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brandnewb . . . . . . . . . . SLOW DOWN

I don’t know where you got the idea that I suggested a Vietnamese website.

That image of the rotors that I posted is from a big 4kW alternator that Dan Bartmann built years ago. It is just an image to show a setup with 2 rotors that you can build and use for testing.

The rotor setup that you build for testing should have only 8 magnets per disk.

The magnet wire should be between .9mm and 1.3mm. No smaller or bigger than that. That wire size can also be used for the big alternator for your VAWT.

The magnets that you showed on the links are the wrong proportions.

A magnet like this will work for testing and will also work for your big multipole alternator for your VAWT.

https://enesmagnets.pl/en/permanent-magnets/neodymium-sintered/block-magnets/50-x-20-x-20-n35-ndfeb-neodymium-magnet.html

If you use 8 magnets per rotor, the steel disks should be about 280mm diameter, and the thickness should be 9 or 10mm.

If you build this rotor setup, make sure that you build it in a way that you can adjust the air gap.

For now, forget about Teslas, braking force and terms like that.

Start thinking number of turns, resistance, air gap, RPM, volts and amps.

Ed

  Ok so now I am thoroughly confused.

I was still operating under the assumption that we are looking for some kind of breaking force ability. As it was stated here earlier it is the mechanical resistance the PMA needs to overcome to actually provide power.

Or should we perhaps concur on a different vantage point? Another,  with a more wide consensus?

I am open to any and all as long as I can get rid of this fog of war that is obscuring vision for the grunt soldiers like my self.
I am sure that the generals up top have 20/20 vision but I am defending my mates here at the front line.

Thank you Ed,

This means the world to me!

So I have been able to figure out where that image came from or at least determine that it is also used by a Vietnamese seller of PMA kits.
https://www.blogdiengio.com/p/nhan-lam-bo-kit-may-phat-ien-500w-1kw.html

here is a translation of what is written in the context of that image
"Get generator kits for 500w, 1kw, 2kw, 3kw, 5kw

Do you want to make your own generator but don't have time or are you simply lazy? Let us help you. The machines we make are close to the capacity and suitable for where you live. Please contact Lam Nguyen"

My complaint to sellers like this and to the endless videos being shared online that they always fail to mention how it was determined to have a certain rating.
That was the origin of my question to you in the PM magnets to watts.
Let alone it says nothing about the coil shape and the reasoning behind that coil shape.

And of course I trust you and I will listen to you and will set this up I just fear the RPM need to be really high in order for the voltage produced to be of any use.
But as you stated I do lack a lot of understanding yet so let us just go at it and see where this leads us.

So step 1 would be is to eyeball the dimensions of this setup yes?
I am having difficulties guessing as I do not see a clear reference point to work from.
Step 2 would be sourcing these type of magnets. And I can I have already checked.
https://www.supermagnete.nl/blokmagneten-neodymium/blokmagneet-40mm-40mm-20mm_Q-40-40-20-N
if we opt for a 60kg holding force

or we can go a little stronger with something like this
https://www.supermagnete.nl/blokmagneten-neodymium/blokmagneet-50.8mm-50.8mm-25.4mm_Q-51-51-25-N

Now obviously the relationship between cost and power is lost but that does not matter in the pursuit of science.

That Vietnamese design is a copy of the one created by the founders of this forum, coil shape and number of turns was came by experimentally... and with a little math as Ed showed you above. Formula is out there for magnetic flux, more math than I care to do, or use one of the simulators many pointed out to you... that bypasses the hard math I hate! Bad enough I have to do math designing electronics!

Please warn me ahead of time if this is getting out of bounds and I should be less loud.

Yet while waiting on a consensus if this Vietnam idea can serve as a good baseline I am staying focused on the actual topic of this thread!

So I have already ordered 1.5mm wire and 2mm wire. It will be here in a few days.

We will no longer be using anything smaller than 1mm wires from now on unless new evidence is brought up that warrants scrutiny.

Also I went to the other end of the spectrum with coil winding and went with a single wire (1mm) serpentine in a double density setup.



Here I find that at around the intended Hz for double density 7.6Hz this 5 coil serpentine can do a little less than 20mV.
And when that serpentine is subjected to 20mVDC then the field that can be measured between each wire at a distance of 10mm is around 4mT.

[ Guests cannot view attachments ]

I am beyond confused though to find that the last coil leg, at 10mm distance showed a 9mT reading.

Still a thing of beauty in operation.

I watched the whole vid just to see it operate  .

Robert is top-notch when it come to giving credit where credit is due.

I almost sent him a private email to let him know that the owner of that is also here.

Cheers to SKID!!!!

Bruce S

The steering was by the servo-rotors that turned away by a maximum of 90 degrees when the voltage of the car alternator in the bottom of the mast became too high.

in the meantime I have already a tentative conclusion that indeed a 1mm wire is the way forward as opposed to smaller.

What I did is have a coil of 1mm wire with 10 winds and a coil of 0.4mm wire at 40 winds.

Coil shape was narrow like in the double density tests.

When at around 8 Hz the 0.4 coil did around 160mV and the 1mm coil did around 48mV.

Then I hooked up each coil separately to the CVCC and fed in the voltage level they produced at 8Hz.

Then I measured the field strength at 10mm distance on both.

The 1mm coil had 16mT and the 0.4 coil had 8mT.

Unless I am tackling this wrong I think we have a clear winner {1}for when winding narrow.

But in the process just now of trying a coil shape that is matched to the magnets at 3.75 interval then this happened.



at 3.8 Hz the 10 winds 1mm coil did around 100mV and the 40 winds 0.4 coil did around 410 mV.
at 100Mv DC the 10 winds 1mm coil produces a field of 25mT in the center at 10mm distance. the field drops sharply when moving to the coil legs.

at 410mV DC the 40 winds 0.4 coil also produced a field of 25mT in the center at 10mm distance. the field drops sharply when moving to the coil legs.


Now I think it is a matter of finding the sweet spot of how thick we can get wires. 1mm might indeed be the absolute minimum.



{/1}

{2}this website actually does tell a lot about the coil and shape. so something to hold on to and work from in terms of dimensional reference point.{/2}
{3}albeit that the coils seem to vary from picture to picture. So I am not sure which one was intended for the rotor configuration and which KW rating was attributed to it.{/3}

I second it.

Hi brandnewb,

After your many requests for help, I'll agree to help you with the design of the alternator for your Phoenix VAWT.

I have read many of the posts on the diysolarforum, where you started your journey to build the 'sickest VAWT' over 2 years ago.

From the beginning, there were some users there and on this Forum that gave you good and sound advice. It is possible that you could not grasp what they were telling you. That is probably why you chose to continue to do it your way, even without a clear understanding of some of the simplest electrical terms and without an understanding of electromagnetism. It takes time and a lot of effort to learn that stuff.

At least you have perseverance and enthusiasm, that is good and commendable, but as I told you in the IM's, it will only help you if you have goals and stay focused.

I don't know how successful I will be in getting you back on the road, but I am going to give it a shot.

You have said many times that you want to do some tests that will help this Forum. So I am going to suggest some useful tests that you can do that will be helpful to us here and will help you acquire good data for your future BIG alternator.

I will start with this statement; you cannot get useful data by doing tests with the coils and magnets that you are using now, and I'll tell you why.

The magnets that you are using are too small and they have the wrong proportions of length to width, and they are too thin. Nobody will ever seriously think about using magnets like that to build an alternator. So, any tests that you do with those magnets are not useful when it comes to building an alternator.

When you asked about stacking magnets, Adriaan wrote this:

"However, if the total magnet thickness is about the same as the total air gap thickness, you can better keep it as it is"

I think that you missed that. What Adriaan said is that the ideal air gap for your 5mm thick magnets is 5mm. The 3 overlapping coils that you have are about 30mm thick? At 30mm, the flux reaching the coil will be less than 15%. You need thicker and wider magnets.

The coils that you are using now are useless for any type of alternator. The wire is too thin and with too many turns. That makes the resistance way too high.

This equation, P = (I^2) x R is used to find the power dissipated by a resistor in watts.

Remember this, when you build an alternator and you wire all the coils, the finished alternator becomes a large resistor.

Most of the alternators that are built by some of the members here have coils with resistance of .5 ohms or less. The resistance of your coils is about 9 ohms per coil.

P = (I^2) x R
P = power in Watts
I= Current in Amps
R= Resistance in Ohms

Example:

If resistance of one coil is .5 ohms, 3 coils in series is 1.5 ohms.

Assume that the current is 15 amps and voltage is 58 volts.

Total alternator power = 870 watts

P=(15x15) x 1.5 = 337 watts dissipated as heat in the stator.

Now let’s see how much power will be dissipated with 3 of your 9 ohms coils.

P=(15x15) x 27 = 6,075 watts (HEAT) dissipated in the stator.

That will not be called an alternator. It will be a copper smelter.

The bottom line, you need to keep coil resistance at .5 ohms or less.

The only way to do that is to use less turns and use at least 1mm wire for the coils.

If you can build a good testing platform with 2 rotors similar to this, it will help a lot:



It doesn’t have to be that big, 8 or 12 magnets per rotor should be OK.

You already have a Variable Frequency Drive. All you would need is a 2 HP 3-phase electric motor for turning the rotors at different speeds. Or you can use your Variac to turn a DC motor. The DC motor might be a better choice because the VFD's have a hard time running at very low RPM.

With that setup you can test different coils with different air gaps at different speeds and do other tests to get useful data that could also be of value to Forum members.

If you are interested in building the testing platform, let me know and I can help you with that.

Don't expect to get an electrical or electromagnetism education from Forums. We all learn mostly by doing and building things.

When you can sit in your warm home and look out the window and see the Phoenix spinning and making watts, then you will notice that you have learned quite a lot. And if you stay focused, that could be soon.

Ed

Reply

Here my obvious looking/.

For Me its ben posting videos

The system, login

BRCM;
What kind of height you have on the one in the pic? 15M+?

I had to look a few times to make sure that was in fact a tire that was being used for a water trough


Bruce S

yeah no, there is just no way yet I can demonstrate repelling to be generating more voltage than traditional in this dual rotor setup.
Not even when going double density.

And yes sure I am comparing apples to oranges making things rather hard to take seriously. Even for me the one designing and running the experiments.

But it ain't over till the fat lady sings yes?

Just do not hold you breath. I certainly no longer am not. But I just need to see so I can close the pages on this matter once and for all.

BTW, that is not to say that I think I do not need advice.

I think we have already established that I can use advice more than anyone else!!

So if you see something on the turbine that warrants attention then please let me know.

I will always love you for it even if I already saw that particular issue.
It is my 70% 30% 100% rule.

Even though I might already know 70% of the advice given. it are the 30% we are looking for. And the thanks extended to any advice should always be a 100%.

Please witness the bird at glide mode on the new column. Stealth if you will even. But then only for the auditory sensors.

ohh wow!! I just realized why going floating might be the dumbest idea ever.

All this effort I put into keeping things safe and working towards having this bird float on water. The very water my family , neighbors and my self swim in each summer. With potentially lethal currents going mayhem.

Bad IDEA

yeah no, this is proving rather impossible.
I am already at 8 seconds per revolution while the weather station registers 3.4m/s.
Now it is all about wind direction I think.

needless to say this will be difficult to really lay a finger on.

I think that when orienting magnets traditionally then it be important not too close. I think a lot of the field is not going through the coils but is diverted in between adjacent magnets.

Well that is what I will be testing next. To see if repelling without back plating (back plating in a repelling setup only hurts the field rather than benefit it)

But even so traditional with but a 15mm spacing between rotors already packs a punch. A hard one at that!

Look how crazy.


1.76 VAC at 3.6 Hz if I interpret the readings correctly. Now I would like to know if this is impressive or not.

{1}
So here the coils are 200 winds very narrowly wound @ 0.4mm diam wires.
They are not stacked yet spaced in such a manner to roughly end up with a 3 phase shift between them.
The reasoning (but open to debate as per usual) behind this configuration is that the heat dissipation ability can be more easily achieved than with while stacking coils.

And also regarding stacking coils, I still fear that the magnetic fields induced will suffer from interference. This phenomena one can see with waves.
But then again I first need to see that it in order to believe it

{1}

{2}
Also I am worried that once the coils start behaving like electromagnets (as is the intend after all to actually produce power) then the magnets on the rotors might become persuaded to let go of the back plating Not at all something one looks forward to when a PMA is in operation.
{2}

I think mostly these mills were designed to be hauled back to the farm with a horse drawn wagon and then assembled by hand with no additional lifting apparatus etc.  That is part of the reason for the angle iron tower.  It collapses nicely for shipping, and then is light enough to erect by hand with minimal tools. 

These type of windmills have a rotor which is much heavier than the 3-bladed rotor of an electricity generating wind turbine with the same rotor diameter. The rotor is heavy because of the many steel blades and the supporting structure. The head is heavy because of the cast iron reducing gear box and the crank mechanism. These type of windmills make use of a 4-legs angle iron tower with a wide base because the tower must be placed over a well with mostly a rather large diameter.

So these towers have a large base and therefore a high natural frequency. The maximum rotational speed of the rotor is low because of the low tip speed ratio and the used safety system. The rotational speed in rev. per second is therefore always lower than the natural frequency of the tower. For fast running rotors of electricity generating windmills, one often uses a slender tower with a low natural frequency and this frequency is passed by the rotor at already a low wind speed for which there is only a little vibrational energy in the rotor. So fast running rotors normally turn at a rotational speed much higher than the natural frequency of the tower. It is no good idea to use the wide base tower of a traditional water pumping windmill for a fast running rotor because then the rotational speed of the rotor in rev. per second can become the same as the natural frequency of the tower in Hz for high wind speeds and this will result in strong vibrations of the tower. The rotor will always have some mass imbalance or some aerodynamical imbalance and this imbalance starts the vibration of the tower if both frequencies are the same.

It IS his! I remember him testing that system to lower it...

I'm building a new CHP unit with, that will be big enough to heat both my shop and the house.

That'll be big enough for you and dozen of your neighbours!

doesn't require use of DEF

Good thing.

 https://www.sfu.ca/~mbahrami/ENSC%20388/Notes/Intro%20and%20Basic%20Concepts.pdf

Thw waterwheel in this video looks like yours.

https://www.youtube.com/watch?v=lCNcwsglZP8

I got a John Deere 6068T diesel that I'm building a new CHP unit with, that will be big enough to heat both my shop and the house.

These are from Deere’s industrial lineup of G-drive and marine engines. They are HPCR with electronic unit injectors. Rated for 50,000 hrs to overhaul on irrigation or generator duty. It is 180hp @ 1,800 rpm and holds 45 liters (11.9 gallons) of oil, making it possible to run 500 hrs between oil changes. Used drain oil from the engine can go into the fuel tank, diluted with fuel and be burned. It is suitable for driving a 125KW split-phase generator and considerably more fuel efficient than our Caterpillar DE50. The 6068T is a Tier II engine, doesn't require use of DEF, 106mm bore x 127mm stroke giving it 6.8L (415 cubic inches) of displacement. It is 17:1 compression ratio, turbocharged and designed for intercooling, so heat can be extracted from the intercooler as well as the cooling system and exhaust.

The cooling loop for the engine (heating loop for the house and shop) will go thru the intercooler, then thru the engine's cooling system, then thru the exhaust cooler. Exhaust temperature @ rated load is 1,000F. The cooling system will be high pressure (25 psi) so the final stage in the loop will be heated to 280F 50/50 glycol-water that goes to the heat exchangers. We need enough radiant heat from the engine to heat the generator room and fuel system when it's below -20F outside so the engine block and exhaust manifold under the turbocharger won't be insulated. The engine weighs 1,820 lbs wet, so it has decent thermal mass as well, for continued heating of the generator room/fuel system when it is shut down without having have to use auxiliary heating to heat the room in sub-zero temps.

I chose this engine because it is near the pinnacle of current technology in diesel engines for thermal efficiency. It has 42% brake thermal efficiency at full load (fuel energy converted to mechanical power), with 28% wasted in exhaust gas, 4% going to pumping losses in a four-stoke cycle engine, 26% of fuel energy dissipating to cooling media as heat rejections to the ambient, including 3% going to mechanical losses as heat. It can be run at partial loads to adjust electrical and heating output as needed, just as efficiently as it runs at full rated load. Modern electronically controlled diesels are a total different world from the mechanical injection diesels of yesteryear, as the electronically controlled units can adjust both fuel rate and timing on-the-fly to optimize cylinder and turbocharger boost pressure and minimize emissions at partial loads. Unlike Otto-cycle engines, diesels run at peak volumetric efficiency because they are un-throttled, so they are an inherent lean-burn design with air-fuel ratios as high as 200:1 at very light loads in modern electronically controlled engines. The best an old Lister thumper could manage was ~40:1 air-fuel ratio at idle and around 15:1 at full load - not much better than a Otto-cycle engine. These new diesels run so clean they don't even leave any black soot in the exhaust pipes anymore. This particular engine can't qualify for on-road use because of NOx emissions, as it doesn't use SCR and runs extremely high combustion temperatures because it doesn't have cooled-EGR. But for a CHP unit it is perfect.

Total cost of the project I estimate at around $105,000 - the engine itself was a $27,000 component. Unfortunately, none of our existing plumbing or heat exchangers will work because they are a low pressure system. So we have to start over from scratch on the heating/cooling loops. It won't be running for this winter, but hope to have it completed for initial testing by next fall, and in full operation for next winter.

Edit: another plus with this engine is that is classified as a heavy duty industrial engine. It is used in John Deere ag and constuction equipment as well as G-drive and marine applications. It has replaceable wet cylinder liners, four valves/cylinder, the inline-six configuration has perfect primary and secondary balance without use of balance shafts, and the water pump is gear-driven instead of belt. It is very similar in design to the big block Cat (3406E/C15), which I think John Deere copied it from. But like the big block Cats, which became the first 2 million miles to overhaul engine in heavy duty trucks, this engine is designed to last with minimal maintenance.