabout through the backlands.

And then it struck us both while on that talk.

That a stacked serpentine coil is in all intents and purposes similar to stacked closed loop coils yet then more efficient with wire usage.

Then I thanked Nick Dundee for the always inspirational talks we have!!

 

[brandnewb]

So I took a slight shortcut to see the field forming abilities of closed loop coil versus stacked serpentine coils.

And to my happy surprise sharing legs between coils (whether stacked serpentine or closed loop stacked) does NOT half the field in each coil.

So not only does serpentine (wheter single loop or stacked) reduce the total length of wire but also doubles the available field exposed to all magnets as opposed to traditionally spaced closed loop coils.

I hope I did it correctly but it would be such a shame if my findings turn out to be not well reached.



So I took a large 3 winds loop of wire and twisted it 10 times to end up with 11 stacked serpentine coils. Leg slot 1and 12 have only 3 wires. the ones in between 6.

Then I ran 1 amp through it and measured the field on several places.

To my surprise again the field in coil 1 and 11 are similar to that of the coils in between even though having only 75% of the total leg wires.

Then I ran the same experiment with a 6 winds closed loop coil of similar shape and ran the test in parallel.
The field was much higher in the closed loop coil.

Then I ran the experiment again with only the closed loop coil and then the field became similar to that of the stacked serpentine coils.

For sanity I then twisted the closed loop coil once ending up with 2 coils like in a stacked serpentine and the field did indeed not half. both coils have the same field but only opposite polarity.

I will still do the gravity torque tests but things are really looking good at the moment. I really hope I did not miss something critical and am heading towards a mayor blunder again.

 

[Hedges]

I'm presently taking and analyzing magnetic fields at work.

3-axis Barrington sensor sampled by NI DAQ.

Multiple sources of 60 Hz fields, in a room with 3-phase and various complex loads.
That gives 120 degree phase increments for voltage, but current can lead or lag. And rectifier/capacitor circuits are non-linear, clipping in a way that generates harmonics.

Each of 3 axis gives a time domain sequence of measurements.
FFT reports amplitude of frequency components, also phase.
At first I thought of just computing amplitude as RSS of the three axis. But each has different phase.
That is, it isn't linearly polarized, it is elliptically polarized. Field rises to a peak in X, but as that component falls it rises to a peak in Y and in Z.

I'm trying to tabulate contribution of each source (coil) and adjust them to cancel each other.

There are magnetic field cancellation systems which simply attempt to zero sensor feedback with something like PID (whether implemented analog or digital.) But before making that do its work of actively driving opposite field, I'm trying to attack problem at the source.

Just the opposite of your goal. You want strong field, I want no field.

 

[brandnewb]

WOW!!!

There might be hope still yet for the single rotor (magnets) dual stator (coils.)

please bear witness to the following.



with a 2 coil serpentine twisted (stacked as we used to call it), while it is not even optimized yet! I get this.



let us call this 550 mvAC at the intend Hz of 3.7.
Now double that because of there is an extra one of this on the other side;



I officially am able to keep true to my projection I made earlier about the the 2 months blah blah blah.

Screw that. I want to do more research first!!!!!!

I realize that then we loose the steel enhancement. Yet that is nothing we can deal with by optimizing the coils. After all we have already 2 coils cramped into 8mm thickness and rather odd looking. Not at all optimum from the magnets.

I think this 40% increase given by the steel backing, that will be lost when going dual stator, can be overcome by using 50% more wires per coil.

 

[brandnewb]

Screw that. I want to do more research first!!!!!!

and the windy season is closing to an end You know what! screw this again. I am going to hook things up just before there is no more wind to be had this season.

Just be sure that fat lady is not done singing yet!!

 

[brandnewb]

OK gang! I now have some new data to use as guideline.

Adding the extra disk of 96 magnets at a 17mm spacing does nothing to enhance the field {1}edit, not field, i meant voltage producing capabilities{/1} when the coil is so thin like the test coils we are using now.
Now I know it will enhance but then we need fatter coils. But this is early testing still.

But here comes the kicker!!

Having a single 100 winds coil compete against a double twisted serpentine coil of 50 winds yields the same results in terms of voltage producing.

And that was to be expected as thy both have the same amount of wire exposed to the field perpendicular to the field.



look how almost synchronous the waves are between ch1 the serpentine twisted into 2 coils and ch2 the single 100 winds coil.

This tells me that that serpentine, in one shape or another, is worth exploring as I can fit about 1 more coil using serpentine that way that using single coils.

Someone please challenge me on this as I need to get my head straight.

 

[brandnewb]

 

[brandnewb]

and I forgot to mention that the twisted serpentine exposes double or 200% more electromagnetic field to the magnets.

Here is my unconfirmed logic.

a single closed loop can produce x mT. when we twist that same coil into a serpentine then we get 2 x x mT.
Still the same amount of wire and resistance in that wire.
Now add to that the fact that twisted serpentine usees less wire than stacked coils would. Thus less resistance.

Somewhere in my logic there must be a mistake. otherwise why is not this a standard yet?

I can think of one thing though.

In a DIY setting one wants ease of production. Not something like I do with endless trail and error getting to a configuration that might perform a little better than the standard.

 

[brandnewb]

and this close up photo of the 2 coil serpentine was held into place with poly resin. I will order more as I am running out now

But I will also try (please Gary forgive me for still trying ) adding iron powder to the mix but this time not massage the coil wires into place.

Just to see if persuading the magnetic field through the wires by enhancing the magnetic permeability of the path (which is directly through the coils) will do anything for the voltage producing abilities of a coil

I know that one thing it will do is enhance the heat dissipation ability.

Another thing it is most likely to do is begging for shorted coils if not cast correctly.

But it might, just might also do something unexpected........

if cast correctly

 

[Hedges]

and the windy season is closing to an end You know what! screw this again. I am going to hook things up just before there is no more wind to be had this season.

Motor to spin it should be fine for tests, especially unloaded.
Somebody here wrote than when investors come to see a wind farm, the turbines are motored so it looks like they are all operating.

Why is waveform not uniform? Is rotational speed varying?
Now that you've got a full disk of magnets I expected a continuous sine wave of one frequency.

 

[brandnewb]

Motor to spin it should be fine for tests, especially unloaded.
Somebody here wrote than when investors come to see a wind farm, the turbines are motored so it looks like they are all operating.

Why is waveform not uniform? Is rotational speed varying?
Now that you've got a full disk of magnets I expected a continuous sine wave of one frequency.

Not uniform because hand spun and a lot of une en mechanical resistance so difficult to be constant.

I made a better attempt this time and reach around 900mvAC at around 3.7Hz

So the extra disk sure adds a lot of voltage generation ability! I just did not look well enough earlier.

I sat down and modeled the coil count;
closed loop = 15 per phase

Serpentine = 30 (maybe 31) per phase.

I abandoned overlapping phases(or more accurate coils of a different phase) as then there is no space for iron powdered cores to help the field forming and heat dissipation abilities.

 

[Hedges]

I abandoned overlapping phases(or more accurate coils of a different phase) as then there is no space for iron powdered cores to help the field forming and heat dissipation abilities.

Thermal resistance of conduction through the materials is probably lower (e.g. junction to case) and from materials to air higher (e.g case to air).
It could be individual wires with air moving over them would cool better, due to greater surface area.
However, at higher power the magnetic field would try to move them. Encapsulation provides mechanical support, should help prevent fatigue.

 

[brandnewb]

@Hedges you and I both lost our top contributor status just all of a sudden. Now in your case I think you have earned it.
In my case it might have been a forum software bug that lead to me getting that title.

sure feels bad to loose such an distinguished tittle though ;(

 

[Hedges]

Maybe he's just a bit bipolar/manic-depressive:

New User Group Created for Top Contributing Members

I can change the label in about 4 seconds. So it's whatever we can come up with or nothing at all. Seems like too contributor is not being favored, so I took it down. Let's see some more ideas and logic behind them and if everyone agrees on it, I will add it

diysolarforum.com

 

[brandnewb]

wow almost got myself sucked into a black hole again with that link you provided.

I am going to just stay in my bubble for now ok? else risk things blowing up in my face again.

 

[brandnewb]

hahahhaha

in an effort to find an affordable heat dissipation agent, as opposed to h-Bn borron nitrate which is ridiculously expensive) I found this

Magnesiumoxide (Technisch) - Labshop

1 kg

www.labshop.nl

this looks like a front of something more nefarious

 

[brandnewb]

So I just ran the most useless experiment of all time!! hmm maybe not so useless but I am rather unhappy with what I think I found..


I tried pressing a100 winds coil into a twisted serpentine yet with iron powder added.

I think the resin demands some space as I could not press it thinner than 19mm

Not at all what we want. We want something along the 14 to 16mm thickness.

So now the second magnet disk is spaced more apart than 22mm as otherwise things will violently attract (since now the coils is loaded with powder) and then one will generally have not the best of times.

And the mT is now around half of what it used to be between magnets using the tesla meter when measured somewhere in the middle.
How to proceed?

I am currently using coils with leg widths of 10mm. I think I can make them 12mm wide so that the coils will become less tall so that the magnet disks can come back to their original 17mm spacing. then things will eb jolly again I hope.

Or just give up and go back to 0.4mm wires ? that would feel like cheating.

 

[brandnewb]

ahh yes of course we want to know what the results were. well close enough to similar to the earlier results. No I mean literally rather similar results.

I could check if the coil was shorted but I do not have a good reason to assume that yet.;

I think the only feasible way to make 52 vAC at 3.7 Hz a possibility is to use coil legs wider than the magnet width.

At the expense of field forming abilities as then the powdered core will be less volume. At least that is what I think will happen.. I have no real data to support that assumption.

 

[brandnewb]

ahh also I forgot to mention that it takes about 2 minutes for this coil to reach 70c when 10;1 amps are pumped through it.

Now this is of course not a world record but let us take note of the surface area still exposed to air. if we fill that in then I think the coil will be much more amperage tolerant.

 

[brandnewb]

WOW, brain fart!!! i just saw the error in my thinking.

this bulge in the middle of the center leg is not becouse there was no more space to compress the wires in!!!


It was because the surface of the media used to apply the pressure was not rigid enough.

I mean look at how the ends are much thinner than the center.

That is because that is where the clamps were.


So this fat lady is indeed not done singing.