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Joblow Regular Member Joined: 05/01/2010 Location: AustraliaPosts: 54
Posted: 02:57am 17 Jan 2010
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I've spent so much time reading this forums excellent posts and receiving answers to my questions that my wife is feeling neglected (more than usual )
I am now at the stage where it's time to start building my first mill, I've discarded the F&P option and want to build either an axial or radial flux machine from scratch and would dearly like your input to guide me to the best option.
My situation is:
Wind Speed: 30 kmh to 50kmh gusts, average 3.4 m/s,
I have a 15 metre traingular lattice tower and back shed with lathe, mill, welder etc, and lots of junk including three phase motors to 5 hp.
I am considering doing the chainsaw massacre type blade but don't know what is the best timber to use or how big to make them, (I suppose that all depends upon which gen option I decide to do )
Thanks again for all your input (received and anticipated) I will take photos of progress and post them occasionally to gather further comments.The man who never made a mistake never made anything
KarlJ Guru Joined: 19/05/2008 Location: AustraliaPosts: 1178
Posted: 04:34am 17 Jan 2010
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what do you want it to do?
Whats the budget?
If grid feeding then I'd be going BIG, economies of scale.
4m is a big turbine to build as a 1st project but thinking the chainsaw blades are based about this size.
this will be good for 2-4KW without much trouble.
The PVE2500 will be good for 96V but this might be too hard for batts, 100AH at 96V is at least $1000, a TC96 with dump load is the go here.
and on to Gordon and tules.....
a turbine this size is going to cost a few bob, just the magnets alone are dear ....
96V 200Turns 1mm wire 9 coils 24 magnets AXFX kind of thing in 400mm diameter.
Keep in mind big projects dont usually get finished.
perhaps start with a Hugh Piggot design and build that first, would be a shame to burn up all the bits and pieces first time it takes to the sky.Edited by KarlJ 2010-01-18Luck favours the well prepared
Joblow Regular Member Joined: 05/01/2010 Location: AustraliaPosts: 54
Posted: 05:46am 17 Jan 2010
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Hi karl,
Not sure what a PVE2500 is, but i want to grid tie.
I've started some seemingly overwhelming projects before and wondered 'what the hell have I started' but i just have to keep plodding on and hope to get there in the end. what bits are likely to burn up though?
thanksThe man who never made a mistake never made anything
KarlJ Guru Joined: 19/05/2008 Location: AustraliaPosts: 1178
Posted: 06:19am 17 Jan 2010
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Stator will burn up in AXFX with no furling sure as the sun shines unless of course there is a temp switch and some fancy electronics to shut it down, which I doubt in this case!
PVE2500 is a 2.5KW grid feed inverter 96-200V
TC96 is turbine controller so no batts
made by LAtronics (AUstralian made) a TC 96 has a dump load and the TC 48 does not without modification.
Theory here is the dump load will crush 2.5KW of output should things get too hairy for it (inverter and TC96) should the turbine make more than the inverter can handle or should the grid go down -(would hope it just shuts down the turbine if this happens)
Closer to the time you need it or other we have a couple of members who can get that gear at under retail.
Trev at basically natural for one will look after us forum members..
if you want real big then powerone just got their 4-6KW inverters certified for use in AUstralia, think thats some serious coin (6K kind of coin)Luck favours the well prepared
KarlJ Guru Joined: 19/05/2008 Location: AustraliaPosts: 1178
Posted: 06:37am 17 Jan 2010
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Forget that ....I was rambling
Phills / Gordon's OZ AXFX at 3m diameter and good for 2KW all day is the 1st timers ticket (even then beyond my scope!!!)
Phill reckons it took him a shedload of hours to build but cost of materials is reasonable as are the blade extrusions at this level too.
Budget in this case would be $2K for your mill and $2K for your inverter, a few batts, some wiring and electronics, misc $500.
so under 5K gets you a top performer in average winds with the balls to deliver the goods when the wind is up.
Luck favours the well prepared
oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686
Posted: 10:20am 17 Jan 2010
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Joblow.
Your windspeed indicates an average 50 watts with a 3m blade or 100w with a 4m blade. You have poor winds.
If your going to do this, you will need a fair size mill. Axial flux is the pick here. You need everything going for you.
There is precious little difference between say a 10' and 13 foot axial build. They could be identical if you wished, but the rotor will do better to be 14" rather than the 12 that is normal for 10 footers.
The magnets are the expensive part, at around 14.00 each magnet.need 24. 50x12mm rounds. N45 etc.
After that, it is cheap as peanuts. Wire can be from any source, even degaussing coils from TV sets and monitors.
The axial flux is very forgiving with coil winding, as 1 in hand to 6in hand has been done, depending on what wire is reasonably priced and at hand. Every coil can use different wire types if necessary, and the result will still be the same.... just try and keep the combined cross section and turns the same.
The steel rotors can be any 8mm plate steel you can find that is straight.
Can be laser cut, or chewed out with a angle grinder... both work exactly the same.
Clear radiata pine is good enough for blades... no knots is best..... I have always got damn knots, but it does not seem to matter unduly. Don't lose any sleep about getting them to weigh the same. It doesn't matter. With an axial, you can balance them on the tower as there is no iron drag to mask the balance. This is much better than balancing the blades separately or as a unit and expecting them to bolt on and stay the same.
On my last set for their maiden run, one blade was as much as 1/2 kilo out, as it was wet wood, and the others not so much, but ran without wobble with a simple balance weight.
The axial should cost not much more than the magnets and resin and wire. It can get expensive if you want a flash finish... but it won't work any better. The choice is yours. You can spend as much or as little as you want.
It does not require your lathe... but you will get a nicer job if you use it. Straight plate is important... or beat it straight if it is not. The rotors need to be close to planer with each other. This is not hard to do. A lathe will not necessarily help get it any better without thinning the plate unevenly perhaps... so beware what you do in the lathe.... unless you thickness both sides when done.
The rest of the steelwork is old pipe, and I used power pole bracing straps for the stator holding arms. Use more than 3. I use 9. This is overkill, but costs nothing extra for massive strength to instant stop the blades.
No special tools apart from a welder are necessary for the manufacture of these things.
The best thing about the axial (apart from the efficiency) is the ability to tune them easily. Stall can be eliminated by gap change, and cutin can be accurately wound for. It just does not get better for a wind junkie.
In your wind situation, you need all the help you can get, a radial will be less efficient here.
I'm rambling...
............oztulesEdited by oztules 2010-01-18Village idiot...or... just another hack out of his depth
KarlJ Guru Joined: 19/05/2008 Location: AustraliaPosts: 1178
Posted: 10:49am 17 Jan 2010
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'Tules awesome stuff, so what do we need to get started?
sounds like 2 x 14 steel discs and some kind of trailer hubLuck favours the well prepared
Joblow Regular Member Joined: 05/01/2010 Location: AustraliaPosts: 54
Posted: 12:41am 18 Jan 2010
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Good news about the radiata pine, I've got a massive one that is about to be felled, seeing my contact for scrap plate soon.
Where's the best place for magnets?The man who never made a mistake never made anything
Joblow Regular Member Joined: 05/01/2010 Location: AustraliaPosts: 54
Posted: 07:09am 18 Jan 2010
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I've just re-dicovered an old bullet welder(motor/generator) in the back of my back shed that puts out 275A @ 50V and 2900RPM, is converting this worth persuing?The man who never made a mistake never made anything
oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686
Posted: 11:28am 18 Jan 2010
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Yes Karl.
Trailer hubs are fine, as is most car front ends... but a trailer hub is simplest to deal with. If you ditch the dust seal, or modify it so it does not drag, almost frictionless hubs are a reality.
Any 8mm steel will do just has to be straight. If angle grinding it out, I guess it can be dodecagon rather than round. Makes no difference.
Cut out the center hole for the hub dust cap and axle nose with a holesaw, and drill the stud pattern out with a 1/2"drill......... plates are done.
Make a magnet template with a compass protractor and 2" holesaw.
Well thats the hard part done.
..... and on we go
..... use the bullet welder as a welder. It won't suit windmill duty at all
.........oztulesEdited by oztules 2010-01-19Village idiot...or... just another hack out of his depth
HeadsUp Regular Member Joined: 06/12/2009 Location: AustraliaPosts: 43
Posted: 12:11am 19 Jan 2010
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bullet welder would be worth a fair bit as scrap if you dont want to use it as a welder , they are not very efficient as a welder and too much rotating mass for a turbine , unless you were going to convert it to a dual wound alternator , change the winding connections and put 10-12 metre blades on it or something....lol ... that doesnt constitute advice , just throwing potentials in the air that would need to be assessed by a person with engineering talent
scrap dealers around me paying $ 7 kg for copper today but price varies alot between dealers and days
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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(more than usual 
)
