alt.energy.renewable

On Sun, 09 Sep 2007 09:31:28 +0100, Eeyore
wrote:

>
>
>Mauried wrote:
>
>> Eeyore wrote:
>> >Mauried wrote:
>> >
>> >> Most Windmills Ive looked at include a Charge Controller of some sort
>> >> that produces DC suitable for charging a set of batteries.
>> >> If you buy a readily avialable 240V AC Invertor and invert the DC up
>> >> to 240V , then you can simply use normal 240V rated cable to carry the
>> >> power to your house.
>> >
>> >Operating an inverter at the top of a mountain may not be a great idea.
>>
>>
>> Its not a great idea, but the Windmill will still need a charge
>> controller located where the windmill is , as the charge controller
>> also acts as a speed preventer to stop the windmill from destroying
>> itself in high winds.
>
>I thought modern 'windmills' avoided overspeeding using other methods. Applying
>a high load can also break things.
>
>
>> Unless the OP buys one of the top end Windmills that have self
>> feathering blades, and if thats the case, the cost of the wire becomes
>> irrelavnt.
>
>I agree that the precise choice of windmill is very important in such an
>application especially.
>
>Graham
>
>

Most of the cheaper Windmills have a dummy load in the Charge
Controller which dumps power when the windmill spins too fast.
The incoming frequency on the AC side is measured.
If the Charge Controller can dump the power into the batteries it will
but you have to guard against hi winds and a fully charged battery as
that is the worst case.
Even so, they still have a max rated wind speed.

The Air X Turbines which are fairly common but not cheap have
carbon Fibre blades which are designed to self feather so that they
self limit the speed in strong winds.