Entrants so far...
Well, I built one entirely out of scrap parts (no cost to me, but to buy the
parts would probably cost less than $30) that completely MELTED two bridge
rectifiers from computer power supplies (5A).
The construction involved cutting a length of 3 inch PVC drain hose into two 2 bladed props, each offset by 90 degrees to make a four bladed prop. Yes, it had vibration issues due to the even numbered blade design, but it worked pretty good once hooked to the generator. I then drilled a 3/8 inch hole for the mounting bolt.
The mounting bolt was held in the chuck of an 18V cordless drill motor/gearbox. This became the generator (permanent magnet DC motor).
I then took some lamp cord, a rectifier out of an old computer power supply, and hooked it up to my Coleman Jumpstart pack (12V battery).
A 15-25 mph wind set it spinning and the LED's on the front of the jumpstart pack showed that power was going into the battery (it was fairly low on power as I had used it several times without recharging it). When the wind gusted up to about 40mph, the generator screamed up and produced enough power that it blew the rectifier (5A). So I figure it was producing AT LEAST 75W (6A). I then scavenged another rectifier from another power supply to try again. Another gust later and this rectifier actually SMOKED, so I figure it had produced about 100-120W (10A).
Gotwind comment Not sure about this one? - If you are using a permanent magnet DC motor, why were you using a 5A rectifier?, surely this is only required with an AC generator, this was probably the cause of 'smoking' the rectifier and not the power you thought you were generating.
This one cost
me about $2 (£1.40 UK pounds)
for the rectifiers.
Around 30W.Its a 3 phase PM motor that I got free from NTL, maybe from a sewing machine?
Cut blades from a 6 gallon laundry detergent pail.
Screwed them on the hub, a hunk of particle board.
Drilled a hole in the hub a tad smaller than the shaft. Beat the hub on.
Added 2 bridges.
Put it on a piece of 2x4", added a piece of panelling and a furing strip, balanced it then drilled a hole there, set it on a 1" copper pipe, that is in a hole drilled in a stump.
and screws came from when I remodelled the kitchen.
NTL bought the motor scrap, maybe $3? So I guess it should count as $5 total.
Ed's microwave windmill cost a lot more, I think he figured $8 (60% more!), but it has nice plans. Looks a lot nicer too.
I'm sure others have $0 in much nicer, more powerful machines.
I've got about$7.00 (4.80 U.K Pounds) in nuts and bolts in these two. All the rest came from dumpster diving (including the test stands).
No power rating indicated !
1. Our main goal is to make renewable energy as affordable as possible - even less expensive than DIY where possible.
2. We will benefit from some free advertising - which reduces our costs in getting the products to market.
Our Wind Generator was designed to be simple and efficient with fast and easy construction. Chispito is a 100 watt machine and can be
built for under $30 USD (12 UK Pounds). utilising a 260 VDC, 5 A continuous duty Treadmill Motor and 24" length PVC Pipe blades.
We do offer Bare-Bones kits on our web site for some of the harder to find parts.
Most of the tools and materials in this manual can be found in your local hardware shop or junk pile. For more
information and inspiration on wind generator construction, please visithttp://www.velacreations.com/chispito.html <
Machine made from scrap steel and wood. Magnets and winding wire donated 700 watts @ 12 volts
Rotor diameter 3.6 metre made from Douglas Fir . 3 phase alternator uses 16 magnets and 48 slot stator, old trailer bearings for the drum and yaw shaft ,fence post for boom with a ply wood tail.
No price indicated!
Peter Cottrell - Australia
Unfortunately I don't have the time to build it myself but hopefully it will inspire other wind generator designers
Samuel Schlatter - New Zealand