Sunday, February 24, 2013

Homemade 1 kW wind turbine

The 1000 Watt flux wind turbine was created as part of an off grid power project. This wind turbine uses a permanent magnet alternator to generate 3 phases to charge the battery bank. This wind turbine works spinning 2 magnet discs on both sides of the coils to generate electricity. The act of moving magnets of opposite pols past a copper coil will generate an electrical current. The first step will be to build the magnet disk. Using a piece of wood and a jig saw cut out slots equally spaced around the circle for your magnets, it is important to note when laying out the magnets be sure to adjust the polarity (N, S, N, S, N ... etc) For this turbine we used 24 magnets in total, 12 for each disc.

Home made Wind Turbine

Once you have your template the next step is to lay the magnets in place on top of a smooth surface, use plastic or cardboard to build jacket around the circle of magnets. Note: you will want to build two of these disk, one for each side of the coil. For magnets you need to use either neodymium or rate earth magnets.

Magnets placed into our wooden template

Once this frame is in place remove the wood template place a small cylindrical object the center magnets (a paper cup worked in this case!). Pour fiberglass resin into the mold and let dry. This will create a very solid disk to house our rotating magnets.

Pouring fiberglass resin around our magnets

Now that we have our magnet disks hardening its time to build the coils! When building the coils, its a good idea to use 2 strands of wire per coil. A single strand would produce approximately half the out put giving you a 500 W wind turbine, so fro maximum output double it up! Now you need to create 9 coils using 14 gauge copper wire. The coils are wired in a rectifying diode pattern in order to let the electrons flow one way. The number of turns of wire will depend on your desire output voltage.
Voltage to turn ratio is as follows 12 V – 35 turns, 24 V – 75 turns, 48 V – 144 turns etc.
Using a sheet of wood out a circle the approximate size of your magnet disc, affix the cutout onto another board to giver your self a “mold” to resin in your copper strands. Be sure to place a smaller circle in the center of the mold for your future shaft to go through. Since we have 9 coils we are creating a 3 phase pattern, every third coil (the corresponding matching tape) is wired together in series. Lay the wires in a 2 phase wye pattern, lay on some fiberglass matting and apply fiberglass resin.
The video below is an overview of the wind turbine in this tutorial by Steve Spence. So be sure to check it out, you also get a sneak peak of his recycled off grid home.

Nine dual wire copper coils
Resin your copper coils

Next we need to build the hub for all this to to be mounted to, The hub is created by using two pipes and some Harley Davidson wheel bearings. The smaller pipe is placed inside of the larger pipe secured by the wheel bearings.

Wind turbine bearing assembly


The blades were built out of 2 x 6 pine boards cut at a 10 degree angle and sanded to a smooth air foils finish. This design was created by Steve Spence, for more information on this project be sure to check out http://www.green-trust.org