The Clean Energy Blog

Useful & Relevant Info On Renewable Energy

Jul

17

Building a Wind Generator: Mounting the Blade Assembly on the DC Motor

Posted By: Freddy on July 17, 2009 at 12:25 am

Your homemade wind generator must be able to spin freely to face the wind at all times. The horizontal axis that the hub assembly sits on, must interact with the vertical axis of the tower in such a way that they are held secure, but will also spin to meet the wind direction.

You can use a simple bungee cord mounted between the pipe and the body of the generator to keep it from spinning around erratically and twisting up your charging wires. With a bit of plumbing supplies and some ABS (or PVC) pipe we can accomplish this goal quite quickly.

wind turbine assembly

First we will assume that at the top of your tower is a vertical section of pipe. Your entire tower might be steel pipe that you have managed to find. Use at least 2 inch pipe for this purpose.

On top of this pipe, the wind generator assembly must sit, and be able to spin. We usually mount a simple flange assembly on the body of the wind generator for the pipe to fit into. Make sure that the flange holds at least 3 inches of the pipe from the tower, and that it will move easily. We do at times weld a 10 inch piece of pipe onto the flange for strength. It really depends on the wind generator size.

If you are building a wind generator more than 6 feet in blade diameter then add some more strength to the flange for safety.

The body of your homemade wind generator

First off locate a piece of ABS or PVC pipe that the DC motor would fit snugly into. This will depend on the size of the motor, but most will fit inside of a piece of 6 inch pipe quite nicely.

Cut the piece of pipe 2 inches longer than the DC motor. Next, you will fill the blade assembly end with a piece of wood with a hole cut in the centre so that the shaft of the motor can extend out. The shaft has to connect to the blade assembly eventually.

Before you put the DC motor inside this permanent weather shield you will need to attach the 3 inch flange to this piece of pipe. Keep the flange mount as close to the blade assembly as is practical. Consult with the Tilt-up assembly drawing below to make sure you get this part right.

tilting assembly

Remember, the blade assembly is very heavy and you will want to balance the whole affair atop the pipe from the tower. A bit of experimentation will be necessary to achieve balance.

You should be able to find PVC fittings to reduce the 6 inch pipe that houses the DC motor down to a 3 inch pipe for the tail assembly. Attach the two together. A tail length of about 2 to 3 feet is quite adequate.

In our next post we will discuss how to build the tail.

If you want a complete blueprint on how to build a home made wind generator, check this site: Build a Homemade Wind Generator

    Filed Under: Alternative Energy Sources , Wind Power Tagged with , , , , , , , , , , , , , , , , , , , ,
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Jul

06

Building a Home Made Wind Generator: Cutting the Blades

Posted By: Freddy on July 6, 2009 at 12:51 am

This post is the third of a series of posts describing how to build a home made wind generator.

Check the first post on How To Build The Blades

Check the second post on What Materials To Use To Build The Blades

OK, Let’s get into how to cut the blades

Using a 4” to 12” sewer PVC pipe, you will cut it quartering the pipe, and then you will cut out one blade, and use it as a template for cutting out the others. That will leave you with 4 blades (3 plus one spare).We are going to build a 3 blade assembly. You can use a jigsaw to cut the pipe. See the figure below


cutting the blades
Cutting the line with a jigsaw

The first step in cutting out the blades is to mark the pattern on the pipe with a marker. A tape measure and a large piece of project cardboard or Bristol board works great for transferring your pattern.

Notice that the centerline is slightly offset when cutting the first blade. This is to catch the wind more effectively. This first blade will be used as a template for the two other blades. See the figure below.


Cut Offset
Notice that this example design pattern is set for a 10 inch pipe; in this way a 4 feet long blade will be on one side 7” wide and on the other 5”. If you use smaller or larger pipe diameter, just add or subtract one half inch of width for every 2 inches of pipe diameter as in the table below.

Pipe
Diameter
Blade
width at hub
Blade
width at tip
4″ 5.5″ 3.5″
6″ 6″ 4″
8″ 6.5″ 4.5″
10″ 7″ 5″
12″ 7.5″ 5.5″


You can then do a little extra smoothing and shaping using a belt sander, palm sander or just sand paper on the cut edges to try to make them smoother. Smooth the sharp corners at the tip of the blades as well. This will serve to make the air flow better, thereby creating a better airfoil.

Wooden blades

Wood is also a recommended material to make blades and cedar is a nice wood. The Eastern White Cedar and Western Red Cedar have the same characteristics of lightness, super strength, flexibility and superb outdoor weathering capabilities.

For the building of your homemade wind generator blades you will want to find planed, finished lumber as thin as you can, preferably only one inch in thickness.

If you can’t find one inch lumber, ask at the lumber yard if they will cut it down to that size for you. The lumber piece should be 6 inches wide and 4 feet long for a single blade.

Use a jigsaw with a wood blade of fine teeth. Make each blade the same by copying the pattern 3 times.

Just put a small spacer piece on the leading side of each blade to tilt the blade in the direction of the wind. A slight tilt of 10 degrees is fine. Use a small piece of wood or angled metal to achieve the results you want to make that blade spin.

In our next post we will be discussing on how to build de hub that holds the blades together.

If you need a complete blueprint on how to build a home made wind generator CLICK HERE

If not, that´s Ok, just keep on checking our series of posts to get the whole picture to start your own project.

    Filed Under: Alternative Energy Sources , Wind Power Tagged with , , , , , , , , , , , , , , , , , , , , , , , , ,
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