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gotwind
Forum Admin
United Kingdom
1565 Posts |
 Posted - 16/06/2009 : 21:52:31
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Simply due to the costs involved compared to China prices.
Neodymium magnets in the U.K alone would cost £40-£50 for a 100-200 watt alternator - 4 ft diameter prop maybe.
Enamelled copper wire, another £30
Plus shipping, we're nearing £100 ($165).
This is before blade manufacture, slip rings and mountings..
As we know, there are Chinese imports that are of a similar spec available for £260 ($400) - the conversion rate isn't favourable at the moment. Navitron sells such small turbines.
http://www.navitron.org.uk/product_detail.php?proID=193&catID=69
My latest idea here, a single rotor axial flux design, Like Hugh Piggotts, but using a triangular shaped coil winding.
I've done my best, spending weeks trying to utilise readilly available components for steel rotors (cookware, pizza trays, bake trays), bearings (bicycle hubs) e.t.c
It's very difficult to beat mass volume China prices, however it is certainly enjoyable for me trying in a DIY fashion and a lot greener from an importing perspective.
I won't give up, it's just a bit tougher than I thought.
Ben.
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Capt Slog
Junior Member
United Kingdom
262 Posts |
Posted - 17/06/2009 : 10:18:18
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I had the same problem when i wanted to build mine; the prices looked to be prohibitive.
So I went for round magnets to get the cost down and they came from the USA when the dollar was struggling. They were bought by a colleague's father whilst over there on business and came back in a suitcase. I managed to get 26 magnets (24 needed plus 2 spares) for about £1 each! These were 1" diameter x 3/8" high N42, very strong too.
I have seen comparable magnets from some place in europe, and the shipping isn't too bad either, I haven't been able to find it on a brief search, but I'll let you know if I do.
The advantage of using round mags is that you can also make the coils round too, thus saving on copper wire. I believe the power loss isn't as great as you'd think. I bought two rolls of 1.25mm diameter enamelled copper for around £15 (can't remeber the size of roll though, could have been 1kg?). I had more than half a roll spare.
The steel discs for the rotors I had supplied and cut by a local engineering firm. The manager was good enough to tag my job onto another one that he was sending out to a third party and charged me just £20 for two 6mm thick discs 210mm diamter with a central hole. You can get lucky, especially if you're willing to tell them what you're doing and talk a bit.
The result was a 12 pole 9 coil alternator, which runs ok. One day I'll have the time to get just the right blades on it, and then the bugger will really start to pump it out!
EDIT. I've just been looking at the prices of neos. They seem to have gone up, a lot!. Ok they were never cheap but my suggestion of more poles/smaller mags works out at around the same prices. Sorry Ben, I think you're stuck with paying through the nose for them.  |
Edited by - Capt Slog on 17/06/2009 11:08:19 |
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jonnny
New Member
United Kingdom
68 Posts |
Posted - 17/06/2009 : 18:46:50
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| Hi Ben if you need any rotors turned, just let me know,Jonny |
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gotwind
Forum Admin
United Kingdom
1565 Posts |
Posted - 17/06/2009 : 19:40:10
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Thanks Jonny,
I may well be requesting something soon, circular this time.
Cheers.
Ben. |
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ghurd
Average Member
USA
546 Posts |
Posted - 17/06/2009 : 22:14:02
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I know what you mean!
I tried to get specific bearings, nothing special but the ID/OD which was nothing custom, about like bicycle bearings, and they wanted $60 (£36) for a pair.
That's why I like induction conversions. Bearings, wire, etc are included. Not a perfect solution, but inexpensive enough I can play and eat on the same day.
G- |
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gotwind
Forum Admin
United Kingdom
1565 Posts |
Posted - 03/07/2009 : 22:23:04
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Hi jonnny.
I have just emailed you, requesting an 8 incher 
The diameter of mild steel rotor plate for my new DIY 200 watt alternator axial flux idea 
Cheers
Ben. |
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jonnny
New Member
United Kingdom
68 Posts |
Posted - 04/07/2009 : 06:12:27
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| Hi Ben i have not recieved you email for some reason,send me a private message. Thanks Jonny |
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gotwind
Forum Admin
United Kingdom
1565 Posts |
Posted - 04/07/2009 : 09:00:30
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I have Pm'd you Jonny,
Just in case
Hi Jonny.
Are you available to turn me a single mild steel rotor disc for my latest DIY alternator idea? a 200 watt alternator achievable by most people.
It would need to be 1/8 (3mm thick) mild steel plate as flat as possible.
8 in diameter with a 3/8 central hole not that easy I can appreciate, please dont feel obliged to make it, only if you can.
Cheers.
Ben. |
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jonnny
New Member
United Kingdom
68 Posts |
Posted - 04/07/2009 : 15:27:07
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| Hi Ben I can turn a rotor for you ,but I can't garentee how flat it will be.It all depends on how flat the metal is when i buy it .Its difficult trying to face thin steel its to springy,and of poor quality.You may stand a better chance of it being flat by useing thicker steel. Let me knowe watt you think, Jonny |
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gotwind
Forum Admin
United Kingdom
1565 Posts |
Posted - 04/07/2009 : 15:47:58
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Hi Jonny.
I guess we can go up to 3/16th thick, 1/4" would be too thick, see what you can do please.
Cheers
Ben. |
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gotwind
Forum Admin
United Kingdom
1565 Posts |
Posted - 05/07/2009 : 16:21:03
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Hi Jonny.
can we make it 9" in diameter please.
My coils have come out a bit larger than expected.
Cheers
Ben. |
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jonnny
New Member
United Kingdom
68 Posts |
Posted - 07/07/2009 : 13:27:52
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| Hi Ben I will have a go,i will try to support it with some sort of back plate to stop it from flexing,and try to machine 1 side flat .Wont be able to look at it untill late next week when im back working days.Thanks,Jonny |
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gotwind
Forum Admin
United Kingdom
1565 Posts |
Posted - 07/07/2009 : 18:32:48
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O.K thats fine jonny, just do what you can please.
Thanks.
Ben. |
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jonnny
New Member
United Kingdom
68 Posts |
Posted - 21/07/2009 : 23:25:09
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| Hi Ben sorry ,iv been short on time of late ,nearley done your saw blade ,just got to make the center bush.Do you want it sent to your company address or home .If home you will have to email your address as all your details are on my old pc. Thanks, Jonny |
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gotwind
Forum Admin
United Kingdom
1565 Posts |
Posted - 25/07/2009 : 17:10:47
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Hi Jonny
I have PM'd you, a few days ago, hows the rotor progress coming along?
If you didn't recieve it, you can contact me directly.
ben[at]gotwind.org
Ta.
Ben. |
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jonnny
New Member
United Kingdom
68 Posts |
Posted - 25/07/2009 : 23:35:42
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| Hi Ben it will be in the post Monday.I tried to weld the center bush in,but ended up blowing a small hole in it,it will be ok just looks a bit naff.Thanks,Jonny |
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Topic |
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Guys I'm struggling with the latest DIY alternator