Small Wind Installer Flashcards
7 cards from real NABCEP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Small Wind Installer flashcards as text
What is the generally recommended minimum average annual wind speed for a cost-effective small wind turbine installation?
Answer: 10 mph (4.5 m/s)
A minimum average annual wind speed of approximately 10 mph (4.5 m/s) is generally required for a small wind system to be economically viable.
Wind power is proportional to the cube of wind speed. If wind speed doubles, how does the available power in the wind change?
Answer: It increases by a factor of eight
Because wind power follows P ∝ V³, doubling the wind speed increases available power by 2³ = 8 times.
Which instrument is the primary tool used to measure wind speed during a small wind site assessment?
Answer: Anemometer
An anemometer measures wind speed and is the standard instrument used in wind resource assessments to collect site data.
Per the widely accepted '30-foot rule,' how much taller should a small wind turbine hub be above any obstruction within 500 feet of the installation?
Answer: 30 feet
The 30-foot rule states a turbine hub should be at least 30 feet above any obstruction within 500 feet to avoid turbulent wake effects that reduce output and increase fatigue loads.
What is the Rayleigh distribution used for in small wind site assessment?
Answer: Modeling the statistical frequency of wind speeds at a site
The Rayleigh distribution is a statistical model that estimates how often each wind speed occurs at a site, enabling annual energy production estimates.
What is a wind shadow (turbulence zone) that forms downwind of an obstruction such as a building or tree line?
Answer: A zone of reduced and turbulent airflow extending 10–20 times the height of the obstruction downwind
Obstacles create a turbulent wake zone extending 10–20 times their height downwind, which degrades energy output and increases mechanical fatigue on turbines sited within it.
Which of the following best describes a 'furling' mechanism on a small horizontal-axis wind turbine?
Answer: A passive system that turns the rotor out of the wind to prevent overspeed in high winds
Furling is a passive overspeed protection mechanism in which the tail folds or the rotor yaws sideways, reducing swept area exposure when wind speeds exceed safe operating limits.