You might be confused over the many terms you hear these days relating to wind generators. Allow me to shed some light on some terms and what they mean.
A wind turbine is essentially the same as a wind generator in that it is a machine that captures the force of the wind (a form of kinetic energy) and transforms it into electricity. On the other hand, when a machine transforms electricity into kinetic energy, it is called a motor. Thus, a motor can be used as a generator because energy can be freely transformed from kinetic energy to electricity and vice versa. A rotor is the blade and hub or a wind generator. It is attached to the motor and provides the kinetic energy when it is spun by the wind.
Thus to build a home wind turbine, all that is required is to construct the rotor, attach it to a motor, mount it high enough to catch the wind and transmit the electricity produced into a battery bank for storage and later use. Fortunately, there are many DIY guides in the market that teaches how to do that. By following any of these guides, you can build your own home wind turbine for as little as $200.
If you want to make your own wind turbine, you need to know whether your area is windy enough. You generally need an average wind speed of at least 10 mph in order to make having a wind turbine worthwhile. To find out the average wind speed in your area, look up a wind map. If you live in the US, you can visit http://www.windpoweringamerica.gov/wind_maps.asp and look up your area’s average wind speed.
Here are the basic steps to take to build a home wind turbine:
Make 3 blades out of a PVC pipe. Use a 4” to 6” diameter PVC pipe and cut your blades between 3’ to 4’ long. It is not advisable to make your blades longer than 4’ because it may bend under strong wind conditions. Cut your blades into the shape of a wing and use a sander to give it an aerodynamic curve along the edges. Check that the blades are exactly alike. Finally paint them with UV resistant paint.
If you choose not to make your own blades, you could buy ready-made ones. A recommended brand of blades is Windmax. They are made of fiberglass and are among the best in the industry. They have a low start up speed of about 5.4 mph (this means it starts to generate electricity when it hits 5.4 mph), a high power coefficient (cP) of 0.49 (which means it converts 49% of the wind power into electricity; PVC’s cP is not more than 0.25) and tip speed ratio (TSR) of 8 (it means the speed of the blades is 80% that of the wind; the higher the TSR the more electricity it produces). These are very impressive specifications.
Next screw the blades onto a hub, which is any piece of flat circular metal at equal angles apart. This combination of blades and hub is called the rotor. Make sure you balance your rotor. To do so, make a hole in the exact center of the hub using a lathe. Mount it onto a horizontal stationary shaft and give it a spin. If one blade consistently ends up at the bottom, it is heavier than the others and needs to be sanded down.
The next step is to attach your rotor to the motor. Since the motor is the most important part of your generator, it is recommended you buy a good one. A recommended brand is Ametek. The size of your motor goes according to the length of your blades. Ametek motors have their own hubs so you don’t have to make your own.
Now you need to make a body for your motor so that it is protected from the rain. A PVC pipe or chimney piping will do fine. Cut a line down the pipe and slide your pipe over the motor. Use silicone to seal any cracks or seems that may allow water to drip in. And paint your body with weather proof paint also. The other thing you need for your body is to attach a tail to it so that it will turn towards the direction of the wind. A tail is simply a flat piece of metal (aluminum or stainless steel) joined to a rod and attached to the body. Your body needs to be able to rotate freely so screw a flange at the bottom so that it can be attached to some bearings later.
Now you need to connect your wind turbine to a battery body to store the electricity produced. Using wires will cause them to twist each time the wind turbine swings in a different direction. So you need an electrical rotary connector. Your battery can be connected to an inverter that will change DC to AC current so that it can power your appliances.
Once you have the blades and hub attached to the motor, you need to mount it on top of a tower so that your generator is at least 15’ higher than any object within a 300’ radius. An easy way to get a tower is to use an old TV tower or a tilt-up tower. A tilt-up tower is a tower that has a hinge at the base and is straightened up using a gin pole and winch or vehicle. The advantage of using a tilt-up tower is that you do not have to climb to get to your wind turbine when it needs servicing. It can be done on the ground. Be sure that your wind turbine can rotate 360° at the top of the tower.
You will also need to earth your tower in case of lightning. In all likelihood your tower is made of metal. Earth your tower by tying a heavy-duty gauge wire to the tower and connecting the other end to a steel rod stuck into the ground. This should prevent the lightning from reaching your house. But to be safe, you should use a fuse and a lightning arrestor to your battery body and inverter so that if some of the lightning travels towards your batteries, the fuse and lightning arrestor will blow up and break the circuit thus saving your batteries and inverter.
Most of the components and accessories above can be bought from your local hardware shop or places like eBay. So, making a wind turbine is not too difficult.