Tips for Building A Windmill Generator

Windmill in the landscape
  • 2-30 hours
  • Intermediate
  • 20-500

Building a windmill generator is one way of trying to ease your power bills. The task is not that difficult, but you must have a good set of plans or a blueprint. Many hobby shops will be able to supply the plans.

1. The Generator

The central element of the windmill generator is the power generator itself. Ideally you need a DC permanent magnet motor which is rated for high voltage and low revolutions.

2. The Fan

To collect the wind, you need to have a fan or propeller. This can be made up from a kit or carved from plastic or balsa wood. The fan will have to be tested to find the best length for the blades. Without a blueprint this will be done by trial and error. Once you've chosen the fan blade size, the fan will need balancing. This can be done by carefully shaving a heavy blade until there is balance. For most home wind generators, a triple blade fan is ideal.

3. The Nacelle

The generator will need to be in a waterproof nacelle. For most motors, a piece of PVC tubing is ideal because it can be tightened against the motor with large jubilee clips. The back and front of the nacelle will need to be closed. A piece of rigid plastic or rubber sheet will do that. The front cover will need to be drilled to accommodate the drive shaft of the motor.

4. Fitting the Fan to the Generator


The fan has to be fitted to the drive shaft of the DC motor. This can be achieved using a dual female coupling. If the motor drive shaft is threaded it might be possible to use those threads.

5. The Tail Assembly

To keep the generator facing into the wind a tail will have to be built and fitted to the nacelle. Part of the tail assembly will also be the pivot on which the generator will swing. This will attach to a vertical pipe that will be fitted to the top of the generator tower.

6. The Tower

You will need to get your windmill generator into the best flow of air available. You might be able to use a roof ridge or a wall bracket. The tower will have to be tall enough and secure enough. There is the possibility of buying a tower structure from a surplus store.

7. The Electricity Store

Once the generator is ready to be used you need to have a battery or system of batteries to store the power you generate. Heavy duty car batteries would be very useful for this. Between the batteries and the generator you need to fit a diode to stop the power being returned to the generator. This would waste your power and turn the generator back into a motor that would drive the fan.

With the blueprint, building a wind generator is within the capacity of most house holders. Finding the parts might take a while but will be well worth it.