Question 1
Fatigue testing of rotor blades subject the blades to an oscillation in _______ direction.
A. horizontal
B. vertical
C. flapwise
D. diagonal
View Answer
Answer: Option C
Explanation:
During fatigue testing of rotor blades, they are oscillated in the flapwise direction for millions of cycles. A typical flapwise test takes about three hours. Depending on the results of a fatigue test, we comment on whether a rotor blade can withstand high wind speeds or not.
Answer: Option C
Explanation:
During fatigue testing of rotor blades, they are oscillated in the flapwise direction for millions of cycles. A typical flapwise test takes about three hours. Depending on the results of a fatigue test, we comment on whether a rotor blade can withstand high wind speeds or not.
Question 2
Nacelle is a kiosk that houses ______
A. a MOSFET
B. a diode
C. a wifi router
D. a yaw drive
View Answer
Answer: Option D
Explanation:
Nacelle is a big box that houses various components like power converter, yaw drive, gearbox, etc. MOSFETs and diodes are discrete electrical components used to realize various electrical and electronic circuits. Nacelle does not house a Wi-Fi router.
Answer: Option D
Explanation:
Nacelle is a big box that houses various components like power converter, yaw drive, gearbox, etc. MOSFETs and diodes are discrete electrical components used to realize various electrical and electronic circuits. Nacelle does not house a Wi-Fi router.
Question 3
Offshore wind turbines are not erected in water bodies.
A. FALSE
B. TRUE
View Answer
Answer: Option A
Explanation:
Offshore wind turbines are erected in water bodies like oceans or continental shelves. They are used to harvest energy from winds flowing above the water bodies. They generate about 40% more electricity as compared to other wind turbines on land.
Answer: Option A
Explanation:
Offshore wind turbines are erected in water bodies like oceans or continental shelves. They are used to harvest energy from winds flowing above the water bodies. They generate about 40% more electricity as compared to other wind turbines on land.
Question 4
What are horizontal wind turbines?
A. Wind turbines are rotate about an axis perpendicular to the plane of ground
B. Wind turbines are rotate about an axis diagonal to the plane of ground
C. Wind turbines are rotate about an axis 30 degrees to the plane of ground
D. Wind turbines are rotate about an axis parallel to the plane of wind streamlines
View Answer
Answer: Option D
Explanation:
Horizontal wind turbines are made up of blades that rotate about an axis parallel to the plane of wind streamlines. Hence, they are also called as Horizontal Axis Wind Turbines (HAWT). They are the most popularly used wind turbines for commercial wind energy harvesting applications.
Answer: Option D
Explanation:
Horizontal wind turbines are made up of blades that rotate about an axis parallel to the plane of wind streamlines. Hence, they are also called as Horizontal Axis Wind Turbines (HAWT). They are the most popularly used wind turbines for commercial wind energy harvesting applications.
Question 5
What are the types of VAWT?
A. Lift, horizontal
B. Horizontal, vertical
C. Drag, lift
D. Urban wind turbines
View Answer
Answer: Option C
Explanation:
There are two types of VAWT – drag and lift. Horizontal and vertical wind turbines are classified based on their axis of rotation. Urban wind turbines are specially designed turbines to harvest wind energy in cities and other urban areas.
Answer: Option C
Explanation:
There are two types of VAWT – drag and lift. Horizontal and vertical wind turbines are classified based on their axis of rotation. Urban wind turbines are specially designed turbines to harvest wind energy in cities and other urban areas.
Question 6
What is a downwind turbine?
A. Rotor is positioned at the three-quarters of the height of the tower
B. Rotor of the turbine is in front of the unit
C. Rotor is positioned at the bottom of the tower
D. Rotor of the turbine is behind the unit
View Answer
Answer: Option D
Explanation:
A downwind turbine is a type of wind turbine where the rotor is positioned behind the tower. The nacelle used is typically designed to seek the wind.
Answer: Option D
Explanation:
A downwind turbine is a type of wind turbine where the rotor is positioned behind the tower. The nacelle used is typically designed to seek the wind.
Question 7
What is a hybrid type tower?
A. Guyed tower
B. Guyed tower and wooden tower
C. Thin and tall lattice type guyed tower
D. Guyed tower and electric pole
View Answer
Answer: Option C
Explanation:
Unlike the guyed tower which uses a single pole, the hybrid tower uses a thin and tall lattice type tower that is supported by guy cables. It is a hybrid of both, lattice type and guyed type towers.
Answer: Option C
Explanation:
Unlike the guyed tower which uses a single pole, the hybrid tower uses a thin and tall lattice type tower that is supported by guy cables. It is a hybrid of both, lattice type and guyed type towers.
Question 8
What is a pitch drive motor?
A. A motor that senses wind direction
B. A motor to control the angle of blades
C. A motor to ensure nacelle faces in the direction of the wind
D. A motor to rotate the blades
View Answer
Answer: Option B
Explanation:
A pitch drive motor is a motor used to control the angle of blades. Pitching is the process of rotating the angle of blades to cut maximum wind for harvesting energy.
Answer: Option B
Explanation:
A pitch drive motor is a motor used to control the angle of blades. Pitching is the process of rotating the angle of blades to cut maximum wind for harvesting energy.
Question 9
What is a vertical wind turbine?
A. Wind turbines are rotate about an axis perpendicular to the plane of wind streamlines
B. Wind turbines are rotate about an axis diagonal to the plane of ground
C. Wind turbines are rotate about an axis 30 degrees to the plane of ground
D. Wind turbines are rotate about an axis parallel to the plane of ground
View Answer
Answer: Option A
Explanation:
Vertical wind turbines are made up of blades that rotate about an axis perpendicular to the plane of wind streamlines. Hence, they are also called as Vertical Axis Wind Turbines (HAWT). Most of its main components is near the ground unlike a HAWT.
Answer: Option A
Explanation:
Vertical wind turbines are made up of blades that rotate about an axis perpendicular to the plane of wind streamlines. Hence, they are also called as Vertical Axis Wind Turbines (HAWT). Most of its main components is near the ground unlike a HAWT.
Question 10
What is a yaw drive?
A. A device used to support and stabilize other components
B. A device used to house various energy conversion components
C. A motor to ensure that nacelle faces the wind
D. A device used to track wind direction
View Answer
Answer: Option C
Explanation:
A yaw drive is a motor to ensure that the nacelle faces in the direction of the wind. This advocates maximum energy extraction from the incoming wind. It is controlled by a PLC that uses wind vane to track the net direction of wind.
Answer: Option C
Explanation:
A yaw drive is a motor to ensure that the nacelle faces in the direction of the wind. This advocates maximum energy extraction from the incoming wind. It is controlled by a PLC that uses wind vane to track the net direction of wind.
Question 11
What is an upwind turbine?
A. Rotor of the turbine is behind the unit
B. Rotor of the turbine is in front of the unit
C. Rotor is positioned at the bottom of the tower
D. Rotor is positioned at the center of the tower
View Answer
Answer: Option B
Explanation:
An upwind turbine is a type of wind turbine where the rotor is positioned in front of the unit. The position is similar to that of propellers used in airplanes. Most of the wind turbines used commercially are upwind turbines.
Answer: Option B
Explanation:
An upwind turbine is a type of wind turbine where the rotor is positioned in front of the unit. The position is similar to that of propellers used in airplanes. Most of the wind turbines used commercially are upwind turbines.
Question 12
What is the cost of a wind turbine per megawatt?
A. $10000
B. $1000
C. $100
D. $1 million
View Answer
Answer: Option D
Explanation:
As of 2019, a wind turbine costs about $1 million per megawatt. Manufacturing the rotor blades consume most of the budget. Depending on the size and material used, the cost may vary. For example, carbon fibre is expensive when compared to glass fibre.
Answer: Option D
Explanation:
As of 2019, a wind turbine costs about $1 million per megawatt. Manufacturing the rotor blades consume most of the budget. Depending on the size and material used, the cost may vary. For example, carbon fibre is expensive when compared to glass fibre.
Question 13
What is the main advantage of a vertical axis wind turbine?
A. Directional and sensitive to wind turbulence
B. Not directional and sensitive to wind turbulence
C. Directional and insensitive to wind turbulence
D. Not directional and insensitive to wind turbulence
View Answer
Answer: Option D
Explanation:
VAWTs are made up of blades that rotate about an axis perpendicular to the plane of streamlines. Hence, their main advantage is that they are insensitive to wind turbulences and are not directional.
Answer: Option D
Explanation:
VAWTs are made up of blades that rotate about an axis perpendicular to the plane of streamlines. Hence, their main advantage is that they are insensitive to wind turbulences and are not directional.
Question 14
What is the main advantage of an upwind turbine?
A. Increased tower shadow effect
B. Reduced tower shadow effect
C. No tower shadow effect
D. Manufacturing
View Answer
Answer: Option B
Explanation:
Tower shadow effect occurs when the tower acts as an obstruction between the blades and the wind. In an upwind turbine, both rotor and blades are attached in front of tower. Thus, the tower shadow effect reduces considerably.
Answer: Option B
Explanation:
Tower shadow effect occurs when the tower acts as an obstruction between the blades and the wind. In an upwind turbine, both rotor and blades are attached in front of tower. Thus, the tower shadow effect reduces considerably.
Question 15
What is the main advantage of any downwind turbine?
A. Inflexible rotor blades
B. Flexible rotor blades
C. Position of the rotor
D. Reduced tower shadow effect
View Answer
Answer: Option B
Explanation:
The main advantage of a downward turbine is that the rotor blades can be made flexible. This reduces the cost of manufacturing and relieves stress on the tower at high wind speeds.
Answer: Option B
Explanation:
The main advantage of a downward turbine is that the rotor blades can be made flexible. This reduces the cost of manufacturing and relieves stress on the tower at high wind speeds.
Question 16
What is the main disadvantage of a downward wind turbine?
A. Increased tower shadow effect
B. Flexible rotor blades
C. Inflexible rotor blades
D. Bending of blades at high wind speeds
View Answer
Answer: Option B
Explanation:
Since the rotor of a downward wind turbine is placed behind the tower, it experiences an increased tower shadow effect. Flexible rotor blades enable bending at high wind speeds. This is its main advantage.
Answer: Option B
Explanation:
Since the rotor of a downward wind turbine is placed behind the tower, it experiences an increased tower shadow effect. Flexible rotor blades enable bending at high wind speeds. This is its main advantage.
Question 17
What is the main disadvantage of a horizontal axis wind turbine?
A. Easy operation at near ground winds
B. Does not self-start
C. Difficult operation at near ground winds
D. High starting torque
View Answer
Answer: Option C
Explanation:
The main disadvantage of any horizontal wind axis turbine is that it cannot be operated at near ground winds. This is due to the height of the tower and size of the blades. However, most of them are self-starting and do not have a high starting torque.
Answer: Option C
Explanation:
The main disadvantage of any horizontal wind axis turbine is that it cannot be operated at near ground winds. This is due to the height of the tower and size of the blades. However, most of them are self-starting and do not have a high starting torque.
Question 18
What is the main disadvantage of a vertical axis wind turbine?
A. Not directional and insensitive to wind turbulence
B. More drag than HAWTs
C. Less drag than HAWTs
D. High starting torque
View Answer
Answer: Option B
Explanation:
Vertical wind axis turbines cause more drag than HAWTs as their blades are constantly spinning back into the wind. Their main advantage is that they are not directional and insensitive to wind turbulence. Also, they have a low starting torque and may require an external source to start turning.
Answer: Option B
Explanation:
Vertical wind axis turbines cause more drag than HAWTs as their blades are constantly spinning back into the wind. Their main advantage is that they are not directional and insensitive to wind turbulence. Also, they have a low starting torque and may require an external source to start turning.
Question 19
What is the main disadvantage of an upwind turbine?
A. Increased tower shadow effect
B. Reduced tower shadow effect
C. A rotor that needs to be placed at some distance from the tower
D. An inflexible rotor that needs to be placed close to the tower
View Answer
Answer: Option C
Explanation:
The main disadvantage of any upwind turbine is the requirement of placing the rotor at some distance from the tower. This setup prevents problems with a blade strike. They also require a yaw mechanism to ensure that the rotor faces the wind continuously.
Answer: Option C
Explanation:
The main disadvantage of any upwind turbine is the requirement of placing the rotor at some distance from the tower. This setup prevents problems with a blade strike. They also require a yaw mechanism to ensure that the rotor faces the wind continuously.
Question 20
What is the main function of gearbox in a wind turbine system?
A. Multiples rotation speed to generate electricity
B. Divides rotation speed to generate electricity
C. Multiples rotation speed to consume wind energy
D. Divides rotation speed to consume wind energy
View Answer
Answer: Option A
Explanation:
The blades rotate slowly and this speed is not sufficient to generate electricity. So, the main function of a gearbox in a wind turbine system is to multiply the rotation speed to a sufficiently high level so as to generate electricity.
Answer: Option A
Explanation:
The blades rotate slowly and this speed is not sufficient to generate electricity. So, the main function of a gearbox in a wind turbine system is to multiply the rotation speed to a sufficiently high level so as to generate electricity.
Question 21
What is the main function of tower in a wind turbine system?
A. Acts a support to all other components used in wind turbine system
B. Acts as an antenna for wireless radio communications
C. Acts as an electric pole for power transportation
D. Destabilizes the wind turbine system
View Answer
Answer: Option A
Explanation:
The main function of tower in a wind turbine system is to support the other components. It also stabilizes both, the rotor and blades which eventually convert wind energy to electrical energy via mechanical energy.
Answer: Option A
Explanation:
The main function of tower in a wind turbine system is to support the other components. It also stabilizes both, the rotor and blades which eventually convert wind energy to electrical energy via mechanical energy.
Question 22
Which of the following are commonly used commercial wind turbines?
A. Vertical and DFIG
B. Horizontal and SCIG
C. Horizontal and vertical
D. DFIG and SCIG
View Answer
Answer: Option C
Explanation:
Horizontal axis wind turbines (HAWT) or horizontal and vertical axis wind turbines (VAWT) or vertical are commonly used commercial wind turbines. DFIG, SCIG and PMSG are commercially used power generators for wind energy.
Answer: Option C
Explanation:
Horizontal axis wind turbines (HAWT) or horizontal and vertical axis wind turbines (VAWT) or vertical are commonly used commercial wind turbines. DFIG, SCIG and PMSG are commercially used power generators for wind energy.
Question 23
Which of the following are the major parts of a wind turbine system?
A. Tower, rotor, water storage tank, air compressor
B. Tower, rotor and blades, air compressor, vacuum pump, electricity generator
C. Electricity generator, nacelle, rotor and blades, power converter, building
D. Tower, nacelle, rotor and blades, power converter, electricity generator
View Answer
Answer: Option D
Explanation:
Tower, nacelle, rotor and blades, power converter, electricity generator and wind shaft are the major parts of a wind turbine system. Water storage tank, air compressor and vacuum pump are not used in a wind turbine system.
Answer: Option D
Explanation:
Tower, nacelle, rotor and blades, power converter, electricity generator and wind shaft are the major parts of a wind turbine system. Water storage tank, air compressor and vacuum pump are not used in a wind turbine system.
Question 24
Which of the following components of a wind turbine system is arranged in the order in which energy is being converted?
A. Blades – rotor – electric generator – shaft
B. Blades – rotor – shaft – electric generator
C. Shaft – blades – rotor – electric generator
D. Electric generator – blades – rotor — shaft
View Answer
Answer: Option B
Explanation:
A wind turbine system first converts wind energy to mechanical energy and then to electrical energy using an electric generator. The correct order is blades – rotor – shaft – electric generator.
Answer: Option B
Explanation:
A wind turbine system first converts wind energy to mechanical energy and then to electrical energy using an electric generator. The correct order is blades – rotor – shaft – electric generator.
Question 25
Which of the following is an advantage of a horizontal axis wind turbine?
A. Blades are to the side of turbine’s center of gravity
B. Blades are parallel to the vertical axis passing through the turbine’s center of gravity
C. Blades are parallel to the horizontal axis passing through the turbine’s center of gravity
D. Blades are positioned perpendicular to the plane of the ground
View Answer
Answer: Option A
Explanation:
In a horizontal axis wind turbine (HAWT), the blades are positioned to the side of the turbine’s center of gravity. This provides stability to the entire setup. Blades rotate to an axis parallel to the plane of ground.
Answer: Option A
Explanation:
In a horizontal axis wind turbine (HAWT), the blades are positioned to the side of the turbine’s center of gravity. This provides stability to the entire setup. Blades rotate to an axis parallel to the plane of ground.
Question 26
Which of the following materials are used to make a rotor blade of a wind turbine?
A. Glass fibre reinforced polyester
B. Salt
C. Sugar
D. Plastic
View Answer
Answer: Option A
Explanation:
Rotor blades are made using glass fibre reinforced polyester (GRP). It is a material made impregnating a matrix of fibre glass mats with a polyester. This polyester is hardened after impregnation.
Answer: Option A
Explanation:
Rotor blades are made using glass fibre reinforced polyester (GRP). It is a material made impregnating a matrix of fibre glass mats with a polyester. This polyester is hardened after impregnation.
Question 27
Which of the following materials can be used to make a rotor blade of a wind turbine apart from glass fibre reinforced polyester (GRP)?
A. Silicon, germanium
B. Epoxy, carbon fibre
C. Plastic
D. Salt
View Answer
Answer: Option B
Explanation:
Apart from GRP, epoxy and carbon fibre can be used to make rotor blades. Though carbon fibre is lighter and has higher material strength, it is expensive. Silicon and germanium are generally used in semiconductor industry.
Answer: Option B
Explanation:
Apart from GRP, epoxy and carbon fibre can be used to make rotor blades. Though carbon fibre is lighter and has higher material strength, it is expensive. Silicon and germanium are generally used in semiconductor industry.
Question 28
Which of the following towers is used for small wind turbines?
A. Hybrid tower
B. Guyed pole tower
C. Electric pole
D. Wooden pole
View Answer
Answer: Option B
Explanation:
The guyed pole tower is used for small wind turbines. It is a single vertical pole supported by guy cables from different sides. An electric pole is specifically used for electricity transportation. Wooden pole is a general purpose pole and can be used for a variety of applications.
Answer: Option B
Explanation:
The guyed pole tower is used for small wind turbines. It is a single vertical pole supported by guy cables from different sides. An electric pole is specifically used for electricity transportation. Wooden pole is a general purpose pole and can be used for a variety of applications.
Question 29
Wind turbines convert wind energy to ________
A. mechanical energy
B. electrical energy
C. heat energy
D. solar energy
View Answer
Answer: Option A
Explanation:
Wind turbines convert wind energy to mechanical energy. This mechanical energy is then converted to electrical energy using an electric generator. They neither convert wind energy to heat energy nor to solar energy.
Answer: Option A
Explanation:
Wind turbines convert wind energy to mechanical energy. This mechanical energy is then converted to electrical energy using an electric generator. They neither convert wind energy to heat energy nor to solar energy.
Question 30
Wind turbines require regular maintenance.
A. FALSE
B. TRUE
View Answer
Answer: Option B
Explanation:
Wind turbines require regular maintenance to ensure reliability and maintain initial efficiency. They are generally serviced after 3-4 months of usage. In best case, they are available to generate energy 98% of the time.
Answer: Option B
Explanation:
Wind turbines require regular maintenance to ensure reliability and maintain initial efficiency. They are generally serviced after 3-4 months of usage. In best case, they are available to generate energy 98% of the time.