Introduction
Building your own small-scale wind turbine from scrap materials can be a fun and rewarding project. Wind turbines harness the power of the wind to generate electricity. While commercial wind turbines are very large and expensive, small-scale wind turbines can be built at home using common materials and basic tools. In this comprehensive guide, I will walk you through the entire process of designing, building, and installing your own scrap-material wind turbine.
Materials Needed
To build a wind turbine from scratch, you will need to source the following materials:
Blade Materials
- Plywood or lumber for the blade frame
- Corrugated plastic or metal sheets for the blade surface
- Adhesives and fasteners to attach the blades
Generator and Drive Parts
- An electric motor to use as the generator
- Truck or car alternator to generate power
- Bicycle parts like wheels, chains and sprockets
- Fasteners and hardware to connect parts
Tower and Mounting
- Metal pipes or poles for the tower frame
- Guy wires and anchors to secure the turbine
- Bearings to allow the head to turn
- Nuts, bolts and brackets for mounting
Electrical Components
- Inverter to convert AC to DC power
- Batteries to store energy
- Wires and connectors
- Charge controller and dump load
Tools Needed
Basic hand and power tools like wrenches, drills, saws and welding equipment if available.
Blade Design and Construction
The most important parts of a wind turbine are the blades. Well-designed blades capture the wind energy and convert it into rotational motion.
Blade Size and Shape
- The blade length (1 to 5 feet) depends on your materials and wind speed. Longer blades capture more wind.
- Many DIY designs use 3 to 6 blades for simplicity and balance.
- The blade shape should have a broad surface and curved profile like an airplane wing.
Blade Frame
- Cut your chosen material (plywood, lumber) into long strips to make the blade skeleton.
- Use dowels, glue and screws to attach and reinforce the pieces.
- Make a central hole for blade mounting.
Blade Skin
- Cut corrugated plastic or sheet metal into blade-shaped templates.
- Use adhesive and rivets to fasten the skin over the blade frame.
- Seal the edges with silicone or epoxy.
Testing and Balancing
- Check the blade balance using a broom handle. Sand down any heavy spots.
- Test the blades by spinning them slowly. Modify if they wobble or vibrate.
Generator and Drivetrain Assembly
The generator and drivetrain convert the rotational energy from the turbine blades into usable electricity.
Generator
- Use a permanent magnet DC motor as the generator. More voltage is better.
- Connect to the drivetrain using a coupling, pulley or direct shaft mount.
DC to AC Conversion
- Use a power inverter to convert the generator's DC output to AC.
- Match the inverter voltage and amps to your generator.
Drivetrain Considerations
- Use bicycle parts, pulleys and belts for speed control and gearing.
- Allow for misalignment with flexible couplers.
- Reduce friction using ball bearings at pivot points.
Tower Design and Installation
The tower holds the turbine high above obstructions where wind speed is greater.
Tower Height
- 20+ feet is optimal for small turbines. Higher is better.
- Keep the turbine base at least 15 ft above roofs and trees.
Tower Materials
- Use metal pipes, poles, or lattice framework for the tower.
- Galvanized steel resists corrosion. Avoid weaker materials like PVC.
Base Mounting
- Mount to a concrete pad or pier blocks with anchor bolts.
- Use guy wires if needed to stabilize the tower.
Tower Access
- Include a safe way to access the top for maintenance.
- Use a fixed ladder or tubing with welded steps.
Electrical System and Storage
Careful planning of the electrical system ensures optimal power generation and safe operation.
Wire Runs
- Use 10-12 AWG copper wire for all connections.
- Seal connections to prevent corrosion.
Power Regulation
- Use a charge controller to prevent battery overcharge.
- A dump load diverts excess power as heat.
Battery Bank
- Wire multiple batteries together for more storage.
- Use deep cycle lead-acid batteries suited for solar systems.
Safety
- Install an isolator switch and breakers.
- Use insulated connections and grounded equipment.
- Bury cables at adequate depth.
Installation and Testing
Follow safety precautions when installing your wind turbine. Test it thoroughly before permanent operation.
Balance and Alignment
- Check that the rotor spins smoothly without wobbling.
- Align the turbine into the prevailing wind direction.
Startup and Shutdown
- Start at low wind speeds and power output.
- Use a brake to stop the rotor for maintenance.
Monitoring Performance
- Record wind speed, voltage and power output.
- Check for vibration, noise and overheating.
Building your own wind turbine is an ambitious but rewarding project. With persistence and care in designing, constructing and installing the system, you can successfully harness wind energy using scrap materials.