Build Your Own Savonius VAWT (Vertical Axis Wind Turbine)

141,738

109

30

Posted in WorkshopEnergy

Introduction: Build Your Own Savonius VAWT (Vertical Axis Wind Turbine)

Build a cheap VAWT from a broomstick, 4 bearings, 2 buckets and some pipe.

Step 1: Get Some 25mm ID / 50mm OD Bearings

Go get at least 2, or ideally 4 ball bearings with a 25mm (1inch) inner diameter, and a 50mm (2 inch) outer diameter. I bought mine for aout 6 Australian Dollars each at my local bearings store.

Prise the side seals off and scoop out all the grease, then rinse the bearings out with some diesel or turpentine to make them spin easier, then pop the seals back in. They should spin easily now.

Head down to the hardware store and find a cheap broomstick handle that just fits inside the bearings. Dont worry if its a tight fit.

While you're at the store buy some 50mm (inner diameter) PVC tube and 2 large buckets (I found about 20 litres ideal).Also uy some long screws - I used plaster screws at least 50mm long.

Step 2: Make the Shaft

Cut the PVC tube to be slightly shorter than the room handle, and then cut if in half again.

Tap 2 bearings to be close to the center of the broom handle, then slide the 2 lengths of the PVC tube and tap it down so its a nice tight fit, then tap another bearing into each open end of the tube.

I also fitted an end cap to one of the tube ends, as well as a bell shaped fitting to keep the rain out (see picture). Screw the top piece to the broom handle in the center so its fixed to the broom handle. The broom handle has now become the center drive shaft.

Check out the video - you now have a free spinning drive shaft - I have a small piece of dowel I drilled into the bottom of the broom shaft to show rotation while clamped in the vise.

Step 3: Add the VAWT Blades

Cut both buckets in half so you have 4 blades. It pays to have the dog check your work ;)

I used an electric saw and just held it there while gravity did all the work. You could use a handsaw easily.

Then use a holesaw to make a hole in the top of each half, so it will fit over the top of the broom handle sticking out of the top of the shaft.

Please be careful and take the time out to think at each stage - the author accepts no responsibility for sloppy planning!

Step 4: Add a Blade

Screw on half to the top of the shaft.

Add some screws down the side - by using thread on the screw you can the leave a gap between the blade and shaft as it increases efficiency.

Step 5: Add Another Blade

Add another blade

Step 6: Add the Other Two Blades

Add the other 2 blades below, at 90 degrees to the first two. This gives a much smoother running, and a better chance of the blades facing the wind at startup.

Remember to cut 50mm holes in the top of each bucket half so they fit onto the center shaft.

You can drill small holes where the top 2 blades meet the bottom two, and tie the blade sets together with wire or cable ties. This really stiffens the whole strucure up nicely.

Step 7: Trial Run

You now have a nice lightweight turbine to bolt to something heavy. Unfortunately I had little wind for one of the videos - the unit goes great above 10 kilometers per hour but this short gust is the best I could get yesterday.

You can see from the little coloured toy windvane that even though there's no wind, it starts in the lightest of breezes. It has a truckload of torque too when the wind is aout 20 kilometers per hour.

In the second video I have added two large blades from large domestic garbage bins. I tried grasping the broom handle and stopping the centre shaft coming out the bottom - too much torque! Tonight I'll add the other two blades. With a much larger blade radius I should be able to pull a lot more watts off of it!

Step 8: Time to Make Some Power

I'll add a generator set soon. There's plenty on my workbench.

With the following assumptions:
m(air) = 1.2 kilos per cubic meter
area(frontal) = 0.7 square meters
windspeed = 5 meters per second (about 15 kph)

Then Watts = 0.5 x 1.2 x 0.7 x (53)
= 52.5 watts

However Savonius Vawts seldom do better than 30%, so I better find about a 20 to 50 watt DC motor somewhere to try it out.

Check back soon...

Share

    Recommendations

    • Microcontroller Contest

      Microcontroller Contest
    • Science of Cooking

      Science of Cooking
    • Pocket-Sized Contest

      Pocket-Sized Contest
    user

    We have a be nice policy.
    Please be positive and constructive.

    Tips

    Questions

    30 Comments

    Can you make power with your wind turbine?

    yes, it will greatly shorten the lifespan of the bearings and the removal of the seal will allow alot of dust and grime to get in. i would recomend keeping the grease in there, any additional friction caused by the grease will be small and easily overcome by the wind

    I would like to use such an equipment to pump water from the lake to a garden near by. Any person with good design on how to go about this

    2 replies

    http://en.wikipedia.org/wiki/File:Waterladder_pump.JPG

    Yes. Search "savonius pump" on Google.

    hi, can the equipment be used to pump water from a 10ft well?

    any update or news? I'm curious how much power you are getting out of just one of these. What will you be powering?

    1 reply

    Hey there, I am now just moved my workshop to a 5m by 9m shed. Expect an update soon! I am going to build a little genset of about 10 watts. But you can check out my other vids on youtube - I have been playing with adaptive blades.
    http://www.youtube.com/user/samdekok72

    does the bottom piece screw down to the broom too? also when you screw the blades on top those screws are short that way they don't touch the bearing? when you screw the blades on the side it doesn't go all way there?

    how long does the screws has to be for the side....

    1 reply

    75mm (three inches) is a good size. take care.

    Good luck on the generator.PM me if you have any Qs about the generator.I have have designed a few wind mills using the higth power WindBlue alternators and have 2 DIY ones from scratch and am now currently working on a micro hydro power project. I'll Even design a template if you want!!But, any requests, please after 19th August!!(will be busy until then)Also I added your 'ible to Green DIY, my group.

    those gaps between the boards in your workbench must drive you crazy!

    1 reply

    Really handy for punching out nails and holding stuff. At first I thought so too - but like most ikea things you just gotta work em out. Cheers!

    I thought the whole point of the overlap between the two halves was that air would flow from one cup to the other. With that pvc pipe in the middle, you can't get any air flow.

    1 reply

    Hmm, not easy to see from the photos I'll admit - but there IS about a 50mm standoff on each due to not screwing the screws all the way in. Study the photos and read the text and you'll get it. You can make the gaps as large or small as you want by adjusting how far you plunge the screws in to the central mast. Let me know if its still confusing and I'll email you photos. SD

    I gotta Try this>>> did you ever settle on a generator???

    1 reply

    I think i'm gonna direct drive a invention i've made for tumble drying clothes outside, rather than take electricity from it.

    But if you went a little larger with the blades you'd easily drive one of these:
    http://www.thebackshed.com/Windmill/WhatFP.asp
    (LG nowsell an equivalent and the brand new spare is only 90 dollars australian!). Lots of other info on google:"Smartdive alternator" search.

    Would love a pic if you build one!

    Just wondering- what do you think about using motorcycle headset roller bearings for the lower bearings? They have cylindrical rollers instead of balls, and should act as a thrust bearing. They're tough, and weather-resistant. They can be a bit expensive compared to standard bearings, though.