Sustainability Hacks: Wind Turbine Generator

With a little bit of thought put into the build, a wind turbine generator can be one of the greenest ways to generate electricity. Wind power doesn’t require a semiconductor fab lab (unlike solar panels) and doesn’t have very many environmental consequences (unlike hydro power). The Tech Junkies put up a build log of a wind turbine that ended up being a very easy build.

In the interests of sustainability, The Tech Junkies found an old 1.5 HP DC treadmill motor. After measuring the voltage output when the motor was connected to a lathe, they discovered the power output was very linear. With a little bit of calculations, they realized they needed about 1000 RPM to get 20 Volts out of the motor. The team connected an inverter (it’s always cool seeing a power meter run backwards) and started fabricating the blades.

The team found a wealth of info on blade design on this site and following a few guidelines made six blades out of 8″ diameter PVC pipe. An aluminum hub was fabricated and the whole shebang was put on top of a found steel frame.

The Tech Junkies’ build produces 10 Watts of power but they’re looking to increase that to 500 W with the appropriate gearing. A great build that harkens back to this awesome webpage about turbine building and living off the grid.

18 thoughts on “Sustainability Hacks: Wind Turbine Generator

  1. Too bad wind turbines hardly ever pay themselves off and break all the time.

    Let’s just build some goddamn thorium reactors and fix this huge mess. We have enough thorium in the US to power us for about 3,000 years…

    1. I know a man with a 150kw windmill on his property that he has had since the beginning of the 90’ies. even counting repairs and such, it has paid it self a few times over, an can probably stand 10 years longer, if not more. With todays price on electricity, it earns more a year than many people do with an ordinary job.

    2. When they charge $40,000.00 to connect you to the grid, wind turbines are a very inexpensive alternative for some rural houses.

      Around here, combined wind/solar PV is the way to go. Wind in the winter is abundant and solar is plentiful in the summer. Both provide a portion of the power all year. They compliment each other in a cost-effective manner.

  2. Why would changing the gearing do anything to the wattage? Surely it’d change the voltage/ampage ratio and maybe lose a little wattage with more gears due to loss in heat?

    1. Because the generator is not matched to the turbine. The turbine turns too slowly to get the generator up to a usable voltage.

      Actually they’d do better to remove three of the blades and forget about the torque from low wind speeds. There’s no power in those winds anyway. By going to three blades, the rpm will go up and they can keep the simple (no gears) design.

      1. They’ll get the rotor to turn perhaps a few hundred RPM, and less if they want to increase the size of the rotor because the wingtip speed limits the efficiency of the rotor.

        A better alternative is to wind your own permanent magnet generator rather than use existing motors, because they’re designed to run too fast.

  3. i read this as being a machine that generates wind turbines, and was very impressed for a second.

    as for thorium reactors, that’s great, but i cant build one of those. this is something i could put together myself, which makes it kinda fun.

    1. A generator is simply a motor with the input and output reversed(you put mechanical energy in, get electrical energy out, as opposed to the other way around.) You could build your own with magnets and wire, but it’s much easier and more cost-effective to buy one ready-made, and most motors are more power-efficient than the average tinkerer could build, anyway.

      Try it sometime: take two motors, wire them to each other and nothing else, turn one, and watch what the other one does. I used to have a Lego Mindstorms set, and the motors were efficient enough to not just run the one they were connected to, but light up the LED on a light sensor which was connected as well.

    2. Put simply: yes.

      It would be better to wind up a disc-type generator with strong neodymium magnets, because A) you can mechanically adjust the magnetization by increasing or decreasing the airgap, and B) it’s trivial to wind it for high voltage at low speed.

      The only problem is that you have to source some extremely strong magnets, which kinda counters the argument that you don’t need a semiconductor fab; well, yes, but you do need neodymium.

  4. From my own experience, old floor buffer motors make awsome generators, they’re much cheaper than ‘generators suitable for wind turbine’ crap you see on eBay and need a modest rotational rate to give a respectable output. Usually, you can get a few volts just by spinning them with your fingers. Attach a drill and you’ll easily get 30v out. I typically get 25v in our usual wind conditions here in Spain. Just my tuppence worth….

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