Title: Module 2 Test, Part 2
Course: WIND 100WH Introduction to Wind Energy > Section: WIND 100WH Introduction to Wind Energy

Q: When pressure on the top of the airfoil is less than the pressure at the bottom of the airfoil, __________ is created.
- lift
- thrust
- angle of attack
- force
A: lift

Q: Airfoils have two sides. What are they called?
- Pitch and stall sides
- Angle of attach and furling sides
- Leading edge and trailing edge
- Vector face and the scalar edge
A: Leading edge and trailing edge

Q: When an airfoil has no lift and is nearly flat, _________occurs.
- thrust
- turbulence
- stall
- attack
A: stall

Q: During pitch control, what device associated with the control system is used to adjust the operating speed of the rotor?
- Actuator assembly
- PLC
- Anemometer
- Pedometer
A: Anemometer

Q: What’s it called when a blade's pitch has been changed to the point it begins to stall?
- Stall control
- Pitch control
- Furling
- Stalled pitch
A: Furling

Q: What type of control system helps stop a turbine from over speeding in high winds?
- Airfoil
- Pitch regulated
- Passive control
- Looped data control
A: Passive control

Q: On a stall-regulated wind turbine, the blades are generally zero-angled and the rotor is __________ in high winds.
- pitch controlled
- stall controlled
- locked
- folded up
A: locked

Q: Drag on a blade is always on the ______________.
- leading edge of the blade
- trailing edge of the blade
- stall control related to the blade
- drag coefficient metering devices
A: leading edge of the blade

Q: In order to have the best aerodynamics for a blade, the drag coefficient must be _____.
- high
- low
- more than 59%
- none of above
A: low

Q: The blade of a wind turbine must be structured properly so that its _____ does not destroy it.
- resonance
- turbulence factors
- stressing factors
- centrifugal force
A: centrifugal force

Q: On an upwind-style HAWT, the blades need to be more _________ to withstand the force of high winds.
- pliable
- fixed
- rigid and inflexible
- low profile
A: rigid and inflexible

Q: The pitch system helps control the rotor speed on a wind turbine by _____.
- bending the blades
- shortening the length of the blades
- applying the brakes
- pivoting the blades to catch less or more of the wind
A: pivoting the blades to catch less or more of the wind

Q: Wind turbines may use ac or DC generators. The DC generator’s output must be changed to ____ Hz ac for connection to the U.S. grid.
- 50
- 16.6
- 500
- 60
A: 60

Q: On a HAWT, where’s the generator typically located?
- At the top, within the nacelle
- In the top tower section right below the yaw deck
- Always at the bottom of the tower
- Below the nacelle, connected by a vertical shaft
A: At the top, within the nacelle

Q: On a HAWT, the turbine blades and rotor are always mounted before the _____.
- high-speed shaft assembly
- low-speed shaft assembly
- high-speed coupling assembly
- gearbox
A: low-speed shaft assembly

Q: Most commercial HAWTs are designed to have how many blades?
- Two blades
- Four blades
- Two or three blades
- None of the above
A: Two or three blades

Q: With the blades of the rotor pitched greatly, the production of electricity _____.
- increases
- decreases
A: decreases

Q: The blade pitch angle at which wind power absorption is best is called the _____ and the blades would be considered to be at _____ pitch.
- angle of incidence / maximum
- angle of velocity / minimum
- power angle / critical
- critical angle / full
A: critical angle / full

Q: Blade pitch control is utilized in both high and low winds.
- True
- False
A: True

Q: In what position must the wind turbine blades be placed when maintenance is to be performed?

Q: Wind turbine blades are designed to withstand many variables of stress. List three of these variables.

Q: What is an advantage of the Darrieus wind turbine over the Savonius wind turbine?

Q: What type of turbine is the Savonius wind turbine?

Q: What are the two styles (or subtypes) of HAWTs?

Q: Concerning HAWTs, what are two main advantages of the three-blade design over the two-blade design?