In our article Savonius Wind Turbines we looked at this particular type of vertical axis wind turbine generator. In this article we will show you how Sam Dekok in Australia has put together a DIY VAWT using 4 bearings, 2 buckets, a broom handle, and some PVC pipe. With this assembly connected up to a suitable generator, stepper motor, or DC motor will generate electricity from the wind.
Building a Savonius Turbine
A Savonius wind turbine works in much the same way as an anemometer with cups being pushed around at the same speed as the wind which hits them. In this design, the buckets are cut in half length-wise to produce four cups/blades.
Two bearings are then tapped into position at the centre of a length of wooden broom handle, and two further bearings are positioned near the ends of the handle. A piece of standard (47mm) PVC pipe is cut to a couple of inches shorter than the broomstick handle, and then cut in half. Each half is slid over the bearings and handle assembly so that they meet in the centre with one bearing at each end of the each piece of PVC pipe.
If you now hold the exposed end of the broom handle, the PVC pipe can be rotated freely around it thanks to the bearings fitted to it. It is to this PVC shaft that the wind turbine blades are fitted.
Each bucket is cut in half, and a holesaw used to cut out a hole for the broom handle to stick out of at the top of the shaft as pictured above and below.
The blade can then be screwed permanently into place. The second blade is fitted in much the same way as pictured below.
The remaining two blades should be fitted below the first two and rotated by 90 degrees so that the finished turbine will be balanced and rotate smoothly. This also doubles the likelihood that a blade will be facing into the wind. This time holes equal in diameter to the outer dimension of the PVC pipe have to be cut out of the base of each half of the bucket so that they fit over the centre shaft.
Note in the image above how the blades have been tied together to stiffen the whole assembly. All that is the left is to connect the turbine to a suitably matched generator.
Click here to view full details of the Build Your Own Savonius VAWT on the instructables website.