Wow! Thanks for the replies, guys.
Dang: Yes, while fiddling with a stack my finger got pinched. Yes, it hurt. Lesson learned. I will only work with one magnet at a time. The stack will not be anywhere near the work area. I’ll also need to work on some way to anchor the rotor while working on it. I don’t need tools and parts to go flying around the shop unexpectedly. The shop vac is my friend. The magnets are back in the bubble wrap and box, they were only taken out for the photo op and inspection.
Woof: I ordered enough to make two machines. I just know I’m going to mess one up someway, somehow. It’ll happen.
Watt: Thanks a lot. This is what I really need, some rules-of-thumb to base starting points on. The parameters I started with had no basis in fact, just some assumptions I’ve made based on the descriptions of other projects. I assumed a spacing of one magnet width, maybe a little more. My plan is the first device will use 8 magnets per rotor, 16 total. Yes, it will be three phase. I’m trying to follow common practice, not blaze new trails. This first machine is a learning laboratory for me. I’m hoping my expectations are more conservative than overly optimistic.
Janne: More rules of thumb. Many thanks. That’s really what I need, critique of what I’ve set out to do, suggestions to avoid mistakes and to define reasonable expectations.
Ross: Thanks for forwarding the info on to Flux. Please pass along my appreciation for him taking the time to help me out. Of course the parameters set out above are just a starting point and will be adjusted as warranted. A 5 foot rotor is do-able, I think. 7 foot will likely start running into issues with the neighbors (not to mention the county bureaucracy). More than that and I’ll start running into structural issues and trees. Though something tells me my wife will start complaining before any of the above get a chance to
Bj: Thanks for dropping by. I don’t know about addicted (yet). But it is something I’ve wanted to do for a very long time. I have a smallish machine shop in a corner of the garage: 7x14 lathe, 9x20 lathe, X2 type bench mill and a larger knee mill. I also build small engines: steam, stirling and repairs around the house. The plan is to document the project here. Perhaps some other newbies will find it useful.
By the way, this is likely to be a slow build. Time, materials and motivation may not always be available at the same time. I'm on call 24/7 and of course family needs always come first. I have the motivation and would like to be flying ASAP but a more likely timeline is first wind around mid to late summer.
OK, design changes:
5-6 foot turbine, but I still want to get away with as small as possible.
Cut in ~300 rpm
Hub 8 poles, 6 coils, 6-7 inches in diameter
Bearings yet to be determined.
Wire gauge and turns yet to be determined.
Any suggestions on bearing size or style?
Coil:
I’ve read where the core should be the same size as the magnet. Is there and advantage/disadvantage to going slightly larger or smaller? Is wider better than longer?
Is there any advantage to building a pair of small test rotors first, say with four poles to help determine what coil parameters to use?
Thanks,
Kevin