QUESTION: How do I tell if my anemometer bearing needs replacing?
ANSWER: The easiest way to tell if your anemometer bearings need replacement is to observe the anemometer rotation as it slowly comes to a stop. The low wind conditions which are required for an anemometer to come to a stop usually occur during sunrise and sunset when winds tend to die down, so plan your service trips accordingly.
It is also possible to look at the anemometer data to diagnose if a bearing needs replacing. For this, a sampling interval of less than 2 seconds is necessary. A trained eye can look at the behavior of the anemometer slow down and compare it to another anemometer whose bearings are known to be clean and in good condition. Very low wind conditions are also required.