WTT Wind Turbine Components & Design 2 — Questions and Answers
Question 1: What is the purpose of the pitch control system on a variable-pitch wind turbine?
- To adjust blade angle to optimize power output and protect against high winds (Correct answer)
- To control the rotational speed of the generator directly
- To align the nacelle with the wind direction
- To regulate voltage output from the generator
Correct answer: To adjust blade angle to optimize power output and protect against high winds
Pitch control adjusts the angle of each blade to maximize energy capture at low winds and feather blades to protect the turbine during high-wind conditions.
Question 2: Which type of gearbox configuration is most commonly used in modern multi-stage wind turbine drivetrains?
- Planetary-helical combination (Correct answer)
- Worm gear single-stage
- Bevel gear single-stage
- Chain-drive reduction
Correct answer: Planetary-helical combination
A planetary-helical combination gearbox is favored because it provides high torque density in the planetary stage and smooth operation in the helical stages.
Question 3: What material is most commonly used for utility-scale wind turbine blades today?
- Fiberglass-reinforced polymer (GFRP) (Correct answer)
- Carbon steel sheet metal
- Solid wood laminate
- Aluminum alloy extrusion
Correct answer: Fiberglass-reinforced polymer (GFRP)
Glass fiber reinforced polymer (GFRP) is the dominant blade material due to its excellent strength-to-weight ratio, fatigue resistance, and cost-effectiveness.
Question 4: What does 'swept area' refer to in wind turbine specifications?
- The circular area traced by the rotating blades (Correct answer)
- The floor area of the nacelle service platform
- The land area required for turbine installation
- The surface area of the tower exterior
Correct answer: The circular area traced by the rotating blades
Swept area is the circular disc traced by blade tips during rotation; it directly determines how much wind energy the turbine can intercept.
Question 5: Which component connects the rotor hub to the main shaft in a direct-drive wind turbine?
- The hub is bolted directly to the main shaft or integrated into it (Correct answer)
- A fluid coupling unit
- A torque converter assembly
- A magnetic clutch plate
Correct answer: The hub is bolted directly to the main shaft or integrated into it
In direct-drive turbines, the hub is bolted or structurally integrated directly to the main shaft, eliminating the gearbox entirely.
Question 6: What is the function of the bedplate (mainframe) inside a wind turbine nacelle?
- It is the structural chassis that supports and aligns all drivetrain and nacelle components (Correct answer)
- It converts mechanical energy to electrical energy
- It houses the pitch control electronics
- It stores hydraulic fluid for the braking system
Correct answer: It is the structural chassis that supports and aligns all drivetrain and nacelle components
The bedplate is the main structural frame inside the nacelle that carries the weight of the drivetrain, generator, and other components while maintaining precise alignment.
Question 7: A wind turbine's cut-out wind speed is the speed at which the turbine:
- Shuts down to prevent structural or mechanical damage (Correct answer)
- Reaches its rated power output
- Begins generating electricity for the first time
- Switches from variable to fixed pitch operation
Correct answer: Shuts down to prevent structural or mechanical damage
Cut-out wind speed is the upper threshold—typically 25 m/s—at which the turbine shuts down automatically to protect it from storm damage.
WTT Wind Turbine Components & Design 2
What is the purpose of the pitch control system on a variable-pitch wind turbine?