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DaveP68 Senior Member Joined: 25/11/2014 Location: New ZealandPosts: 292
Posted: 02:33am 14 May 2017
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After extensive testing of F&P 36 pole copper stators with black rotor caps, would like to publish data on how to build "The ultimate F&P Dual in the world"!
First cut in 36 pole stator needs to be wired 2x 6p Delta and feed into a capacitor doubler using 12 x 600 uf DC caps to make 300 uf AC value.
The main drive 36 pole stator needs to be wired 6x 2p Delta and feed into another capacitor doubler using 12 x 1200 uf DC caps to make 600 uf AC value.
The output of this "new ultimate F&P Dual in the world" with 2.8 - 3 m diameter blades will deliver up to 1200 W into a 48 VDC battery system or even more in a storm. That is 40% more peak power than a Dual F&P 42 pole unit can output.
The W/hrs of accumulated power output will also be greater (way more than 5%) than a Dual F&P 42 pole, but this will depend on location and blade diameter chosen.
I don't need a wind turbine to publish this information, as know these F&P stators like the back of my hand.
If someone takes interest in what is published here I can guarantee it will work if set up correctly.
Any questions feel free to ask, as any information you need is available for free
The great genius Tesla worked like this and gave away all his ideas. He never held a patient and we now have all this amazing technology thanks to him including our AC power grids.Edited by DaveP68 2017-05-15There are realities if you do not accept, will lead to frustration because you will be spending time on wrong assumptions and the results cannot follow! The Dunning Kruger Effect :)
joebog1 Senior Member Joined: 07/11/2015 Location: AustraliaPosts: 114
Sorry Dave, he held many patents, in fact I own a book with all his patents published.
But yes he did give a lot away, and those he didnt were stolen by the likes of Westinghouse and Bell.
Best regards JOe
DaveP68 Senior Member Joined: 25/11/2014 Location: New ZealandPosts: 292
Posted: 02:20pm 14 May 2017
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The point I was trying to make which you did pick up on was about giving away information for free. Not too concerned about him having filled patents. So I'm still correct at a fundamental level. I take risks in life can be slightly wrong sometime but mostly stay on track. Know a lot of people who try to go through like trying not to make mistakes, they don't end up getting much done!
A good quote to back me up; "A person who never made a mistake never tried anything new". Albert Einstein.There are realities if you do not accept, will lead to frustration because you will be spending time on wrong assumptions and the results cannot follow! The Dunning Kruger Effect :)
joebog1 Senior Member Joined: 07/11/2015 Location: AustraliaPosts: 114
Posted: 06:16pm 14 May 2017
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I in fact think he may have inadvertently started the free software foundation of which I have been a member since the 1980's. I dunno much, but if I can help anybody I surely do. Before I get mobbed with requests for information, Im a hardware engineer I used make mainframe machines, PE3205 mostly.
Joe
DaveP68 Senior Member Joined: 25/11/2014 Location: New ZealandPosts: 292
Posted: 11:59pm 16 May 2017
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Hi Joe
I've been told in words to the effect "oh you won't get any more than 400 W out of an F&P stator" on this website. Well there is the motivation to prove that limitation was wrong, if the correct F&P stator is chosen and set up correctly.
All the data that I've published over the last 6 months is all backed up by extensive real world testing. So if it states I can get 1000 W out of a single F&P stator at 575 RPM then that is what it is, not some opinion. That can be done into a battery, not some expensive MPPT inverter/charger.
Most of my testing has been into high power rated resistive loads. I even got a question of why I was using a resistive load for testing!! Anyone who asks that sort of question does't understand the basic electrical fundamental fact that an Alternator needs a load on it. Wow that's Ohm's law isn't it?? If you don't have a load on the output of a wind turbine the blades will go into runaway, not good
The big surprise for me was discovering that these F&P stators are a "constant current" output device. What this means is when the "most efficient" current output is reached then the voltage needs to increase in proportion with RPM. Also from what I can work out a few other "Permanent Magnet Alternator" are like this. If you don't want to except that fact, then you will never be able to get the best output from your F&P stator.
This is kind of how the high input voltage range MPPT inverters work. With MPPT though the wind power curve is additional variable which means the "most efficient" current is only reached at the higher voltage levels. I'm not the only one to discover this, just never seen anyone else on here mentioning it.
If given a challenge I normally excel and rise to it. Add criticism to that, you only motivate me more. So I'm deep thinker and like looking into the more complex issues that hide behind the scenes.
Did a search on PE3205 mainframe machines not much came up so not familiar with that one.
Cheers
DavidEdited by DaveP68 2017-05-18There are realities if you do not accept, will lead to frustration because you will be spending time on wrong assumptions and the results cannot follow! The Dunning Kruger Effect :)
joebog1 Senior Member Joined: 07/11/2015 Location: AustraliaPosts: 114
Posted: 12:31pm 17 May 2017
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I have been reading your posts and see you have spent some time on testing and development, so I have no reason to doubt your work.
Although wind is available to everybody, from your figures I would suggest that the F&P alternators you are designing would be more suitable to hydro as it "easier" to control a valve than operating the brakes of old Gaia. Less inertia I believe. Not everybody has access to a nice creek or river with sufficient fall to supply the energy though. Some years ago, the company I worked for, fitted a turbine made from a 3 phase motor using as far as I could see, one leg for control of magnetisation and the other two phases for two phase output. It used a"secret" controller so I never found out how it actually worked. It did work though and quite well except for the noise. The whine at high load could be heard for miles. I never did find out how it worked. It was made in northern NSW, but Ive forgotten where exactly. Off topic somewhat. https://en.wikipedia.org/wiki/Interdata https://en.wikipedia.org/wiki/PerkinElmer
Best wishes in the success of your work. Joe
Edited by joebog1 2017-05-18
Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406
Posted: 03:31pm 26 May 2017
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[quote]The big surprise for me was discovering that these F&P stators are a "constant current" output device. What this means is when the "most efficient" current output is reached then the voltage needs to increase in proportion with RPM. Also from what I can work out a few other "Permanent Magnet Alternator" are like this. If you don't want to except that fact, then you will never be able to get the best output from your F&P stator.
This is kind of how the high input voltage range MPPT inverters work. With MPPT though the wind power curve is additional variable which means the "most efficient" current is only reached at the higher voltage levels. I'm not the only one to discover this, just never seen anyone else on here mentioning it.
If given a challenge I normally excel and rise to it. Add criticism to that, you only motivate me more. So I'm deep thinker and like looking into the more complex issues that hide behind the scenes.[/quote]
You are quite right about the current source nature of alternators. The inductive impedance of the windings increases with frequency, so as it goes faster the current is held back in direct proportion to the speed increase, to remain almost constant.
Automotive alternators are exactly like this as well. If you have a "65 amp" alternator, that is what you get by design, and no need for current limiting as the engine rpm go up and down with normal driving.
The difference, is that an automotive alternator is being mechanically driven from an essentially infinite power source, at least as far as the alternator itself is concerned. And the output voltage is regulated both by the voltage regulator, and being connected directly across a fairly large partially charged battery.
The problem we face is rather different in that our driving source torque is what sets the limit on available output power, not the alternator itself.
I still feel very strongly that the only real solution to all of this is an electronic one involving a dc to dc switching converter to convert whatever electrical output the mechanical driving source and alternator can provide, to suit our load requirements, whatever they may be.
Voltages could either be stepped up or down smoothly and seamlessly as required, over the whole operating envelope to turn whatever rpm and torque is available, into whatever volts and amps are most suitable for optimum loading of the mechanical driving source.
Its not terribly difficult to do either.Cheers, Tony.
DaveP68 Senior Member Joined: 25/11/2014 Location: New ZealandPosts: 292
Posted: 12:44am 01 Jun 2017
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Hi Tony
Been off the site for a week, so sorry for delay in reply.
Thanks for your very insightful view of the challenge we face with being able to harness the maximum energy from the wind using F&P stators.
I have an idea to run by you. A possible way to control a "dc to dc switching converter" as you put it, is to use a special MPPT look up table in a large memory. The trick is to run an A to D converter measuring voltage rise/fall to directly drive the address bus of the ROM containing a large number of per calculated values. These values relate to how the best volts/amps of the PMA (F&P 36 pole stator in this case) need to matched with the correct TSR value of the blades.
The great thing is it is able to respond real time to any change in the wind, even heavy gusts. So how I see it in terms of what the lookup table does, is it controls value of PWM in the "dc to dc switching converter".
I've been sitting on this idea for some time, but now I've worked out the exact characteristics of the F&P 36 pole stators, everything becomes predictable.
I know the resident 'Diesel and Heavy Earth Moving Equipment Fitter' wont like me putting this concept on here...
What do you think?
Cheers
DavidEdited by DaveP68 2017-06-02There are realities if you do not accept, will lead to frustration because you will be spending time on wrong assumptions and the results cannot follow! The Dunning Kruger Effect :)
Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406
Posted: 04:10am 01 Jun 2017
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The problem as I see it, is correctly loading the wind turbine so it outputs the maximum possible mechanical power it is able to produce under the prevailing wind velocity. Either mechanically under-loading or over loading it will decrease the developed rotary mechanical power. There will be a power curve with a definite peak at some specific rpm and torque loading for every different specific wind velocity.
Unfortunately an alternator connected directly to a battery will have a rising power output with rising mechanical load that may not be especially well matched to the wind turbine over a wide enough wind speed range.
Below cut in speed we essentially get nothing, and at very high wind speed there will be more torque produced than the alternator can usefully turn into electrical power.
There are three ways we can attack this problem. Either with a variable pitch turbine, or with a constantly variable ratio gearbox ahead of the alternator, which is totally impractical, or we can do something electrically between alternator and battery.
We need a loss free method to adjust the mechanical loading on the turbine, and output a suitable voltage and current to suit our battery charging load.
Think about how you might do this with an (impractical) variable ratio mechanical gearbox. At very low turbine rpm, the gearbox might step up the alternator rpm so that the alternator output voltage is high enough to start battery charging, although at a very low current when the blades are barely moving. Giving ultra low cut in speed. The power will be very low, but if it goes on like that for hours or days, its still power worth having.
At medium wind speeds the gearbox might smoothly reduce back down to 1:1
As our wind velocity further increases, developed turbine horsepower rises approximately cubed law with wind speed increase, but our alternator cannot now load it sufficiently heavily to use all that developed torque at a 1:1 drive ratio.
So we might again need to step up our alternator drive ratio to fully load the turbine and extract maximum electrical power from it at higher wind speeds.
We could also do something with variable pitch blades, and there have been some very notable and ingenious efforts along those lines.
Once you get past the mechanical methods and try to do it electrically, we immediately strike a difficulty. While its entirely possible to boost the alternator output voltage to fix the cut in speed problem, nothing can really be done at the top end at really high wind speeds. The alternator simply cannot provide sufficient mechanical loading unless its enormous.
An alternator might be able to supply several kilowatts at several thousand rpm, but our turbine simply does not go that fast without a gearbox. And that is something we wish to avoid.
So really the cut in speed limitation is all we can hope to improve on electrically.
The capacitor multiplier is a terrific idea, but it needs to be adjusted by trial and error to suit a particular installation. I cannot see any simple way to get around that trial and error stage. But once its in and working, it should give a really worthwhile improvement to low end performance.
I believe a lot more can be done by controlling the loading and output voltage of the alternator with a switching power supply. But its not as easy to do with a wind turbine as it is with solar.
When you increase the electrical loading on a solar panel, it does not cause the sun to go dim ! But when you increase the electrical loading on a wind turbine it slows down, which may take time due to blade inertia. So although the initial power output rises, it may then begin to fall. So any feedback system either has to be very slow acting or it may start to surge or become unstable. In gusty conditions it may completely lose the plot.
So there are really two issues. The "power system" to control and adjust the volts and amps coming out of the alternator to some different volts and amps to suit our charging battery.
And the "control system" that decides what the wind is doing and what the power system needs to do to make best use of whatever wind is immediately available.
Two completely different topics.
Edited by Warpspeed 2017-06-02Cheers, Tony.
kitestrings Senior Member Joined: 23/04/2014 Location: United StatesPosts: 102
Posted: 04:33am 01 Jun 2017
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Has anyone experimented at all with the Midnite Solar Classic charge controller, or a similar unit? I'm not selling or promoting anything, but we have used these CC's for a few years now with some success. In their "wind mode" the user can input a power curve matched to a given alternator. Based on input voltage the controller tries as best it can to then follow that curve. Not quite as variable as Dave's suggestion, but along the same concept.
Warpd correctly points to one of the challenges which is the match throughout not just the wide band of available power, but the changing nature of the load (as the bank charges). What's also nice with the Classic is that they have a number of other features like load diversion. In our case we charge the batteries, then divert to water heating using a mode called "waste not" where you can set a differential relative to your charge set-points. When both are satisfied, then we divert to a resistive load bank and soon will motor-op the tail furling.
They offer "Clipper" units for wind, but I've no direct experience.
Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406
Posted: 05:02am 01 Jun 2017
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Its the sometimes rapidly changing nature of the wind, and the slow response of a large turbine that makes all this a lot more challenging.
I still believe an independent anemometer that rapidly tracks wind speed, and controls the turbine loading directly and very quickly is the best way to get the most performance under highly variable conditions.
The control tracking may be wrong or less than optimum (because it has not been accurately set up or tuned) but it will be very fast acting and completely stable.
There would then be some fixed relationship between measured instantaneous wind speed and instantaneous alternator loading that comes from some kind of lookup table.
It could even be as simple as a row of potentiometer adjustments, with each pot covering a small range of wind speeds. Just tweak each pot for maximum battery charging current when wind speed falls within that particular range, possibly indicated by an appropriate LED.
Cheers, Tony.
kitestrings Senior Member Joined: 23/04/2014 Location: United StatesPosts: 102
Posted: 05:03am 01 Jun 2017
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There's also a guy named Rob Beckers (Ontario, CAN) who has done quite a bit with a grid-tie inverter called Aurora that has a similar MPPT wind-track capability. He posts occasionally on the OP forum, but also moderates (I think) a forum called Green Power, or Green Power Talk I think it is -
What I like about the electronic approach is that all the complexity stays on the ground. Gearing and variable pitch is no small feat, though a couple guys from Germany & Finland on OP have been pretty successful with variable pitch. In our case we have three moving parts on the tower, and no diodes or components prone to failure (setting aside a direct lightning strike), everything else is in the house (rectifier, electronics, etc.)
~ks
DaveP68 Senior Member Joined: 25/11/2014 Location: New ZealandPosts: 292
Posted: 12:40am 02 Jun 2017
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Thanks to you both of for your valued input. Have heard of the Aurora inverters, but have never seen one in operation. I also do think that a an independent anemometer that rapidly tracks wind speed will help to keep things in check.
Here's a clue to where I'm coming from with this matching of the PMA's electrical characteristics to the 'Tip Speed Ratio' of the blades. TSR directly converts to RPM over a fairly linear range of operation.
Refer to this graph that I've posted in the past.
Here is how TSR can be calculated.
Lots of work to do, but it will be my next project now. Pretty well finished testing F&P stators for their full electrical characteristics. That part had to be competed first...There are realities if you do not accept, will lead to frustration because you will be spending time on wrong assumptions and the results cannot follow! The Dunning Kruger Effect :)
Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
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I used make mainframe machines, PE3205 mostly.
