windmill

[dhiyanez]

How to make a windmill for our home usages? Tell me some ideas to make more effect wind mill.

 

[giftiger_wunsch]

A windmill? Just to be clear are you talking about a wind turbine, or an actual windmill? My guess would be the former since the latter isn't exactly in the domain of electronics.

The basic principle of creating a wind turbine is to use the force of air flow (i.e. wind) to turn the turbine... a turbine uses permanent magnets and movement to induce a current in a coil. I am personally planning to try to use a 24V DC Motor as a wind turbine by attaching some suitable blades; a motor with permanent magnets can usually act as a turbine.

Mechanically, you'll need need lightweight blades with a high surface area to catch the wind and drive the turbine. You'll need them to be large enough that the force of the wind can overcome the torque of the turbine, otherwise you'll need suitable gears to step-down the rotation, translating rapidly-turning blades with little torque, into a slowly rotating turbine with sufficient torque to actually turn the turbine. If it helps, when I get around to making myself a wind turbine I will probably use thin but relatively rigid plastic with a wide surface facing outwards, which the wind will catch.

Electronically, you could use a bridge rectifier to produce DC regardless of wind direction. If this is going to be a large turbine, I believe you'll need some way of dumping excess power when the circuit is open or not fully loaded, to prevent overheating and other problems. I believe other similar threads have mentioned using a lightbulb to safely dissipate the excess power, I'm sure another member can advise you on this.

 

[BrownOut]

Make the head swivel and mount a big, flat tail so the blades always face the wind.

 

[giftiger_wunsch]

Hmm that could work but it'd have to be carefully positioned or the wind may just blow it around on its swivel base rather than rotating the blades.

Another idea is to create a wind tunnel and put the turbine inside. But depending on the size of the blades that may not be practical.

 

[BrownOut]

That's what the big tail is for.

 

[giftiger_wunsch]

The big tail would have to be carefully designed and positioned to avoid that happening.

It may not be worth the extra effort involved; there is usually a prevailing wind so as long as you orient the device properly, it should catch the wind most of the time without requiring the ability to swivel. Then the additional dimension of rotation means that either sliding contacts will be necessary, or there's a worry of the cables being tangled up as the device swivels.

 

[BrownOut]

Not really. There are thousands of these all across the western US.

 

[giftiger_wunsch]

Sorry I don't know which part that comment was in response to. If you're referring to the tail needing careful design, I'd imagine you'll find that the original design for those thousands of similar devices across the western US involved a little bit more than simply slapping a tail onto it and giving it a swivel base. It requires fairly careful consideration and a bit of tinkering to discover what shape and position it should have to orient it correctly with the wind all the time, and not waste energy by having it blow around its base rather than rotating the blades.

 

[BrownOut]

The shape is flat, and the position is pointing away from the wind. Not rocket science.

 

[PatM]

Do you have some way to stop "Run Away" conditions.
See what can happen:
Windmill out of control - Snotr

PatM

 

[BrownOut]

Wow! I think there are pretty good ways to prevent run away conditions. Variable vane is, I think probably the best way. For a simple home gererator, you might just want to mount the system on a telescoping pole, so that it may be retracted in a storm.

 

[giftiger_wunsch]

The shape is flat, and the position is pointing away from the wind. Not rocket science.

<- skeptical

 

[mneary]

<- skeptical

**broken link removed** for a good photo of a partially assembled windmill. It shows the vane quite nicely. It may require a lot of science to design, but to me it just looks like a big flat piece of metal that's bigger than the wheel that it steers.

 

[BrownOut]

It takes about as much science to design as it took to tie a tail on you kite to stabilize it with you were a kid.

 

[giftiger_wunsch]

I never used a kite when I was a kid.

 

[ronsimpson]

Windmills can be pretty simple. Blades added to a bicycle wheel and a tail fin.
Blade construction varies depending on average wind speed and RPM needed.
100 years ago, dumb farmers, made windmills with tail fins that headed the blades into the wind. At high wind speeds the fin turned the blades away from the wind slightly to slow the speed. At very high wind speeds the blades turned 90 degrees to save the windmill.

 

[giftiger_wunsch]

This sticky gives some pretty useful information about wind turbines.