I noticed a wind turbine in B&Q, and it is nothing more than a motor, on a pole with a propellor and some box of electronics.
How are these valued at over =A31500 when it seems it can be made for a fraction of that? How much would the parts be?
dg
The value is what people are prepared to pay. It has no connection with the cost of the parts.
Not much if you make a savonious rotor with an old oil drum.
Owain
They are not *valued* at £1500 at all. The price charged is what they believe sufficient people will pay to justify the shelf space. It also gives them plenty of room for manoeuvre when the inevitable happens and they don't sell. They could probably knock 60% off the price and still make a reasonable margin,
Also, AIUI, the price includes a survey and fitting.
It's also the cost of R&D. Try making your own - go on!
Mary
What R&D?
The motor seems to be some off the shelf model and the propeller, well same as those on some 1850 farm bore hole.
The only thing to be 'developed' may well be the electronic box, but that I presume would be a basic convertor circuit, again nothing new.
dg
What R&D?
The motor seems to be some off the shelf model and the propeller, well same as those on some 1850 farm bore hole.
The only thing to be 'developed' may well be the electronic box, but that I presume would be a basic convertor circuit, again nothing new.
dg
For a good web article on DIY that's about as DIY as it comes, read the design and constructional details on building one from a Volvo 240 front strut
Plenty of R&D has already been done on DIY wind turbines, and plenty of plans on the net. Trouble is the effort probably isn't worth it for the small outputs that you are going to get from an turbine you can construct at home without specialist kit.
As I see it wind is not really the way to go. To get sensible outputs you have to have huge devices(*) that on average only generate 1/3 to 1/4 of their rated output over a year.
In the relative scheme of things as well not just the rotating jumbo jet on a pole 2MW commercial turbines. Even a small 2kW "domestic" jobbie has a rotor around 2.5m in diameter on top of pole at least 5m high. And note that those powers are peak powers not what you'll actualy get most of the time.
Small turbines with rotors less than 1m in dia generate no more than a few hundred watts OK for battery charging on a boat when the boat isn't in use but for a house not worth it. To put this in perspective, a 500W or so wind turbine couldn't keep a large battery bank charged in the long term to power 3 Cisco wireless bridges, a router and switch. And this was on top of a hill with good exposure to strong winds...
What did you do instead?
Went bust I should think, or dug some cable...
Definitely micro windpower is a waste of time and fossil fuels.
You would be better off making a small steam engine and burning your rubbish.
Hmm...that IS a thought actually..and an electric fan once it gets going to 'turbocharge' the boiler..
"nightjar .uk.com>"
If it's so easy I wonder why aren't people doing it ... or perhaps they are and are keeping quiet about the results :-)
Mary
Its a bit more than that, though not a huge amount. The motor has to be a type that offers near zero starting torque, which rules most motors out. It also has to be one where low speed can produce the wanted output, which again rules many out. It also should preferably be PM field to avoid losses, though there are some excited field gens around.
Standard PM field motors dont start effortlessly, so no off the shelf motor satisfies all the requirements. However if you want to make a no-cost compromise design, a car alternator is a fairly good choice. The controllable field makes it more efficient at higher speeds, as you can reduce excitation to reduce V_out. The downside is at low speeds a significant amount of your output is simply supplying the field coils.
theyre priced at 1500, the miniscule sales volume shows that theyre not valued at 1500. The price comes from business costs, if you only sell
10 units a year you have to divide your total biz costs by 10 and add that to the price of each unit sold.=A350 should cover it. Car alternator, wood or metal for the prop, steel pole, brake drum for the rotating mount, some control electronics, tailfin assembly, overspeed brake, service brake, and rotatable power conductor. There are lots of plans around for making them from scrap.
NT
Have you ever seen such a thing do more than power a lightbulb though? Propellors beat a Savonius design every time, for any load bigger than a spinning advertising sign
(yes, I've built several of both)
Because by the time you take into account the miserable amount of power available and the cost of a large bank of batteries to store it (and their periodic replacement), it works out several times the cost per unit compared to buying electricity from the mains.
Self-generation is usually only viable if
- you cannot get mains electricity installed, or the cost is prohibitive
- you have combined heat+power (and that is usually for part-generation only anyway)
- you generate from waste material such as old engine oil or chip fat and have a very cheap or free source of such material, or even better have a cost-to-dispose of that material
- you have a private hydro-electric plant with sufficient stored water to avoid the need for battery storage (hydro-electric plant needing comparatively little maintenance)
Owain
Spent =A32,000 with the local power company for a mains conection at the= TV transmitter a couple of hundred yards along the hill top. ISTR that that=
2k was just for the connection though may have include the cable. We use= d a local contrcator to dig and fill the trench.Another site with two large solar panels (2' x 5' approx) and wind turbine couldn't hack it either. Tea leaves helping themselves to the panels didn't help that site has been abandonded.
It's worth noting that both sites had winds sufficient to break three turbines in total. One was supposed to be rated up to 120mph or so...
The message from snipped-for-privacy@codesmiths.com contains these words:
Those spinning advertising signs are sodding dangerous. I saw a toddler get his head seriously smashed by one once. Just toddled into it on a windy day. Some of them are very solidly made and have considerable rotating mass and no apparent overspeed braking.
Come to think of it, I haven't seen one for quite a while.
I was going to comment that some railway trackside equipment uses solar panels ...
... and that they weren't very well guarded if some dishonest soul wanted to experiment :-)
Owain
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