This set of Energy Engineering Questions and Answers for Aptitude test focuses on “Components of Wind Energy Conversion System”.
1. How much power does the small scale wind machine generate?
a) 18 KW
b) 2 KW
c) 12 KW
d) 30 KW
Explanation: These might be used on farms remote applications and other places requiring relatively low power. The generating capacity is up to 2kW. Small scale wind machines lower your electricity bills by 50% – 90%.
2. Which type of wind machines are used at several residence or local use?
a) Large size machines
b) Remote machines
c) Small size machines
d) Medium size machines
Explanation: These wind turbines may be used to supply less than 100 kW rated capacity, to several residences or local use. These do not require much space they can be installed on roof tops or on some high elevated areas.
3. Which type of wind turbines produce 100 kW or greater?
a) Large machines
b) Small machines
c) Medium machines
d) Remote Machines
Explanation: Large wind turbines are those of 100 kW rated capacity or greater. They are used to generate power for distribution in central power grids. They can have single generator at a single site or multiple generators sited at several places over an area.
4. Which part of the wind mill acts as a housing for the turbine?
a) Wind Vane
c) Wind mill head
Explanation: The wind mill head supports the rotor, housing, and rotor bearings. It also has control mechanism like changing the pitch of the blades for safety devices, tail vane to orient the rotor to face the wind. Its body is the size of the mini bus.
5. A rotor installed in a fixed orientation with the swept area perpendicular to the pre dominate wind direction is called ______
b) Yaw fixed machines
Explanation: In the locations with the prevailing wind in one direction, the design of a turbine can be greatly simplified. The rotor can be installed in a fixed orientation with the swept area perpendicular to the pre dominate wind direction. This machine is called yaw fixed.
6. How is the action of yaw controlled in small turbines?
a) Tail vane
d) Yaw motor
Explanation: In small turbines, yaw action is controlled by a tail vane while is larger machines a servomechanism operated by a wind-direction sensor controls the yaw motor keeping the turbine properly oriented.
7. Which part of the wind turbines senses wind speed, wind direction, shaft speed and torque?
a) Turbine blade
Explanation: The controller senses wind speed, wind direction, shafts speeds and torques, output power and generator temperature, Control signals are generated with the electrical output corresponding to the wind energy input.
8. Which type of wind turbine has low RPM?
a) Small wind turbine
b) Large wind turbine
c) Medium wind turbine
d) Remote wind turbine
Explanation: The rate of rotation of large wind turbine generators operating at rated capacity or below is controlled by varying the pitch of the rotor blades. It has low rpm, about 40 to 50. It is necessary to increase greatly the low rotor rate of turning using transmission mechanism.
9. Why recommendation of fixed ratio gears done for top mounted equipment?
a) Because they are easy install
b) Requires less space
c) Due to its low cost
d) Because of their high efficiency
Explanation: Fixed ratio gears are recommended for top mounted equipment because of their high efficiency, and minimum system risk. For bottom mounted equipment requiring a right angle drive transmission costs can be reduced on the hub by increasing rotor speed to generator.
10. Which type of generator are made use in wind turbines?
a) Recreational generators
b) Synchronous generator
c) Asynchronous generator
Explanation: Generators may be either constant or variable speed type. Variable speed units are expensive and/or unproved. Constant speed generator in use are synchronous induction and permanent magnet types. Synchronous unit is used for large aero generator systems. It is very versatile and has an extensive data base.
11. In which part do we find sensors and actuators?
a) Fixed gears
c) Control systems
Explanation: Control systems involves sensors and actuators. The modern large wind turbine generator requires a versatile and reliable control system. A control system is used for 1) changing the orientation of the rotor into the wind. 2) Start up and cut-in of the equipment. 3) Power control of the rotor by varying the pitch of the blades.
12. How many types of supporting tower for wind mill are generally used?
Explanation: Four types of generating tower are used generally:
1) The reinforced concrete tower
2) The pole tower
3) The built up shell tube tower
4) The truss tower.
13. On what does the selection of supporting structure depends?
a) Length of blades
b) Rotating capacity
c) Capacity of generator
d) Transmission systems
Explanation: The type of the supporting structure and its height is related to cost and the transmission system incorporated. Horizontal axis wind turbines are mounted on towers so as to be above the level of turbulence and other ground related effects.
14. At what type of location vibrations are more in the wind turbine?
a) Downwind location
b) Up wind location
Explanation: In the upwind location (i.e. the wind encounters the turbine before reaching the tower), the wake of the passing rotor blades causes repeated changes in the wind forces on the wind forces on the tower. Due to this the tower may vibrate and may eventually be damaged.
15. At what type of location vibrations are less in the wind turbines?
c) Downwind location
d) Upwind Location
Explanation: If the turbine is downwind from the tower, vibrations are less but the blades are subjected to severe alternating forces as they pass through the tower wake. Downwind rotors are generally preferred for large aero generators.
Sanfoundry Global Education & Learning Series – Energy Engineering.
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