Wind "Gen-1"

Wind Generator (Version 1.oh)...

a "proof-of-concept" project...

This page documents a simply Wind Generator that is a "proof-of-concept" model. It was never intended for extended usage, but more so to determine viability of the model, and to get some basic data as a reference before investing too much effort into a more complete project.

These are just a few of the dozen or so "Box-Fans" that I've encountered over the last few years.

My wife will go through 2 or 3 per year in her dog grooming business... over the last 15 years I've watched the quality of the fans steadily deteriorate.

The materials are significantly more flimsy, and the incidence of motor failure is predictable within 12 to 18 months of daily use.

Typically used fans of this style sell for $5 to $10 at garage sales or free in the landfill.

The heart of the generator is a common stepper motor. The unit pictured above is a bipolar stepper that has a coil impedance of 2 ohms with a rated voltage of 4.1V per the data tag on that back. In theory in would draw 2 Amps of current, but what type of current it can source has yet to be determined. These steppers were purchased from a computer surplus store in Ottawa for $7/ea.

The blade from the box fan is coupled to the stepper with a simple aluminum coupler turned down on the lathe. The fan portion is sized for a snug friction fit, while the stepper end is drilled and tapped to accept 2 set screws.

Bearing in mind that this is just a model, I opted to use a scrap of plywood to mount the stepper and fan blades to.

The assembly is mounted inside the gutted metal frame that the original fan was in.

This bipolar stepper only has 4 wires or 2 coils.

I opted to wire in 2 bridge rectifiers (one per coil) and wired the output of the bridges in series to achieve a higher output voltage.

Using a mechanical tachometer to determine the speed of my drill I found that in "low speed" mode it spun at 350RPM, and in "high-speed" mode 950RPM.

Each Coil measured approx 4VDC when spun at 350 RPM, and 11.3VDC when spun at 950 RPM.

The connection of the bridge rectifier's in series measured approx 21VDC when spun at 950RPM.

The short circuit current measured 450ma...

I believe that the power that this unit can deliver (provided there is enough wind to spin it up to 950RPM) is approx 10watts.

The box/frame is bolted to a steel support with a short length of pipe welded to it.

A 16" length of pipe that will be affixed to a pole will slide into the base of that generator and allow it to swivel.

The experiment is set to begin, but as luck would have it there was no wind for 2 days.

The steel box/frame definitely hinders the fan's ability to catch the wind, and required that the fan be faced directly into the wind before it would start to move.

If this proves workable, than a more durable frame with a "Tail" will be made.

On the 3rd day we had a solid day of wind, notice the leaves on the tree in the background has it's leaves turned-up.

The generator was producing 18VDC and approx 400ma of current.

That was all I needed to see.

The current setup is only 7ft off the ground and between 2 barns. Our farm is located on a hilltop and we do experience a persistent breeze from the west.

This post is approx 16" high and solidly cemented into the ground. It has been hit at about 30kph and completely destroyed the steering tierods on a truck I had in the mid 1990's.

This will act as a support for a cedar pole to gain more height for the production Wind mills.

The Cedar pole has had one side faced flat to mate to the steel post, and a corner faced onto the opposing side to have the steel angle bracket act as a back support.

The idea is to bolt the pole to the post with 1/2" threaded rod.

The next installment hopefully will have this successfully accomplished.

This the "production" wind frame, that will hold the Stepper/generator, offer a mount for the swivel base, and a tail support.

This is a foam pattern that will be cast in aluminum.

It took less than an hour to draft out the simple toolpath that is used to cut the guide lines into the foam.

The CNC mill cuts the complete pattern in about 15 minutes.

These four patterns hopefully will yield at least 2 or 3 usable wind/frames.

The sides and top will be enclosed by either a sheet of tin from a large juice can or the clear plastic from a 2 liter pop bottle.

The idea is to make these units from readily available materials as easily as possible.

I admit that casting the wind/frames may be over-kill and deviate from that objective, but in my case it is the easiest and hopefully will prove more robust than any wood equivalent.

I particularly like the simplicity of this project, and a 10 watt yield is fairly decent considering that Solar is still around 8 to 10 dollars a watt in Canada (retail pricing). I wish I could take credit for coming-up with the idea, but unfortunately it has been floating about on the Web for a few years now.

The claims that I've read vary from 2 to 5 Watts up to I think 30watts from a stepper that looked far better suited to a CNC mill than a generator. Like most things in life, one can read numerous postings about a particular subject, but never truly know that what they've read is fact, fiction or somewhat exaggerated until finally doing it them selves.

This project hopefully will spawn a total of 4 generators totaling 40Watts of power... again I have no illusions that our household will become wholly sufficient on such a small output, but by dabbling in the basics of renewable energy, I hope to eventually develop the skills and expertise to graduate to larger wind systems, with a the long term objective of making a 1KWatt unit in the far future.

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