Windmill made from washing machine, 555 chip

windmill

Green hacks implement one of two philosophies. The first is über-technical, with very expensive, high-quality components. The other side of this coin creates green power out of junk. [Timot] obviously took the latter choice, building a windmill out of an old washing machine motor and a few bits of PVC.

The generator for the windmill is based on a Fisher and Paykel direct drive usually found in clothes washing machines, rewired to provide 12 Volts at low RPM. At high speeds, the generator can produce 80 Volts, so a charge controller – even one based on a 555 chip – was an excellent addition.

For the other miscellaneous mechanical parts of the build, [Timot] cut the blades of the windmill out of 200 mm PVC pipe and sanded them down a bit for a better aerodynamic profile. With a custom fiberglass spinner, [Timot] whipped up a very attractive power station that is able to provide about 20 watts in normal conditions and 600 watts when it’s very windy. Not enough to power a house by any means, but more than enough to charge a cellphone or run a laptop for a few hours out in the back country.

Comments

  1. AS says:

    Really need to be careful with PVC blades as unblance can make them flex enough to break off at the base and fly qute a ways.

    • SavannahLion says:

      I’m not an expert on the subject but I imagine this is true of any windmill. Youtube has a nice selection of “Windmill Explodes” or “Windmill Exploding” to watch.

      Besides that, what are your options really? Nearly any material I can think of that’s been used in constructing blades are going to be deadly at a high enough velocity if they snap off. Short of constructing them out of NERF baseball bats, it’s a risk you have to assess then take. :\

      • fartface says:

        You add safety cables from the mount bolt to near the center of the blade. the blade will stay attached and simply self destruct the rest of the windmill and it all will slow down. It is easy to make them safer.

      • Dax says:

        >”Besides that, what are your options really?”

        Wood and artifical composites like fiberglass. They don’t just fracture like PVC does.

    • Paul says:

      What about a set of masts with adjustable sails as the blade? you could use a centrifuge clutch to retract them as needed to get the peak use of the wind while guarding against over spin.

      • Paul says:

        Thinking about a while I think i got a better idea set the blades up with variable pitch like a helicopter blade then they could adjust to shallower pitch to slow or even neutral ” flat” to stop rotation which would make servicing them easier and safer.

    • Mike says:

      A vertical turbine design prevents dangerous speeds.

  2. Chad says:

    Most wind turbines have some sort of overspeed protection to prevent it from flying apart. Besides having to balance the blades properly, they will typically have a tail that will point them out of the wind when the wind is too high, or they have a dump load that will put a large resistor on the turbine so that it can’t run too fast.

    In low wind areas, you typically get more wind in winter than in summer. This isn’t always true, but in winter, I would think it better to dump all of your power into an electric heater. You can bypass the inefficiencies of the inverter, charger, batteries, etc, and get whatever heat is available basically for free. …but that’s just me.

  3. Clinton says:

    It’s a neat design, the next revision could use a furling mechanism to protect itself in high winds, to avoid self destruction.

    It’s difficult to tell how his dump function works, and whether there’s any ability to put a braking load on it. Even so, the PVC blades may not handle the stress of facing a high wind, when the turbine is fully braked, and even then it may self destruct.

    Overall though, it’s a neat design, and a good way to repurpose parts at hand!

  4. Chris C. says:

    Nice windmill. Nice video too, a pleasure watching it (unlike some others I could mention).

    For a one-off DIY project, I wonder if the trouble/cost to make it safer would exceed, on average, the trouble/cost that could be avoided by failures; keeping in mind that 100% safety cannot be achieved under all circumstances.

  5. Kaaaaang says:

    The big windturbines usually have a pitch system on the blades to avoid high winds. But I don’t know how to apply a pitch system to a small turbine.

  6. Galane says:

    Check out the homebuilt wind turbines at otherpower.com Many of them have been built using part of a front suspension strut from an old Volvo. There’s also an automatic furling system that uses an offset hinged, weighted tail. When the wind blows strong enough, the thing automatically adjusts its angle while still producing full power, unlike blade feathering systems.

  7. x3n0x says:

    This system could be much improved by the use of an actual switching inverter to get the desired voltage, so that even at high speeds, the power would not be wasted. Also, if you built the inverter right, and wired the motor coil for higher voltage, your efficiency would increase, as you would have less I2R losses over the long cable runs needed, and be able to create the 12V at the point of load.

    Also, as mentioned above, some sort of furling setup where the turbine turns away from the wind would be the most effective control system, and if done right, would even serve to regulate the voltage to large degree, making the inverter design easy to create.

    Cool project! Now I need to find a trashed direct drive washing machine somewhere and build one!

    • David says:

      They are a lot easier to find in Australia and New Zealand.

    • Jonathan says:

      What if you put sheer pins in the blades? Attach them on a hinge so they can rotate flat when the pin breaks. Tricky to get the pin to break from centrifugal force and the hinge to rotate horizontally but it’s doable. The blade bracket would slip over a rod that had a cap at one end. The bracket would slide into a slot on the hub and then you insert the pin. As the pin sheers off, The blade is pulled out and hits the stop at the end of the rod. The wind forces it to rotate flat and it will slow down. Might only work if you attach all the blades to one sheer pin. If all the blades don’t break loose at the same time it would tear itself apart anyway.

  8. echodelta says:

    I have seen a couple of these small commercial made wind generators in factory yards. Apart from the tax write off and symbol they’re a joke, outdoor lights are still a blazing in the day while it’s turning. Lotsa lead acid, if no powerlines near-by OK: otherwise.
    PVC and sun bad mix.

  9. AussieTech says:

    Neat hack. The F&P motors are a gift for small windmills like this.

    Two questions to explore for anybody considering a similar build;

    1) why do “real” wind turbines use a *lift* section for the blades?

    2) why do “real” wind turbines have only *three* blades?

    Google “Dunlight” for details of a successful series of homelighting windplants, and blade pitch adjustment mechanisms. Some of these units are still in service in off-grid applications.

    • Roger Wolff says:

      The RPM of the windmil is inversely proportional to the number of blades. So if your generator can handle the lower RPM of 5 blades, there is not much of a problem.

      On the other hand, with the aerodynamic properties of these PVC blades, it just might be the case that 5 blades manage to extract more power from then wind than just two. Similarly the five blades will start turning in a lighter wind because there is 5 of them to overcome the static friction forces….

      • Dax says:

        The tip speed ratio of the windmill affects its efficiency. TSR is how much faster the blade tips travel relative to the wind speed.

        For every type of turbine, there’s an optimal speed ratio where it attains the best efficiency, and for five blades this top efficiency is lower than for three blades, and it happens at a lower ratio than for three blades which means the optimal turbine speed is lower, and the range is narrower which means that the five bladed turbine must be loaded in such ways that the turbine speed follows the windspeed more accurately, which requires more sophisticated control mechanisms to maintain optimal production.

        What this means in practice is that the five bladed turbine saturates really easily because you can’t keep it in the butter zone.

  10. Not a windmill guys, this is a wind turbine. Mills mill things.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Follow

Get every new post delivered to your Inbox.

Join 94,628 other followers