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Forum Index : Windmills : My DIY Savonius
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| Ghetto Newbie  Joined: 01/09/2009 Location: AustraliaPosts: 14 |
Hi Everyone, Thought I'd post my urban sized savonius I've been constructing. I live in a city with a 10 square foot backyard hence the size of this thing to suit. Eventually I will move back out to the country and then i can get serious about building something bigger. Its pretty crude I know, I have minimal tools and built it for proof of concept but also practical use. Rotor made from 8 inch gal flue pipe from BBQ's galore, cheap pine from bunnings. Runs on skate bearings. My aim is to trickle charge a 12 volt battery. I realise I have stuff all surface area (I've done the calcs) but would be stoked if I can jag 14watt at 25 km/hr wind for example (ie 14 volts @ 1amp). I'm not aiming high here. I now need to do the electrical generation part. Initially I'm directly connecting an AC stepper motor and see how that goes. I swear if I had another tier it would run my f&p 60 series stator unmodified but guessing its too small as is. Currently saving up hard drive magnets to build a dual rotor air core axial flux (based on advice oztules gave someone else re: vawt generator design). 
Likewise we had a windy day on saturday so I dragged it out for its first test run: http://www.youtube.com/watch?v=QyT4muL1WJ0 About 35 seconds it reaches max RPM, it gets along but obviously this in an unloaded speed; don't think it will go this fast once I'm generating power from it. I feel it goes better than it looks :) Top brace is a worry, will have to revise that, too much flex...will probably change it for something stronger/different design even. I probably should of had round end plates which would improve its balance but really would need another tier 90 degrees to truly balance it unless I put weights on the current setup... Kinda feel like its the same category size wise as the jaycar savonius recently discussed here. Anyway just thought I'd chuck it up here and share, I do a lot of learning lurking here (past 2 years straight) but don't have much to contribute as i don't know what I'm doing compared to the regulars who know their stuff :) Cheers, Rob |
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| VK4AYQ Guru  Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Ghetto The main thing is you have made a start as everyone has to do. It looks big enough to do one amp if your stepper motor will do it. only thing the steppers I have are bad at coggining so hard to start, I ended up using a per mag car fan motor that was drawing 4.5 amps and it generated 1.5 amps into a 12 volt battery. All the best Bob Foolin Around |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5124 |
Hi Rob Well I think it looks and runs great. I love these little builds, lot of fun. A big stepper motor would work perfectly well, but yes a axial flux would be the way to go. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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wind-pirate Senior Member  Joined: 01/02/2007 Location: CanadaPosts: 101 |
Great Start Rob 
You will need to make a stronger frame, when you add your generator. Smaller Diameter mills turn faster "But" with less power, so you (might) need to go for more height. Make sure you get the mill up in the wind. V.A.W.T's need wind too. "You will be suprised at what it can do".. Ron. THE Pirate. stealing wind & solar energy is fun |
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| Ghetto Newbie Joined: 01/09/2009 Location: AustraliaPosts: 14 |
Thanks guys for the positive feedback and encouragement. I really appreciate it being a newbie. 
Them steppers do cog for sure, so its an experiment. I'm going through the mind frame that I need a decent wind to generate power so if it doesn't start up in lower wind speeds due to cogging its probably no great loss as there's no decent power to extract but on the other hand I know that thinking is flawed and that we're always trying to maximize total power/efficiency where possible and hence why I want to try an axial flux. Definitely will sort out that top brace before its running 24/7. I really do want to get it up higher, I'm going to have to work out what the best solution is. Been though the beginner phase of thinking VAWTs make great power at ground level. Like you say Ron, they benefit from height the same way HAWTS do. higher wind speeds and "cleaner" (less turbulent) wind. Cheers, Rob |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Getto You are on the right track so if you can get it higher it would be good try to make it fit on a length of 2" water pipe as that's a cheap mast with some guy wires, Paint the whole thing green and it will be hardly noticed on the skyline. All the best Bob Foolin Around |
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| wind-pirate Senior Member Joined: 01/02/2007 Location: CanadaPosts: 101 |
Hi Rob I have about 10 small steppers. And yes they "ALL" cog. But once they break lose the will give power. Most mills need about 10 mph/16 kms to give much return. so the more wind they get, the better. A word of caution, Wind mills can be adictive. Don't give up, Just make changes. Ron. THE Pirate. stealing wind & solar energy is fun |
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JimBo911 Senior Member Joined: 26/03/2009 Location: United StatesPosts: 262 |
Mr. Ghetto Great job my friend. Look at that thing spin. Keeps the neighbors wondering.  Jim |
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