Wind Energy System
1.When did the development of wind power in India began?
A.1965
B.1954
C.1990
D.1985
Answer: 1990
2.At what range of speed is the electricity from the wind turbine is generated?
A.100 – 125 mph
B.450 – 650 mph
C.250 – 450 mph
D.30-35 mph
Answer: 30-35 mph
3.What is the diameter of wind turbine blades?
A.320 feet
B.220 feet
C.80 feet
D.500 feet
Answer: 220 feet
4.What are used to turn wind energy into electrical energy?
A.Turbine
B.Generators
C.Yaw motor
D.Blades
Answer: Turbine
5.What type of energy is wind energy?
A.Renewable energy
B.Non-renewable energy
C.Conventional energy
D.Commercial energy
Answer: Renewable energy
6.What happens when the land near the earth’s equator is heated?
A.All the oceans gets heated up
B.Small wind currents are forme d
C.Rise in tides
D.Large atmospheric winds are created
Answer: Large atmospheric winds are created
7.Which country created wind mills?
A.Egypt
B.Mongolia
C.Iran
D.Japan
Answer: Iran
8.What is the main source for the formation of wind?
A.Uneven land
B.Sun
C.Vegetation
D.Seasons
Answer: Sun
9.How much wind power does India hold?
A.20,000 MW
B.12,000 MW
C.140,000 MW
D.5000 MW
Answer: 20,000 MW
10.What does Heating and cooling of the atmosphere generates?
A.Thermo line circulation
B.Radiation currents
C.Convection current
D.Conduction current
Answer: Convection currents
11.The amount of energy available in the wind at any instant is proportional to of the wind speed.
A.Square root power of two
B.Square root power ofthree
C.Square power
D.Cube power
Answer:Cube power
12.Wind energy is harnessed as energy with the help of windmill or turbine.
A. Mechanical
B. Solar
C. Electrical
D. Heat
Answer: Mechanical
13.Winds having following speed are suitable to operate wind turbines.
A.5–25m/s
B.10–35m/s
C.20 – 45m/s
D.30 – 55m/s
Answer: 5 – 25 m/s
14.The following is (are) the classification of winds
A. Global wind
B. Local wind
C. Both (A) and (B)
D. None of the above
Answer: Both (A) and (B)
15.Global Cold wind move from
A. Polar to equatorial region
B. Equatorial to polar region
C. Equatorial to oceanic region
D. Oceanic to Equatorial region
Answer: Polar to equatorial region
16.Force is responsible for forcing the global winds towards westernly direction.
A.Coriolis
B.Gravitational
C.Centripetal
D.Centrifugal
Answer: Coriolis
17.Global winds towards westernly direction are known as
A.Trade winds
B Western winds
C.Eastern winds
D.None of the above
Answer: Trade winds
18.Uneven heating occurs on land surface and water bodies are due to
A.Air Currents
B.Solar radiation
C.Lunar eclipse
D.None of the above
Answer: Solar radiation
19.The following factor(s) affects the distribution of wind energy
A.Mountain chains
B.The hills, trees and buildings
C.Frictional effect of the surface
D. All of the above
Answer: All of the above
20.The wind intensity can be described by
A.Reynolds number
B.Mach number
C.Beaufort number
D.Froude number
Answer: Beaufort number
21.How much power does the small scale wind machine generate?
a)18 KW
b)2 KW
c)12 KW
d)30 KW
Answer: b
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%.
22.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
Answer: d
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.
23.Which type of wind turbines produce 100 kW or greater?
a)Large machines
b)Small machines
c)Medium machines
d)Remote Machines
Answer: a
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.
24.Which part of the wind mill acts as a housing for the turbine?
a)Wind Vane
b)Shaft
c)Wind mill head
d)Turbine
Answer: c
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.
25.A rotor installed in a fixed orientation with the swept area perpendicular to the pre dominate wind direction is called _
a)Nacelle
b)Yaw fixed machines
c)Blades
d)Anemometer
Answer: b
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.
26.How is the action of yaw controlled in small turbines?
a)Tail vane
b)Blades
c)Shaft
d)Yaw motor
Answer: a
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.
27.Which part of the wind turbines senses wind speed, wind direction, shaft speed and torque?
a)Turbine blade
b)Shaft
c)Rotor
d)Controller
Answer: d
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.
28.Which type of wind turbine has low RPM?
a)Small wind turbine
b)Large wind turbine
c)Medium wind turbine
d)Remote wind turbine
Answer: b
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.
29.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
Answer: d
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.
30.Which type of generator are made use in wind turbines?
a)Recreational generators
b)Synchronous generator
c)Asynchronous generator
d)Alternator
Answer: b
Explanation: Generators may be either constant or variable speed type. Variable speed units are expensive and/or unproved. Constant speed generators 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.
31.In which part do we find sensors and actuators?
a)Fixed gears
b)Turbines
c)Control systems
d)Blades
Answer: c
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.
32.On what does the selection of supporting structure depends?
a)Length of blades
b)Rotating capacity
c)Capacity of generator
d)Transmission systems
Answer: d
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.
33.At what type of location vibrations are more in the wind turbine?
a)Downwind location
b)Up wind location
c)Windward
d)Leeward
Answer: b
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.
34.At what type of location vibrations are less in the wind turbines?
a)Windward
b)Leeward
c)Downwind location
d)Upwind Location
Answer: c
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.
35.When was the Halladay wind mill introduced?
a)1920
b)1923
c)1854
d)1864
Answer:c
Explanation: Invented by Daniel Halladay in 1854, the Halladay Standard was the first commercially successful self-governing windmill in 1854 was the firms of Halladay, McCray & Co., Ellington, Conn. Partners in the company were inventor Daniel Halladay, John Burnham and Henry McCray.
36.What is the inherent weakness of all wind machines?
a)Their efficiencies
b)Requires powerful winds to make fan rotate
c)Their dependency on the wind speed
d)Cannot be easily repaired
Answer: c
Explanation: An inherent weakness of all wind machines are the strong dependence of the power produced on wheel diameter and wind speed, being proportional to turbine wheel area, i.e. to the square of its diameter and to the cube of wind velocity.
37.Why severe fluctuations in power are always undesirable in windmill?
a)Because they pose power oscillations problems
b)Damage of parts due to fluctuations
c)The efficiency of the plant will be reduced
d)Results in damage to the whole plant
Answer: a
Explanation: Severe fluctuations in power are always undesirable, because they pose power oscillation problems on the grid and severe strains on the windmill hardware. From an economic point of view, a windmill is designed to produce a rated power output corresponding to maximum, or near maximum, prevailing wind velocity at a given site would generate low powers, with full capacity of the turbine and electric generator unused much of time.
38.How many of windmills are there?
a)2
b)3
c)4
d)5
Answer: a
Explanation: There are two classes of windmill, horizontal axis and vertical axis. The vertical axis design was popular during the early development of the windmill. However, its inefficiency of operation let to the development of numerous horizontal axis designs.
39.Name the windmill which has four blades mounted on a central post.
a)Post mill
b)Smock mill
c)Tower mill
d)Fan mill
Answer: a
Explanation: The post mill has blades mounted on a central post. The horizontal shaft of the blade is connected to a large break wheel. The break wheel interacts with a gear system, called the wallower, which rotates a central, vertical shaft. This motion can then be used to power water pumping or grain grinding activities.
40.Name the type of windmill which consists of a sloping, horizontally weather boarded or thatched tower.
a)Post mill
b)Smock mill
c)Tower mill
d)Fan mill
Answer: b
Explanation: The smock mill is a type of windmill that consists of a sloping, horizontally weather boarded or thatched tower, usually with six or eight sides. It is topped with a roof or cap that rotates to bring the sails into the wind. It is similar to post mill. It is named so because of its appearance.
41.Which are further improvements on smock mill?
a)Post mill
b)Smock mill
c)Tower mill
d)Fan mill
Answer: c
Explanation: Tower mills are further improvements on smock mills. They have a rotating cap and permanent body, but this body is made of brick or stone. This fact makes it possible for the towers to be rounded. A round structure of it allows for large and taller towers.
42.Which type of windmills are been used for primary purposes?
a)Post mill
b)Smock mill
c)Tower mill
d)Fan mill
Answer: d
Explanation: The fan type windmill is specifically made for individuals. It is much smaller and used primarily for pumping water. It consists of a fixed tower (mast), a wheel and tail assembly (fan), a head assembly, and a pump.
43.In which of the following, does machine rotor drives through a step up gear box?
a)Horizontal axis with two aerodynamic blades
b)Horizontal axis propeller type wind mill
c)Horizontal axis multi bladed type wind mill
d)Sail type wind mill
Answer: a
Explanation: In horizontal axis with two aerodynamic type windmill the machine rotor drives through a step up gear box. The blade rotor is designed to orient downwind of the tower. The components are mounted on bed plate which is attached on a pintle at the top of the tower.
44.The rotor blades are continuously flexed by unsteady aerodynamic gravitational and inertia loads?
a)True
b)False
Answer: a
Explanation: The rotor blades are continuously flexed by unsteady aerodynamic gravitational and inertia loads, when the machine is in operation. If the blades are made using metal, flexing reduces their fatigue life.
45.Which type of the following consists of single blade?
a)Horizontal axis with two aerodynamic blades
b)Horizontal axis propeller type wind mill
c)Horizontal axis multi bladed type wind mill
d)Sail type wind mill
Answer: b
Explanation: Horizontal axis propeller type wind mill consists of a long blade mounted on a rigid hub, induction generator and gear box. If extremely long blades are mounted on rigid hub, large blade root bending moments occur due to tower shadow, gravity and sudden shifts in wind directions.
46.Which windmill blades are made by an array of wooden slats?
1. In which of the following, does machine rotor drives through a step up gear box?
a)Horizontal axis with two aerodynamic blades
b)Horizontal axis propeller type wind mill
c)Horizontal axis multi bladed type wind mill
d)Horizontal axis wind mill Dutch type
Answer: d
Explanation: Dutch type wind mill is one of the oldest wind mills in designs. The blade surfaces are made from an array of wooden slats which rotates at high wind speeds. These types of wind mill are cheap to build since the wood is made use of to build.
47. Which type of windmill blades are made out of sheet metal or aluminum?
1. In which of the following, does machine rotor drives through a step up gear box?
a)Horizontal axis with two aerodynamic blades
b)Horizontal axis propeller type wind mill
c)Horizontal axis multi bladed type wind mill
d)Sail type wind mill
Answer: c
Explanation: Horizontal axis multi blade windmill is made from sheet metal or aluminum. The rotors have high strength to weight ratios. They have good power coefficient, high starting torque and added advantages of simplicity and low cost.
48. Which type of wind mills blade are made out of cloth?
1. In which of the following, does machine rotor drives through a step up gear box?
a)Horizontal axis with two aerodynamic blades
b)Horizontal axis propeller type wind mill
c)Horizontal axis multi bladed type wind mill
d)Sail type wind mill
Answer: d
Explanation: The blade surface of sail type wind mill is made of cloth, nylon or plastics arranged as mast and pole or sail wings. There is also variation in the number of sails used. Sails are found in different designs, from primitive common sails to the advances patent sails.
49.Which type of windmill has better performance?
a)Vertical type wind mills
b)Darrieus type machines
c)Magnus effect rotor
d)Horizontal type windmills
Answer: d
Explanation: The horizontal axis mills generally have netter performance. They have been used for various applications including electric power generation, and pumping water. The latter introduces some complexity into the design as the mechanical energy has to be transmitted over a distance.
50.With upto how many propellers can windmills are built?
a)4
b)2
c)7
d)6
Answer: d
Explanation: Wind turbines have been built with upto six propellers type blades but two and three bladed propellers are most common. A one bladed rotor with a balancing counter weight has some advantages, including lower weight and cost and simpler controls, over the multi- bladed type.
51.Turbines with how many propellers are used in order to avoid vibrations?
a)1
b)2
c)3
d)4
Answer: c
Explanation: Turbines with three blades are used to avoid vibrations that occur due to the turning or yawing of the rotor in order to face in into the wind. However, this problem can be overcome by controlling the yaw rate.
52.What type of cross sections does wind turbine blades have?
a)Penta hedral cross section
b)Air foiled type cross section
c)Radar cross section
d)Turbo cross section
Answer: b
Explanation: Wind turbine blades have an air foiled type of cross section and a variable pitch. They are slightly twisted from the outer tip to the root in order to reduce the tendency for the rotor to stall. The blades can also have constant chord length.
53.What does WECS stands for?
a)Wind energy conversion system
b)Wind engine control system
c)Wind energy combined system
d)Wind engine comparison system
Answer: a
Explanation: A wind energy conversion system (WECS), or wind energy harvester is a machine that, powered by the energy of the wind, generates mechanical energy that can be used to directly power machinery or to power an electrical generator for making electricity.
54.Aero turbine is the fraction of power in the wind through the swept area which is converted into useful mechanical shaft power is called
a)Coefficient of performance
b)Coefficient of variation
c)Coefficient of lift
d)Coefficient of spin
Answer: a
Explanation: The coefficient of performance of an aero turbine is the fraction of power in the wind through the swept area which is converted into useful mechanical shaft power. Cp for horizontal axis wind machine has theoretical maximum value = 0.593.
55.Which type of vertical wind machine consists of spinning cylinders?
a)Cup anemometer
b)Savonius rotor
c)Darrieus type rotor
d)Magnus effect rotor
Answer: d
Explanation: Magnus effect rotor concept was first demonstrated by Magnus in 1912. It consists of spinning cylinders. When cylinders spun in wind stream, translational forces are produced perpendicular to the wind stream by the Magnus effect. Such a device can be used to propel ships or land vehicles.
56.Which type of vertical wind machine has relatively low solidity and low starting torques?
a)Cup anemometer
b)Savonius rotor
c)Darrieus type rotor
d)Magnus effect rotor
Answer: c
Explanation: Darrieus type rotors are lift devices characterized by curved blades with air foil cross sections. They have relatively low solidity and low starting torques, but high tip to wind speeds and therefore relatively high power outputs per given rotor weight and cost.
57.What form of force acts on the blades of Darrieus machine?
a)Pure tension
b)Compression
c)Shear force
d)Air resistance force
Answer: a
Explanation: Darrieus wind mill has two or three thin, curved blades with airfoil cross section and constant chord length. Both ends of blades are attached to a vertical shaft. Thus the force in the blade due to rotation is pure tension.
58.When was the Darrieus type machine invented?
a)1925
b)1932
c)1929
d)1948
Answer: a
Explanation: Darrieus type machine was invented originally and patented in 1925 by G.J.M> Darrieus, a French engineer. The Darrieus wind mill is a vertical axis machine that has the same advantage of a modern rapidly rotating propeller type windmill, by use of an efficient airfoil, effectively intercepts large area of wind with a small blade area.
59.Why is Savonius rotor not suitable for installation?
a)Because of long drive shaft
b)Because of its low capacity motor
c)Because of its typical blade design
d)Due to the light material it is made of
Answer: a
Explanation: Savonius rotor is not useful for very high installation because of long drive shaft problems. Bracing of the topmost bearing above the rotor of a very tall vertical axis machine is difficult requiring very long guy wires.
60.Which type of axis does a Savonius Rotor has?
a)Horizontal axis
b)Mediolateral axis
c)Vertical axis
d)Lateral Axis
Answer: c
Explanation: A Savonius wind energy conversion system has a vertical axis and hence eliminates the expensive power transmission system from the rotor to the axis. Since it is a vertical axis machine it does not matter much about the wind direction.
61.Which of the following type of turbine or the rotor requires relatively low velocity winds for operation?
a)Cup anemometer
b)Savonius rotor
c)Darrieus type rotor
d)Magnus effect rotor
Answer: b
Explanation: Savonius rotor is a simple WEC system which woks like a cup anemometer. This type was invented by S.J. Savonius in the year 1920. It requires relatively low velocity winds for operation. It consists of two half cylinders facing opposite directions forming as S-shaped cross section.
62.What units does the anemometer measure in?
a)Feet per minute
b)Liters per minute
c)Centimeters per minute
d)Meter per seconds
Answer: a
Explanation: The anemometer measures in feet per minute, or FPM. The rotation is sensed by a magnetic or optical sensor that converts the signal to FPM measurement. An arrow on the vane head identifies the direction the airflow must travel through the vane to obtain proper measurements.
63.Which is the device that measures wind direction and its intensity?
a)Wind socks
b)Weather vane
c)Pin wheels
d)Anemometers
Answer: d
Explanation: An anemometer is any device that measures wind direction and intensity. It may be simple, such as the devices described above, or it may be a complex, computer-aided machine that measures and records wind patterns over time. More advanced anemometer machines are used to aid in professional weather reporting and air traffic control.
64.Which is the wind direction showing device that spins perpendicularly?
a)Wind socks
b)Weather vane
c)Pin wheels
d)Anemometers
Answer: c
Explanation: A pinwheel is a windmill-style turbine that spins perpendicularly to the wind affecting it. Like wind socks and weather vanes, a pinwheel can be attached to a rotating base. This allows the pinwheel to change direction with the wind, and it will spin facing into the oncoming wind.
65.A device which is used as device for showing direction wind as well used as a decorative purpose?
a)Wind socks
b)Weather vane
c)Pin wheels
d)Anemometers
Answer: b
Explanation: A weather vane works similarly to wind sock. Instead of a tubular sock, the weather vane is made by placing a horizontal pole at the top of vertical pole. The poles are joined together so that the horizontal pole has a flattened, vertical end that reacts to wind.
66.In which wind measuring device a tubular piece of thin flexible fabric hanged vertically to determine direction?
a)Wind socks
b)Weather vane
c)Pin wheels
d)Anemometers
Answer: a
Explanation: Wind sock is a very basic device that measure wind direction and provide a rough idea of the wind’s intensity. A wind sock is a tubular piece of fabric or thin, flexible fabric attached to a pole. When there is no wind, the fabric hangs vertically from the attached pole.
