Wasn't the aim at the beginning to improve on efficiency and materials compared to the more 'traditional' dual rotor axial flux air core alt?
Well, realize I'm not done with this project - in fact, I'm just getting started. And to do some experiments with single rotor air core units, since I already have one built, I'm going to use a "traditional" axial with one rotor on it. I just got done bolting this thing to a turbine head so I can run it with my hydraulic motor setup and get some data on flux thru the coils vs performance that I know I get with dual rotors. I set the gap between the magnets and stator to the thickness of a piece of newspaper (~.0025") for the initial run:
I'm going to try various materials to complete the flux path, from a blank steel disc rotating on the shaft with the mag rotor, to a powdered iron core bolted to the stator, etc., to see what I get. Using the axial I can do this without having to rewind the stator every time I want to try something new. But the data I get from this experiment can hopefully be applied to the radial build.
I may still proceed with the powdered iron core once I figure out what it takes. Or I may not. Like I said, I've only just begun this project and it's one of the most fun and interesting ones I've done.
"No one smirk out loud now, please."
Smirk away all you want - I see a lot of talk here on Fieldlines but not many people actually doing much building. Ed Lenz from-scratch built a 4 pole radial air core once that fits in the palm of your hand and puts out 50 watts (
http://www.windstuffnow.com/main/radial_air_core_alternator.htm):
Unfortunately, Ed doesn't post here anymore but he has a website where he puts this stuff for other people to look at. I don't. But maybe I'll start one because I've experimented with at least as much brainstorm stuff as Ed has - and like Ed's experiments of the past, some of it works, some of it don't. But there's a lot more people who read the information and find it useful, failure or success, than there is that comment on it. And that's one of the aspects of building homebrew turbines - sharing ideas on builds with other people.
That being said, this will probably be the last post I make here on the topic - in the mean time (until I maybe put up a website with all my experiments on it) I have a Google album thing where I'll post pictures and explanations of the continuation of this project. That album thing is located here for the people who are interested in it:
http://picasaweb.google.com/christopher.w.olson/TurbineGenerators#For ghurd - yes, I ran it first with one phase, then pulled the stator and wound all three phases with a spool of AWG 18 wire I found. The 39 volts I got was all three phases in star (phase 2 is reversed in this configuration so it either has to be wound backwards or reverse the start and end of the winding). It should've been around 19 volts. The individual phase voltage came in around 20-21 volts @ 100 rpm. The picture I posted last night was one I snapped when I was aligning the stator to the rotor, then the batteries in my digital camera went dead but I was able to retrieve that picture off the memory card in the camera.
I initially wound one phase and two coils on phase two but ran out of wire to complete the second coil. So I unwound that coil, soldered more wire on from a spool of AWG 18 I found in a box and finished winding the whole thing for testing. One of the other purposes of that was that when I unwind it I can stretch all three wires out from the phases and see how close they come to the same length. Theoretically they should all be the same, but the way the overlapped coils are layed out, phase three ends up with slightly shorter winding heads than 1 & 2 because the winding head goes slot to slot instead of bending around the legs so the other phases will fit. I don't expect it will be a lot - maybe 6-8" in total. But it was one thing I wanted to know.
As far as the motor conversion comment - for people who like to convert electric motors to generators that's good - and I suspect the late Wayne Abraham (Zubbly) was the resident expert on the topic. But some of us like to figure out how to build stuff from scratch.
--
Chris
