Introduction
Installing a micro wind turbine at your home using scrap materials can reduce your dependence on the electric grid and lower your energy bills. Small wind turbines are an economical and sustainable way to generate electricity. This guide will walk you through the process of building a micro wind turbine from scrap parts and integrating it into your home's electrical system.
Assessing Your Location
The first step is determining if your location has adequate wind resources. Ideal sites for small wind turbines have average annual wind speeds of at least 10 mph. You can obtain wind speed data for your area from the National Renewable Energy Laboratory.
Consider mounting the turbine on a rooftop, ridge, or hilltop that gets unobstructed wind. Obstacles like trees and buildings can create turbulence and reduce output. The turbine should be sited upwind of structures.
Sourcing Materials
Many components for a micro wind turbine can be salvaged from scrap parts. Useful materials to collect include:
- Alternator - Auto, boat, wind turbine alternators can be adapted
- Blades - Metal, wood, plastic blades from ventilation fans
- Hub - Metal hubs from old machinery, pulleys, gears
- Tail - Metal or wood from scrap lumber
- Tower - Electrical conduit, torsion tubes, metal poles
- Bolts, screws, wiring - Salvage reusable fasteners and electrical wiring
Check scrap yards, automotive shops, and online classifieds when sourcing used parts. Custom fabricating blades or other components may be necessary.
Design Considerations
Factors to consider in your wind turbine design:
- Number of blades - Two or three blades are most common
- Rotor diameter - Larger blades capture more wind energy. 8-10 feet diameter is typical.
- Alternator - Select for high efficiency and low start-up wind speeds
- Tower height - Standard height is 30-50 feet above obstacles
- Safety features - Install guy wires, grounding, overspeed controls
Aim for a simple and robust design using the materials you have available. Keeping the turbine balanced and symmetrical will improve performance.
Alternator Rewiring
Most auto alternators require rewiring to function with a wind turbine. Use the following steps:
- Disconnect all wiring from the alternator terminals
- Connect the + and - terminals directly together
- Wire the stator leads together in parallel
- Connect the field wires together without touching the rotor
- Connect the field wires to an external bridge rectifier
- Wire the rectifier outputs to a charge controller
This allows the alternator to self-excite and maximize power generation.
Tower and Foundation
The tower raises the turbine above obstructions to reach stronger wind. Several options exist for scrap-built towers:
- Tubular tower - Assemble electrical conduit or torsion tubes
- Tilt-up pole - Use a metal pole that can tilt up for service
- Guyed pole - Support a tall wood pole with guy wires
Anchor the tower base to a concrete pad or pier foundation for stability. The foundation should extend 3-4 feet underground in climates with frost heave.
Installation and Wiring
Follow these steps to install your micro wind turbine:
- Assemble the turbine components on the ground
- Raise the tower into position and anchor the base
- Attach the turbine to the top of the tower
- Run wiring from the turbine down inside the tower
- Connect the turbine output to a charge controller
- Connect the charge controller to batteries and/or your home's electrical panel
All wiring connections should be soldered and insulated. Seek help from an electrician if unsure.
Operations and Maintenance
Routine maintenance is crucial for maximizing power production and longevity:
- Inspect bolts, brackets, and electrical connections periodically for tightness and corrosion
- Check guy wires and grounding for damage
- Clean debris from blades and prevent ice buildup in cold climates
- Lubricate bearings annually
- Check power output and battery charging regularly
Take safety precautions when servicing the turbine. Larger repairs may be needed over time.
Conclusion
Constructing a micro wind turbine from scrap materials takes some mechanical skill but can provide clean energy and savings on electricity bills. This guide covers key steps such as finding parts, tower designs, installation, and maintenance. With careful planning and patience, you can convert components headed for the junkyard into a functioning home wind turbine.