playing at wind power

[sinclairbrett]

Hi i live in the uk in a typical town south of london and tinker at wind power - solar.

I have built some realy simple windmills but only ever manage around 200-300mA from stepper motors even when more than one is connected up and buy using lo volt drop diodes. all the windmills are direct drive simple construction.

What i am realy after is around the 1A at 12V mark

Any ideas

[johnlm]

At about what wind speed are you wanting the 12V @1 Amp?

John

[stevesteve]

Hi, I'm in a similar situation just north of London. A big turbine like some of the guys have in the States (or Scotland) just is not practical. I have just posted some photos of a rotor that I made this evening out of stuff from the local tip. I am going to make a small axial alternator (a bit like the ones on Dan's Monday posts but say half scale or slightly less. I am going to wind coils for 12V but just accept that the current will be lower than their multi-kilowatt monsters!  

[sinclairbrett]

Thats a good question i supose fairly lo wind speeds is the only answer i can give, i rewound one of those old telephone generators to give me 12 v at 500ma but can only just turn the damm thing by hand, i recon my windmill only rotates around 150 200 rpm. But my mates scoff when i tell them my windmill only does 200-250ma when charging 12 v batterys.

Also the windmill does get trouble from local trees thats a prob i guess living in a average street.

Have tried making blades from drain pipe , balsa, and now thin ply no real aero dynamic shape as my profession is communications not wood working

regards

mark

[ghurd]

Maybe try a stepper motor?

Some guys are getting 1/2 amp with a 20" (51 cm?) fan blade.

Low ohm coils (under 10) and voltage about 8 to 12V may be good?

It takes some hunting to find one.

G-

[sinclairbrett]

thats what i am currently using in the windmill ( pic to follow) 2 steppers on the same drive shaft 4 bridge rectifiers all low volt drop gives nearly 30 volts off load the steppers have a shaft that goes right through making connecting together easy all the big steppers on ebay allways go for silly prices

[ghurd]

Could try a very small AC conversion.

Mine gets around 750ma in a good wind.

I am sure it will go much higher after a rewind,

far too much tiny wire in it now.

Just a 20" fan blade and the motor is about 3.5 X 4" long.

Seperated the start and run, added 4 neos. Thats it.

Coils should be seperated more but the wire is just to

fine to figure it out.

Pretty sure it has past the 1A mark,

but didn't have a meter on it.

G-