Low RPM generator help please

[aamcle]

Hi.

I'm working with a small charity in the UK and we are hoping to build a wind turbine but we need to have it cut in at low speeds and would like an out put of 800w.

We have the opportunity to test it in a Hydro set up thus the need for power at low speeds.

I have Hugh's book, it details Power vs  Wind Speed not generator RPM , how fast are Hugh's generator designs meant to rotate to achieve full output?
 
The 3000mm and above look as if they should work depending on the RPM they need, can you advise me as to the best choice?

Another generator set up I've seen is produced by markp0177  and shown on YouTube :- 

http://.youtube.XXX/watch?v=lbpRdme4Tpg&feature=plcp {I don't know if it' OK to post a live link so you will need to swap the XXX for COM}

The Coils mounted vertically in a thick ring stator with the magnets (28 of them) rotating around the outside of the ring. Oddly it's apparently 2 phase so I'm thinking 20 coils, 10 for each phase.

It seems to be what we want but it's difficult to make as we don't have a lathe, do you know if it actually works?


Many Thanks           aamcle

[Flux]

Where to start?

You want a wind turbine but you want to test it in a hydro set set up? You give absolutly no details of the hydro, its speed or anything else. You say you want 800W, is that for the hydro?

With wind you don't get 800W except momentarily, do you mean a nominal 800W machine?

Hugh's book gives power versus wind speed for good reasons, that is how wind works. When you have sorted out your basic wind issues and arrived at a size of turbine for your needs then you are in a better position to think about rpm.
If we think about Hugh's 3 m machine then it will start producing power in the 120 rpm region and at a complete guess I suspect it will need to be turning at something like 350 rpm to produce 800W.

I haven't looked at your youtube link, I might have done if I could just click it but there are loads of things on youtube some good and most useless so I am not sure how useful it will be. If you have no machining facilities you are more or less stuck with a simple design such as the axial air gap machine, that's one of the main reasons why Hugh has developed them.

If you come back with some finite details such as the speed you want to use then it would be a lot easier to give an answer and it would help if you could decide whether you want hydro or wind, unless the hydro speed is compatible with your intentions for the wind turbine it would seem a pointless exercise testing a wind turbine alternator on hydro as the requirements are different.

Flux