 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. |
Forum Index : Windmills : My plan: a rig for "extreme" conditions
| Author | Message | ||||
| tomasp Newbie  Joined: 20/10/2006 Location: New ZealandPosts: 28 |
Hello all. I have a site in a valley on the foothills of the ranges in the "roaring fourties". It is pretty much always windy, gales and severe gales visit the place very often too. My plan is to build a "tough" genny for those conditions. To make things even more crazy I want to build it without any furling system. That means the tower and the genny chassis must be strong to withstand 80-120km/h gales. For the same reason I think NOT to rewind F&P motor in order for it to be designed for high RPMs. In order to squeeze maximum of the juice I want to gang 2 F&P motors with an offset as brucedownunder did to avoid cogging. Using those high speed "hornet" blades should do the trick - by the way did you see www.survivalunlimited.com? That guy is selling turbines for extreme winds and it looks like they work ever through cyclones - kind of inspired me too. I think for a test rig I might even use PVC blades, maybe reinforce them with fibreglass or glue 2 of them together for stiffness. I want to build it to be tough, i.e. all steel welded body with stainless steel cover over F&P motors. Ideally I would also want an aluminium motor hub  but I guess it will have to wait some time...
The power will have to be transported at least 75-100 meters from the tower thus the idea is to use unrectified AC for that. I will also build a smart controller to switch between star and delta also to switch dump load(s) etc. So - what do you guys think? What should I be careful about when building a high speed turbine for extreme conditions  |
||||
Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Sounds like you have tought it through. Those little hornet blades do work better in high winds, but they can get noisey. Have a look at my windmill design here, its very rugged. I took mine down a couple of weeks ago, and after 15 months up in the air its in excellent condition, no need for any maintenance at all. Also check out the cogless 7 phase conversion here, might save trying to align a couple of F&P to reduce cogging. I would still use furling myself, even if just to save on bearing wear. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
||||
| tomasp Newbie Joined: 20/10/2006 Location: New ZealandPosts: 28 |
Thanks, Glenn - I have already studied your design many times, it gave me a few good ideas. The reason I want to use 2 motors (actually, wanted 3 but decided to start with 2 for starters) is to extract more watts. The problem with furling for me is that there are no definite formulas/calculations to calculate the tail size/weight/angles etc. - if I had some then maybe a tail that furls on say 90 km/h wind wouldn't be too bad. But then again - is that worth it, or even possible, i.e. has anyone had any system that furls in very strong winds, as opposed to just strong? Maybe something is different - I don't know.. |
||||
makourain Senior Member  Joined: 19/04/2006 Location: Posts: 111 |
maybe you should consider a hawt  |
||||
| tomasp Newbie Joined: 20/10/2006 Location: New ZealandPosts: 28 |
You mean "vawt"? :) I don't know - they seem to be bulky and high maintenance. I think hawt is better for higher speeds than vawt - vawt would have to very large not to overspeed and self-destruct where the site is...sometimes the wind is so strong that is it actually hard to stay vertical...our neighbour was unloading her car and stepped out of the shelter of her house into the win. The gust caught her glasses, ripped them off of her nose and she has never found them again :D You get the idea :) It's not like it is blowing this hard ALL the time but I would be reserved about a large vawt in those conditions... |
||||
| tomasp Newbie Joined: 20/10/2006 Location: New ZealandPosts: 28 |
Been thinking more about this. I should probably build it without tail or furling, fixed direction. Where it will be sited is quite narrow valley (1 km or less wide, I'd say) and the wind 95% of time blows from the hills. Really, would that work or do I still need furling system? 2 F&P motors with 4 double thick PVC blades encased in fibreglass fixed to face one direction only - is that crazy or not? |
||||
| maaca Newbie Joined: 21/11/2006 Location: New ZealandPosts: 22 |
Hi Tomasp,What part of the country are you in?. I am in the same boat as you. I am over on the West Coast where the SW winds are normally somewhere between 30Kph on a good day and up to 80Kph plus on a windy day.I am going to build a wind generator early next year and have the same concerns as you.I too will use a F&p, but a single version mounted on a 200mm wooden pole and on a sand dune believe or not Around Two hundred feet above and over looking sea level.What progress have you made so far. I wish to make my own wooden blades and a few days ago found a great web site with very detailed plans for a 2.4mtr prop but I forgot to save it.Can any one help here?.Many thanks Maaca. |
||||
| tomasp Newbie Joined: 20/10/2006 Location: New ZealandPosts: 28 |
Hey maaca, we have some land in Wairarapa, on the foothills. Your spot is probably even better :) I have a couple of motors sitting on the bench, got myself a mig welder but need to get a wire feed motor for it first. Will start building sometime early next year, like you. If you want wooden blades, maybe they were on www.scoraigwind.com? I think I will try PVC first, but will try making thm strong. be careful with the size of the rotor - 2.4 may be too big for high winds - it can destroy itself. My understanding is that smaller prop with more blades will actually protect itself better from overspeeding. Have a read about that! |
||||
| maaca Newbie Joined: 21/11/2006 Location: New ZealandPosts: 22 |
Thanks Tomasp, Well you sure are in one of the windy spots thats for sure.I take your advice on-board.I have ordered a book from Hugh Piggotts web site so will study that on arrival.Also ordered a book on F&P motors from EcoInnovation in NewPlymouth.I guess we are a bit spoilt as we can go to any recycle cenre and pick up an old machine for vurtually nothing.Only have to pay when you take the stupid remains back.Will contact you again in mid to late January and compare notes.Many thanks Maaca. |
||||
| thefinis Regular Member  Joined: 23/08/2006 Location: United StatesPosts: 53 |
You might want to consider downwind blades in that kind of extreme weather. At least then if you get flex or failing blades it will take it away from the tower and alternator. Just a thought Finis Texas born and bred |
||||
| maaca Newbie Joined: 21/11/2006 Location: New ZealandPosts: 22 |
Thanks Thefinis, Down-wind was something I had'nt even thought about. To be truthfull didnt even know much about, so did some quick research on the net and I think you are right, its something I certainly will consider.Perhaps some-one else might like to view their thoughts. Maaca. |
||||
vawtman Senior Member Joined: 14/09/2006 Location: United StatesPosts: 146 |
|
||||
| vawtman Senior Member Joined: 14/09/2006 Location: United StatesPosts: 146 |
Sorry tomasp my daughter kicked me off the puter before i could finish(women goodness) 
Ive been wanting to build a rooftop turbine and dont think my darrius will run smooth enough no matter how many blades i use. Then i got to thinkin why not build a big attic ventilator,Should be very little if any vibration issues because of the many blades.Planning on using pvc pipe cut in thirds lenghtwise for the blades. Maybe an idea for ya since it shoulnt overspeed and will work in swirly winds. Planning on starting this weekend making a 4ftdx2ftL for testing then i could stack more in the future.  |
||||
 Print this page |
