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Wind Energy Engineering

Instructions:

Answer 10 questions in 15 minutes.
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Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. What is the main difference between the gearbox in a wind turbine and one in any other machine?
Epicyclic gear.
Normally gearboxes reduce speed (and sometimes are called speed reducers). In a wind turbine - they increase the speed
Three.
No; worm gears only reduce the angular speed.

2. What is the main role of a gearbox in a wind turbine?
Epicyclic gear.
The torque on the rotor shaft is larger (because its speed is less)
It increases the angular speed of the rotor shaft to an appropriate value for the generator
In a spur gear - the teeth are parallel to the gear shaft. In helical gears - they are at an angle (this shows clearly when one looks at a gear at a direction perpendicular to the shaft direction).

3. How many planets are usually in a planetary gear?
The gear ratio is the ratio of the number of teeth between two mating gears; it is usually the output to the input ratio - for example - 1 to 5 - meaning that the output gear has 5 times more teeth than the input gear.
Epicyclic gear.
Three.
No; worm gears only reduce the angular speed.

4. Can a worm gear be used in a wind turbine?
The torque on the rotor shaft is larger (because its speed is less)
The gear ratio is the ratio of the number of teeth between two mating gears; it is usually the output to the input ratio - for example - 1 to 5 - meaning that the output gear has 5 times more teeth than the input gear.
It increases the angular speed of the rotor shaft to an appropriate value for the generator
No; worm gears only reduce the angular speed.

5. What is the other name for a planetary gear?
In a spur gear - the teeth are parallel to the gear shaft. In helical gears - they are at an angle (this shows clearly when one looks at a gear at a direction perpendicular to the shaft direction).
Epicyclic gear.
Normally gearboxes reduce speed (and sometimes are called speed reducers). In a wind turbine - they increase the speed
It has more than one input and one output. Its size for the same power is smaller than the other gears. The input and output shafts are aligned.

6. What is the gear ratio?
The gear ratio is the ratio of the number of teeth between two mating gears; it is usually the output to the input ratio - for example - 1 to 5 - meaning that the output gear has 5 times more teeth than the input gear.
No
Epicyclic gear.
The torque on the rotor shaft is larger (because its speed is less)

7. What is the difference between a spur gear and a helical gear?
In a spur gear - the teeth are parallel to the gear shaft. In helical gears - they are at an angle (this shows clearly when one looks at a gear at a direction perpendicular to the shaft direction).
The torque on the rotor shaft is larger (because its speed is less)
Three.
It increases the angular speed of the rotor shaft to an appropriate value for the generator

8. Do all the gears have the same gear geometry?
Epicyclic gear.
It increases the angular speed of the rotor shaft to an appropriate value for the generator
No
It has more than one input and one output. Its size for the same power is smaller than the other gears. The input and output shafts are aligned.

9. What is the advantage of a planetary gear?
Normally gearboxes reduce speed (and sometimes are called speed reducers). In a wind turbine - they increase the speed
The gear ratio is the ratio of the number of teeth between two mating gears; it is usually the output to the input ratio - for example - 1 to 5 - meaning that the output gear has 5 times more teeth than the input gear.
Epicyclic gear.
It has more than one input and one output. Its size for the same power is smaller than the other gears. The input and output shafts are aligned.

10. In a gearbox of a wind turbine - which is larger: the torque on the rotor shaft or the torque on the generator shaft?
The gear ratio is the ratio of the number of teeth between two mating gears; it is usually the output to the input ratio - for example - 1 to 5 - meaning that the output gear has 5 times more teeth than the input gear.
It increases the angular speed of the rotor shaft to an appropriate value for the generator
The torque on the rotor shaft is larger (because its speed is less)
Normally gearboxes reduce speed (and sometimes are called speed reducers). In a wind turbine - they increase the speed