Wind Turbine
 

 

Savonius Wind Turbine

Soon to have an additional rotor on top, to bring the rotor height up to 5'.  This will increase the overall efficiency of the wind turbine.  The optimal height-to-width ratio is about 7:1.  Currently my design is 1' wide and 2' high with the additional rotor on top it will be 1' wide by 5' high.  This will increase my height-to-width ratio from 2:1 to 5:1.

See the Video of it spinning- 1.5MB MPEG

Rotors

  • 3/8" x 3' All-Thread stainless-steel rod, supported by two greased ball bearings in the base.
  • Each rotor was constructed from 3" aluminum chimney pipe.
  • Fastened to 1" block of wood using angle brackets.
  • The overall dimension of the first rotor is 1' wide and 2' tall.

Base

  • I designed the base to be heavy enough and strong enough to completely support the rotor
    • This eliminates the need for an upper support, which would reduce the overall efficiency.
  • Top and bottom plates were constructed from 1/4" pine laminate and 1"x2" supports.
  • The overall dimensions of the base - 10" high, 1' x 2' base. 
  • The weight of the base is heavy enough to prevent it from tipping in strong winds.

Electronics

  • Coming soon.  Am considering two methods of generating the electricity:
  • Permanent magnet motor connected via pulleys/gears or create the generator myself, using this method.

 

Savonius design basics

There are several variations of Savonius rotor. The efficiency of a Savonius is only around 15 % but they are ideal for many situations. They will start spinning with very little wind, produce a great amount of torque, and need no speed limiter.  The Savonius rotor is designed for low RPM applications, and will never spin faster than the speed of the wind.   Some variations are shown below, looking down from the top of the turbine.

The most basic design. It is very strong due to the central shaft, but slightly less efficient than the other two. It is less efficient, because it does not allow some of the air to be deflected onto the opposing rotor.
This design is also very simple, and can also be made easily from metal drums or pipe sections. The design is slightly more efficient than the one above as some of the air is deflected by the second vane as it exits the first one.
This is the most efficient Savonius design, and was the basis of my design.  It not only has the advantage of air being deflected twice like the design above, but also that the vanes act partly like an airfoil when they are edge-on into the wind, creating a small lift effect and thus enhancing efficiency. This design is much more difficult to build, requiring vanes rolled from metal sheet instead of being cut from drums or pipes.