True or False: The lowest wind speed that can typically be measured with a modern cup anemometer is 0.5 m/s (1.6 ft/s).

True or False: The lowest wind speed that can typically be measured with a modern cup anemometer is 0.5 m/s (1.6 ft/s).

• A. True
• B. False
• C. Not sure
• D. Cannot determine

Answer: (A)

Start-up threshold for a cup anemometer is the key concept here. Because the rotor must overcome static friction and bearing inertia, there is a minimum wind speed at which it will begin to rotate and produce a measurable signal. In many modern cup anemometers, this cut-in or minimum usable wind speed is around 0.5 m/s (about 1.6 ft/s). Below this, the rotor tends to stall or produce readings overwhelmed by noise, so reliable, usable measurements aren’t obtained. While some highly sensitive setups can operate a bit lower, 0.5 m/s is a common practical lower limit for typical devices, making the statement true.

Start-up threshold for a cup anemometer is the key concept here. Because the rotor must overcome static friction and bearing inertia, there is a minimum wind speed at which it will begin to rotate and produce a measurable signal. In many modern cup anemometers, this cut-in or minimum usable wind speed is around 0.5 m/s (about 1.6 ft/s). Below this, the rotor tends to stall or produce readings overwhelmed by noise, so reliable, usable measurements aren’t obtained. While some highly sensitive setups can operate a bit lower, 0.5 m/s is a common practical lower limit for typical devices, making the statement true.