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Hi, Just started playing around with the whole wind gen thing... I'm having fun. I have made the pole, frame/rack to hold the motor and tail assembly. I have tried several blades (PVC). I am happy with the mechanics and it spins the old alternator very well in any breese. I used the old alternator just to test the whole rig, so now I need to get the electrics right. I see in the good old USA there is a group called Bluewindpower.com who have put together a very highly rated permanent magnet alternator.
Is anyone making specialised PMAs in Aus or NZ? I have also noticed that most of the wind generator are feeding DC down the line... why not send AC down the line then rectify it near the battery?
I am finding it hard to get info on the best motor to use.
cheers davoone day oil, coal & gas will eventually run out...
wind and sun are here forever.
hello...?
Gill Senior Member Joined: 11/11/2006 Location: AustraliaPosts: 669
Posted: 12:28pm 17 Sep 2008
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G'day davo,
Welcome to the forum.
You're sort of working back to front by making blades then trying to find a gen to match. The better way is to find a gen then build blades etc. to suit it.
What do you mean it's hard to find info on the best motor? This site is full of info on it. The Fisher & Paykel Smartdrive suits all usual voltages, puts out good power and is cheap as chips. Price per Watt, you wouldn't do better with a converted alternator. The yanks have no access to F&P's at scrap value like we in the South West Pacific do so they have to resort to re-engineering or building whole new generators. Poor fellows. There is no one commercial alternator modification business in Au/NZ that I know of. No market I guess.
Some do feed AC down the pole for various reasons though it does require an extra wire, extra slip ring with the added co$t. If that's not an issue, then go for it. was working fine... til the smoke got out.
Cheers Gill _Cairns, FNQ
Hi Gill thanks for the quick reply. There is method in the madness, I live near the ocean on a hill with plenty of sea breese. The practice session was just that to practice. I made a number of different blade out of PVC with quiet a varied affect. I had not read about the F&Ps when I hit the forum.... I know where I am heading tomorrow.. :-)
My question on the AC related around the fact that AC will travel longer distance with out voltage drop as opposed to the DC. I was not sure how much an issue it would be.
I am lucky enough to have plenty of varied breeze so I want to try different configurations and learn more. I will pick up some F&Ps and learn about re wiring them.
davoone day oil, coal & gas will eventually run out...
wind and sun are here forever.
hello...?
frank133 Newbie Joined: 11/09/2008 Location: Great BritainPosts: 32
Posted: 08:53pm 17 Sep 2008
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Hi Gill,I have been going down the same route as davo,
Making the blades first,all out of pvc,I have made about twenty up to now.[not a great success,.
So I made the tail ,and have been involved in making the
swivel,for the motor to sit on the mast.Its looking good so far,its a double bearing,so with a bit of welding tomorrow it will be sorted.
IT might never produce any electricity at first but it will look cool.still trying
GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127
Posted: 11:35pm 17 Sep 2008
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Hi Davo,
The voltage drop is proportional to the current and the wiring resistance. AC does not actually make the best use of wire, whereby pure DC does. AC is easier to transform to recover the transmission voltage loss in the power reticulation system.
Hi Gordon,
Thanks for the reply, so from an efficiency point of view under what circumstances would you recommend using AC or DC? Ignoring the need for two/three wires and slip rings etc.
rgds davo
one day oil, coal & gas will eventually run out...
wind and sun are here forever.
hello...?
Hi Frank,
what sort of problems are you having with the pvc blades?
rgds davoone day oil, coal & gas will eventually run out...
wind and sun are here forever.
hello...?
GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127
Posted: 12:43am 18 Sep 2008
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Hi Davo,
This has been discussed before on this forum.
The most efficient use of a piece of wiring is when the average current flows 100% of the time. This can only occur with well filtered DC, or Square wave AC of 50% duty cycle.
Pulsed DC,or AC, and Sinisoidal AC does not have this quality. In some instances there may be other benefits for sinisoidal AC. Pulsed DC and AC usually causes many other electrical problems, so is avoided in power transmission systems.
In my F&P windmill system, the 3phase wild AC is transmitted in twisted wiring and inside the steel pole. The rectifiers, maximiser and large filter capacitor [6600uF] is close to the base of the pole. the DC, proportional to wind energy, is fed to the loads at a constant voltage.
In my Axial flux system, The 4phase wild square wave AC is rectified and lightly [1uF] filtered in the windmill yaw box. varying voltage DC, proportional to the wind energy is transmitted in a double twisted pair to the Maximiser. The maximiser has 10000uF input and output capacitors. DC power from the Maximiser at constant voltage and current proportional to wind energy is transmitted to the load in twisted pair cable.
I have used different techniques on each system. The longer the distance, then current is not your friend. Usually a higher system voltage overcomes the wiring problems. 12V power systems are critical with wiring losses.
The pulsed currents with battery loads can interfere with radio and TV reception.
Keep the wiring with pulsed energy lines short and rectify close to the source. Use filter capacitors close to the rectifiers. At maximum mill rating, 3phase rectified is close to pure DC when filtered. At lower power levels, the 3phase rectified output becomes pulsed DC. Efficiency usually comes with a spark when large capacitors are connected in a battery system. Adequate switching and fusing should be employed.
I keep the wiring loss to a minimum. I use recycled wire of a size I can still terminate, to keep the cost down. If you have to bury the wire, then I would use double insulated new wire and conduit.
Skimping on wire can be a cause machine runaway during storm events due to additional voltage drops at higher currents.
Thanks Gordon,
awesome... I have a lot to learn. I will read more of the past forum.
rgds davoone day oil, coal & gas will eventually run out...
wind and sun are here forever.
hello...?
frank133 Newbie Joined: 11/09/2008 Location: Great BritainPosts: 32
Posted: 08:17am 18 Sep 2008
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Hi davo,the ones I have made up to now,will not turn in the wind,they are mounted to a dc dynamo,with no load on it,the blades turn by hand with no resistance,I have balanced them with the blades hanging from a piece of string,
The best success I had was six blades bolted to a car fan,I have been using 4"pipe cut in half,and the blades are 2 foot long,
I must be getting the angle of attack wrong,
I have made three mounting plates for the blades,a 2 a 3 and a four blade,I have tried them all I am now making the mast head to fit the dynamo to.
I have read every article I can find on pvc blades,
But I must be making the same mistake each time,
which part of the blade is the most important the root or the tip,
I read somewhere that on a three bladed prop one blade can have the trailing edge the opposite way around,
I am using a dc motor,and am getting 80v spinning it by hand,but 5v when connected to a 12v battery,[I think]
Best of luck with your project mate cheers frank.
The best success I had was six blades bolted to a car fan,I have been using 4"pipe cut in half,and the blades are 2 foot long,
Hi frank,
I do a lot of sailing so I know what I want it to look like.
Have a look at this guy on youtube it will be a good starting point.
http://www.youtube.com/watch?v=s75-lCKKK8g&feature=related
cheers davoone day oil, coal & gas will eventually run out...
wind and sun are here forever.
hello...?
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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