Jeff's Blog

My daily (well I am trying to update daily now) weblog covering topics such as wind power, embedded electronics, software development, CNC Machines and some fun stuff like travel and sailing.

Monday, May 19, 2008

VAWT Video Part 2 - Power Generation.

VAWT Part 2 -- Gears and Generator

Please check out the following link to a YouTube Video of part two of our wind turbine build. Video - Part 2 This shows our geared generator design and a desktop CNC machine cutting gears.

Two other designs are being worked on for future:

1. Geared design shown in this video.

2. A version with a built in rotating cylinder of permanent magnets exciting a stationary coil (permanent magnet alternator) with no mechanical gearing and hence no mechanical loss as is inherent with gears.

3. Another type with a geared automotive generator (no magnets at all) whose mechanical resistance is controlled with PWM(Pulse Width Modulation) by a microcontroller controlling power into the rotating coil. With no power, the coil should free-wheel with minimal resistance. In strong winds, we could "make hay while the sun shines" by putting a lot of juice into the coil. In light winds, the power in the coils is reduced to an amount which still will at least hopefully trickle charge the battery. A small permanent magnet motor-generator would be used to jump start the process and handle the case of a totally dead battery, and could "trickle charge" a dead battery. This design is very interesting from a software point of view, but has the highest amount of technical risk.

The wind speed, RPM, and outputs will be monitored, and more importantly compared, with a flexible sensing and visual programming environment called NeatTools, which will be discussed and "filmed" in future posts. We will also be using a TNG-3B from in conjunction with NeatTools to simultaneously monitor multiple inputs from hall effect sensors (from a small magnet on each turbine axle), voltage sensors, and a wind speed sensor.


Blogger kelbs said...

Hi Jeff, great rotor. I have some ideas for you.

1) Dont use gears, losses aside, if you have 50 teeth meshing at 1 rpm, you'll get a 50Hz noise that is hard to clean up. Consider belt drives if you have to alter speed.

2) Consider mounting a small DC motor inside the center shaft, and then just lock its output shaft to force the rotation. email me if this doesnt make sense.

3) Best option would be to use a Fisher and Paykel or LG washing machine rotor such as shown here->
Scroll to the bottom

You can buy them bew direct from LG as a spare part and you'll kick out the watts at low speed then.

samdekok AT

June 17, 2008 7:50 AM  
Blogger Bob Thomas said...

Great videos and blog about the generator. I haven't studied these problems very long but I have often wondered why people don't use the shaft horsepower from the wind mill to compress air and then use an air powered wrench to power a generator or alternator when needed.

On another note have you seen Maple Ridge up by Lowville, NY? There's quite a wind farm there by northeastern US standards.

August 11, 2008 10:58 PM  
Blogger embeddedprogrammer said...


Good point about air compression. Someone in Europe is also producing a small car that runs on compressed air. I will head up to Lowville (haven't been there in years).


August 12, 2008 1:29 PM  
Blogger Jason said...

I want to first say, that you approach was very intelligent, and I love what you have done. I would like to build an array of these to charge batteries. I wonder what four of five columns would produce, and would there be a way to couple the power produced? Are you documenting the process? Also are you going to sell the gears? I would buy some. Are you going to write up a parts list for lowes or home depot? I think this would be a great power source for third world countries. Also here is the next project I would love to see you work on....;-) small scale of course.
Also what is your e-mail address? I am a web developer, and I would love to help you, and build a site documenting all of this, showing data, and what not.
You are da man

August 16, 2008 7:18 AM  
Blogger davers said...

Research at Sandia Laboratories, suggests an overlap of 10 to 15% of the bucket diameter. Looks like you're using an overlap of 50%. I'd expect a very large power boost by decreasing that overlap to somewhere between 10% and 15%.

November 27, 2008 3:58 PM  
Blogger Nathanael Matthias Weiss said...

jeff.. much impressed at your building of a savonius wind generator.. i want to do the same thing on my sailboat. thanks for the tips.

December 8, 2008 4:52 PM  
Blogger Lance Jungmeyer said...

Very cool ideas Jeff. I posted your videos to my blog at

Really looking forward to part III.

February 8, 2009 11:17 AM  
Blogger dmartin925 said...

I seen in your video you get up past 12Volts, how many Amps are you getting? Basically I'm wondering total wattage.

February 10, 2009 5:00 AM  
Blogger embeddedprogrammer said...

I am getting about 5-7 amps or around 60 watts. That will change when I change the gearing which I am working on now.

February 10, 2009 11:37 AM  
Blogger dmartin925 said...

Changing the gearing how? Ratio? Switching to belt/chain driven setup?

Also, what kind of Alternator is that? Is it a one wire (self exciting regulator) standard 12V car alternator?

February 12, 2009 4:29 AM  
Blogger pete said...

Jeff, I just happened accross your You-Tube demo and it looks very intresting. As an amature to this computing mallarcy,I checked out your Blogg and couldnt help notice your name. Its very simaliar to mine and then Isaw your photo, its also very simaliar to me. I havent yet loaded my photo on to my facebook profile yet.Pete Breslin

January 12, 2010 3:44 PM  

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