I've also been working on some parts for a sort of 'kit' - or at least parts to make assembly easy and a nicer looking machine hopefully. Depending on the magnets we use, and how we wind the stator I think this 'platform' is good for 8 - 11' machines. A freind I met over all this wind turbine stuff (Art Randolf) is making pretty neat fiberglass reinforced nylon blades and a variety of hub options that he'd like to sell. I've been wanting to build a machine to test these on now for over year... finally got around to it. This will be an 8' diameter wind turbine. Pictured above is the 'magnet rotor' - it has 12 of those wedge shaped magnets. As usual, the rotor is mounted to a trailer hub, the bolt pattern is 4 holes on a 4" diameter circle... pretty standard. The magnets are segments of a ring such that 24 of them will form a ring 12" OD and 8" ID, they are 1/2" thick. They seem to perform almost exactly the same as the 2" diameter X 1/2" thick disks I've used on past machines (so with the same stator we could use either magnet and expect very similar results). They cost about the same as well. With 2 disks loaded with these magnets, we seem to have a pretty reasonable 11' machine (10' machines will stall a bit) - some folks up here have put 12' props on them. Im shooting to run a single rotor here and hoping it will match up nicely with this 8' blade set.
... yes, thats right, a single rotor - with no laminates or anything on the back side. It's not 'proper' - and not the best use of magnets, but on the other hand, if it works out, it's very easy to put together, very easy to adjust. The extra we might spend in magnets is offset by the savings in time/money involved with a 2nd rotor. The magnet rotor lays flat on the trailer hub, the stator sits right behind it.
We figured.. since the stator will be very visible from one side.. we should try to make it look cool. Here's our first ever 'designer tie die stator'! Its got 9 coils wired in star, the coils are wound with 55 windings of #13 wire. Cutin speed with the single rotor is 180 rpm. The resistance may be too high - she might overheat, time will tell. If that is the case, Ill rebuild the stator with fewer windings/heavier wire and probably go to running with a blank steel rotor on one side of it.
Here is the alternator assembled. I could've put the magnet rotor either on the front or back of the stator. On the front there doesnt seem to be any noticable attraction to the stator brackets (if there were I'd turn it around). I like the look of it better on the front... it might cool slightly better if it were on the back. I think it probably doesnt matter either way.
Here are Art Randolfs blades all painted up green. The hub he provides makes this an 8' machine, and the hub fits the bolt pattern perfectly. This setup is also probably quite suitable for use on Hugh Piggotts 8' axial flux machine. My only concern about these blades is their flexibility... we'll need some clearance between them and the tower. They may also flutter and make a bit more noise than the wooden blades I'm used to. But - in their favor, they are very tough - you cannot break them. I have no doubt they would survive striking the tower at very high speed. They are also fairly inexpensive.
These are the steel hub pieces I normally put on both sides of the wooden blades. With Art's blades its not necessary - the hub is very strong, but it looks nice with these on both sides.
Here we have Art's hub sandwiched between the two steel pieces and bolted to the alternator. The plastic hub (fiberglass reinforced nylon) come in two halves, and the blades slip into holes. It goes together very easily.
Here I've stuck the blades into the hub. You can see the twist/taper in Art's blades. They look very workable.
There it is almost finished up! We'll probably complete this machine on Monday, then we'll finish DanF's tower at his house and test it there for a while. My bet is it'll work OK if the stator can take the heat!