AL_n wrote:
The Natural Philosopher wrote in
:

I stumbled accross what appears to be a 3-blade microlite aircraft
propellor, and have ideas of using this in the construction of a
small wind turbine for charging a 12v battery. I'm looking for a
suitable motor to use as the generator/dynamo. From what I've
gleaned, I gather a 240v DC motor would be most suitable.

why?

you want a simple motor with lots of winds on it.

All the bits you need are probably available from the electric model
aircraft community.

BUT until we know what windspeed, prop diameter/pitch etc etc its hard
to settle on what exactly is needed.




Average wind speed where I am is about 11 knots, and often reaches 30
knots. Each blade of my 3-blade aircraft propeller is 30" long.

Al


Right. So you might be able to pull a bhp or so out of that lot.

I'd start with a 3 phase outrunner motor then, which with a 3 phase
bridge might be pushing out up to 20-30V at a quite a few amps.

http://www.giantcod.co.uk/epower-bl5...-p-402690.html

for example.

At 2000 RPM that might deliver 10-12v

And a few tens of amps.

How you arrange to switch that into usable charging current for a
battery, is another matter.


Id tend to use something like this

http://www.dimensionengineering.com/AnyVolt3.htm

set to about 14v with a bit of a current limiting resistors in it for
SERIOUSLY flat batteries.


Of course, this os not cheap nor cobbled together from arbitrary scrap
parts. But then, neither is a nuclear power station ;-)