Owing to an increasing shift from non-renewable fossil fuels to eco-friendly renewable sources of energy, wind power is gaining immense popularity as an alternative source of energy. Wind power is a clean and pollution-free fuel source, that is renewable in nature. The wind energy is harnessed and used to generate electricity with the help of wind turbines and wind mills. Hence, knowledge about the construction and functioning of wind turbines is crucial, especially at the school level.
Wind Turbine Blades
In order to build a horizontal axis wind turbine, cut out the 24" long 8" diameter PVC pipe into 4 equal longitudinal sections (cut the pipe into 2 halves lengthwise first, followed by another cut lengthwise on both the halves to obtain 4 equal sections).
Take two of these sections and cut them diagonally, from one end to the other, leaving a gap of 30 mm from the tips on both sides. So, you have 4 triangular blades ready, out of which you will need only 3 to make your horizontal axis wind turbine. One end of the blade is broad while the other end is narrow.
Mark one set of holes in all the 3 blades using a marker pen 3/8" away from the straight end and 1/2" away from the wide end. Mark the second set of holes in all the 3 blades at a distance of 3/8” from the straight edge and 1 ¼” from the bottom of wide end of the blades. Drill holes on these points using a driller.
Drilling and Tapping Holes in Hub
Hold the end of the shaft which passes through the hub of the 260 VDC 5 Amp continuous duty motor firmly with pliers and turn the hub clockwise.
Use a compass and protractor and make a template of the hub on a piece of paper. Mark 3 holes, each of which is 2 3/8” from the center of the circle, and equidistant from each other. Place this template over the hub and punch a starter hole through the paper on the hub at each hole.
Drill holes with the 7/32” drill bit and tap the holes with the ¼” x 20 tap.
Bolt the blades onto the hub with the help of ¼” bolts or screws. Adjust the blades so that they are equidistant. Mark and then punch each hole on the hub through the empty hole in each blade. Label the blades and hub using a marker pen so that you can match the spot on the hub with the blade.
Assembling the Turbine Unit
- Sanding the blades will increase the efficiency of the blades and will also make them quieter.
- Any sharp corners of the blades should be rounded off to cut down the noise.
Safety is of primary importance when working with electricity, and therefore be very careful while soldering.
Mount the entire fan assembly onto the base tower.
Thread the wires from the motor through the vertical PVC pipe.
Solder the leads from the motor to a bulb assembly. As the output from this type of turbine is very low, use a red LED bulb as it requires minimum voltage to light up.
- detail windturbine image by Dev from Fotolia.com