A vertical axis turbine is set so that the rotor shaft is arranged vertically, meaning that the turbine does not need to be pointed into the wind and the generator, if desired, can be placed near the ground. Building a vertical wind turbine is a great way to use renewable resources to power small home appliances. In addition, a do-it-yourself (DIY) wind turbine will possibly reduce your electricity bill and teach your kids principles of engineering and sustainable living.
When building a wind turbine, keep in mind that actual savings from residential wind turbines, when the costs of materials are factored in and compared to electricity bill savings, tend to be very low, a large part of why only about 1 per cent of world energy comes from wind power. Therefore, have reasonable expectations of your wind turbine and take them into account when planning your turbine specifications.
Determine how much voltage current you would like your wind turbine to produce. Based on this voltage, obtain a motor that promises to produce even more voltage, for relatively low revolutions per minute (RPM). Motors, used as generators, will not produce the entirety of the voltage that they purport to produce at a given RPM, so make sure that your motor is able to produce more than the voltage that you need.
Design your blades based on your motor RPM. Your blades' requisite tip-to-speed ratio, which describes the ratio of blade tip speed to wind speed, depends entirely on the RPM that your motor requires to be productive. Avoid an excessive blade RPM, since this will cause blades to "run away" from the motor, dispelling excess energy in the form of heat and causing damage to your motor. Conversely, an insufficient blade RPM will result in your blades being unproductive.
High motor RPMs require a tip speed ratio (TSR) of between five and seven; lower motor RPMs require a TSR between one and four. Use your TSR to determine what the angles and contours of your blades should be. Purchase the correct blades, or use a band saw and plane to fashion your own customised blades from wood.
Connect your blades to your rotor. Either follow manufacturer's specifications, if you purchased your blades, or drill holes through your blades and use bolts to attach them to your rotor. Connect your rotor to your motor.
Thread an axle through the rotor. Use a locknut and washer to hold the blades, rotor and motor in place at the end of the axle.
Build a plywood frame for the turbine. Use nails to connect three rectangular and sturdy pieces of plywood, large enough to house your turbine. Place the axle that you threaded in the step above on top of the plywood frame, so that your blades and rotor are flush with the plywood frame. Use several wood screws through the holes that are already in the rotor to securely fasten the rotor to the plywood frame. Orient the plywood frame so that the generator blades are facing in their intended direction.
Build a mounting apparatus that keeps your turbine 4 to 5 feet off the ground, both to keep it clear of snow drifts and to get better wind. Nail the unit to a heavy base, such as a 4-by-4 beam. Alternatively, screw the bottom of the unit to a flange connected to a 1-inch black pipe driven into the ground. Both sturdiness and height are critical to your turbine's ability to reach its maximum speed.
Wire the motor generator. First, connect it to a blocking diode, using 12-gauge AWG cable. The blocking diode ensures that charge in the circuit that you are wiring flows only in one direction, from the generator to the battery bank.
Use 12-gauge AWG cable to connect the blocking diode to a charge controller, the next element in the circuit, which allows you to turn current flow between the diode and batteries on and off at will.
Connect the charge controller to your battery bank, with 12-gauge AWG cable. Wire the batteries in the battery bank together using 8-gauge AWG cable. Connect the positive terminal of each battery to the negative terminal of the battery next to it, until only two terminals, on different batteries, do not have wire attached to them.
Use 12-gauge AWG cable to connect the remaining two terminals to an AC power inverter. The power inverter enables you to power your household appliances with your wind turbine.
This is a DIY project that assumes a certain level of construction and electronics experience. Consult an experienced electrician before beginning. Improperly wired electronic circuits and/or generator frames that are not sturdy can cause harm and/or death.