Know the Technology – The Parts of a Windmill

Wood Profits Banner

You’ve decided to take the plunge and install an electricity-producing windmill (a.k.a. wind turbine) on your property. You may be building it yourself, or may have hired a company to do that part for you. But, there’s one thing you can’t escape – you really need to know some things about your windmill!

Listed below are the major components of a windmill. It won’t take much time to familiarize yourself with these key components, so you can “talk the talk” when it comes to the parts of a windmill.


This is essentially a speedometer for the windmill – a gauge to tell how fast the blades are rotating. Some more sophisticated systems have a feedback loop so the anemometer will “talk” to the control computer, regulating the blades’ speed so damage won’t occur.


Most turbines have at least two blades, similar to the halves of a airplane’s propeller. Many windmills have more than two blades. Wind impacts these blades, causing “lift,” making the windmill rotate.


More expensive windmills have a brake. The brake can be applied to stop the windmill in an emergency.


Again, more expensive and sophisticated wind turbines (proper name for a windmill that generates electrical power) have a computerized controller. One function of the controller is to start and stop the windmill. Normally, winds less than 8 miles per hour don’t generate any electricity, and winds greater that 55 mph can damage to the windmill. The computer lets the windmill operate between these velocities.

Gear Box

Some larger windmills have gearboxes, usually to increase the shaft speed from 60 rpm to a maximum of 1800 revolutions per minute. As these gearboxes can cost a lot, and can have high rates of failure, windmill engineers are always looking for ways to go “gearless” – meaning direct-drive. That saves money and makes the windmills much simpler.


This is the part that actually makes the electricity. Similar to the alternator (or generator) in your car, the generator makes the electrical power.


This is a fancy French name for the cover that protects the generator and gearbox (if included).


Pitch is the “tilt” of the blades, or the angle that the blades are at to “capture” the wind so the generator will rotate. Too much pitch can make the generator turn too fast and damage the windmill.


The rotor is attached to the generator shaft and also holds the blades and hub.


The tower can be made of wood on the smaller windmills, and is usually made of steel or aluminum on the larger units. This is what holds the windmill up into the airflow.

Wind Vane

This is the “tail” that helps keep the windmill pointed into the wind. Very important for maximum power generation.

Now you know some of the basic parts of a windmill. While this list is far from everything you’ll find on an electricity-producing windmill, at least you’ll have some ideas what other windmill enthusiasts are talking about.

Source by Stephen J. Thomas