Title: Module 4 Test, Part 2
Course: WIND 100WH Introduction to Wind Energy > Section: WIND 100WH Introduction to Wind Energy

Q: The device that changes the rpm of the low-speed shaft to a higher rpm is called a __________ .
- transmission
- differential
- transformer
- gearbox
A: gearbox

Q: A gearbox is required in a wind turbine to ___________________.
- increase the rotational speed for the generator
- change the power from low to high
- both of the above
- none of the above
A: increase the rotational speed for the generator

Q: Gearboxes must be well-built to ____________.
- prevent friction
- be used continuously
- prevent vibrations
- all of the above
A: all of the above

Q: What makes the gear ratio in a gearbox?
- The size of the gears
- The overall ratio of teeth for all gears
- The size of the shafts that turn the gears
- The shape of the gears
A: The overall ratio of teeth for all gears

Q: Gearbox ratios need to be well understood as they indicate the change in ___________ and _______ from its input shaft to its output shaft.
- drive / power
- ratio / power
- rpm / torque
- speed / velocity
A: rpm / torque

Q: A gear with straight teeth is called a _______________.
- bevel gear
- helical gear
- spur gear
- linear gear
A: spur gear

Q: The type of gear that allows for axial and radial forces is called a __________________ and is often quieter in operation.
- bevel gear
- high torque gear
- helical gear
- transom gear
A: helical gear

Q: What type of gears are is used in adjusting the yaw of large wind turbines?
- Helical gears
- Herringbone gear with rack
- Spur ring gear and spur gear/s
- Spider gears and shaft
A: Spur ring gear and spur gear/s

Q: A large advantage with a worm-type drive is that they have more gear surface area, making them __________.
- easier to move
- quieter to use
- easier to program
- stronger
- easier to move and quieter to use
A: easier to move and quieter to use

Q: A large wind turbine’s gearbox is designed to withstand extremely strong and changing wind speeds and would likely use __________.
- helical planetary gears
- bevel planetary gears
- spur planetary gears
- double herringbone gears
A: helical planetary gears

Q: Most drive trains are mounted to what part of the wind turbine?
- The main shaft
- The gear box assembly
- The bedplate
- The chassis bar
A: The bedplate

Q: A gearbox is used to change the rotational speed (in rpm) to a higher or lower rotational speed.
- True
- False
A: True

Q: Torque and velocity together are what “powers” a gearbox’s input shaft. For a reduction-type gearbox, ________ is decreased and torque is __________ at the output shaft.
- velocity, increased
- torque, increased
- velocity, decreased
- torque, decreased
A: velocity, increased

Q: If a gearbox has a gear ratio of 3.6:17 it is a reduction-type gearbox.
- True
- False
A: False

Q: If a gearbox with a gear ratio of 15:4 has its driven shaft (input shaft) coupled to a shaft running at 300 rpm, its output speed would be 4/15 of 300, which is equal to ________________.
- 300 rpm
- 40 rpm
- 88 rpm
- 80 rpm
A: 80 rpm

Q: An ideal gearbox has no internal friction and therefore would be 100% efficient. However, this is not ever the case, as gearboxes have internal losses due to friction and heat. When solving equations for power output, this must be considered as a type of _____________.
- coefficient
- value
- counter measure
- efficiency gain
A: coefficient

Q: Gearboxes have a rated torque for the input and outputs shafts, and also an overall power rating, (usually in Horsepower in the U.S.)
- True
- False
A: True

Q: If a gearbox’s input shaft is to endure 30 foot-pounds of torque at 500 rpm what should its minimum Horsepower be?
- 0.5
- 3
- 1.5
- 2.25
A: 3

Q: The space between gear teeth is called _______________ and it must be compensated for to prevent control loops from interpreting it as a position problem. It increases as the gears wear.
- backlash
- counter lash
- countersink
- tooth distance
A: backlash

Q: An ordinary bearing may be as simple as a bushing, which are simple devices made of special metals, separated from the other surfaces usually by a lubricant.
- True
- False
A: True

Q: The journal of a bearing is the part that supports the bearing.
- True
- False
A: True

Q: The axis is the observed line about which the bearing and components rotate.
- True
- False
A: True

Q: The __________ force is the forces acing on the bearing surfaces.
- radial
- concentric
- net
- backlash
A: radial

Q: A ______________ utilizes hardened steel balls contained by an inner and out race. The two surfaces roll the balls and friction between the inner surfaces of each is decreased. They are often sealed with grease.
- shaft bushing
- ball bearing
- simple bearing
- plain bearing
A: ball bearing

Q: ___________________ act as greasing points for the bearing. They provide an attachment point for grease gun nozzle to attach to. A grease gun forces grease in through the ____________________’s check valve, thus re-lubricating components.
- Grease-sert (grease insert)
- Grease bypass
- Grease spot
- Lubrication inspection glass
A: Grease-sert (grease insert)

Q: __________ can handle more shock and are less susceptible to damage caused by quick increases in torque.
- Roller bearings
- Bushings
- Slips
- Ball bearings
A: Roller bearings

Q: A ___________ roller bearing has two separate roller rows on the single race; they are designed to withstand more weight than a regular roller bearing.
- double-row
- tapered type
- dual-acting
- double faced
A: double-row

Q: A tapered roller bearing is built at a small angle to prevent friction from axial, but not radial forces.
- True
- False
A: False

Q: A _____ is similar to a tapered roller bearing, but has a greater taper angle. They’re designed to absorb thrust loads pushing against it. A very large_____ is what larger nacelles rest upon and is called the yaw bearing.
- thrust bearing
- plain bearing
- planar bearing
- axial roller
A: thrust bearing

Q: Bearings are often housed in pillow blocks, cassettes, and are sometimes pressed into position.
- True
- False
A: True

Q: A bearing puller is required to remove pressed in or seized bearings.
- True
- False
A: True

Q: A hand press, such as an arbor press, is used to push smaller bearings into their housings.
- True
- False
A: True

Q: A helical gear is a gear that overcomes fatiguing forces, mainly axial thrust, by having its teeth straight rather than diagonal.
- True
- False
A: False

Q: The image above is a _______________________.
- roller bearing
- ball bearing
- tube roller
- barrel bearing
A: roller bearing

Q: The image above is a ______________________.
- tapered plain bearing
- helical bearing
- ball bearing
- needle bearing
- none of the above
A: none of the above

Q: The bearing above should be used for ______________________________________.
- absorbing axial and radial forces, such as a wheel
- absorbing radial forces, such as a propeller or turbine shaft
- absorbing great axial forces, such as a heavily weighted spindle
- none of the above
A: absorbing axial and radial forces, such as a wheel

Q: The bearing above would be ideal for very heavy, often static loads.
- True
- False
A: False

Q: The most basic gear having straight teeth is called a ___________.
- plain gear
- bevel gear
- spur gear
- sprocket
A: spur gear

Q: To change an oscillating (back and forth) linear motion into an oscillating rotational motion a spur and rack gear would be used.
- True
- False
A: True

Q: The face of a gear is the surface of the gear that interacts with another gear.
- True
- False
A: True

Q: A worm gear could be used to change high-speed, low-torque rotation into low-speed, high-torque rotation. This would be a type of reduction gearbox.
- True
- False
A: True

Q: A worm gear should ____________ be used to change low-speed, high-torque rotation into high-speed, high-torque rotation.
- always
- sometimes
- never
- only
A: never

Q: Planetary gears are used for speed/torque conversion. Planetary gearboxes are a part of a large wind turbine’s various motor-drive systems (yaw and pitch) and also the larger rotor gearbox.
- True
- False
A: True

Q: Since planetary gears use many gears, they have a much needed high gear ratio and also create less stress on their individual gears, however they have a great need for maintenance.
- True
- False
A: True

Q: There would be a clearance of _____________ between gears with a center-to-center distance of 90.1cm. Given gear one has a root diameter of 80cm and gear two has a root diameter of 100cm.
- 1/16 inches
- 2mm
- 10mm
- 1mm
A: 10mm

Q: A simple gearbox has an input gear with 25 teeth, which drives an output gear with 125 teeth.
What is the overall gear ratio?
What is the speed (in rpm) of the output shaft, if the input shaft is turning at 300 rpm?
The gearbox must be rated near __________ Horsepower if the output shaft is to turn with 60 ft-lbs of torque.
- 5:1, 50, ½ H.P.
- 5:1, 1/3, 0.2 H.P.
- 5:1, 60, 100 H.P.
- 1:5, 1/8, 20 H.P.
- none of the above
A: 5:1, 50, ½ H.P.

Q: Gear backlash can be measured using a feeler gauge.
- True
- False
A: True

Q: The clearance of a gear is the distance between __________.
- gear two’s base and the other gear’s tooth surface
- gear one’s base and the other gear’s tooth surface
- the center-to-center distance minus the sum of the root radii for each gear
- all of the above
A: all of the above

Q: The image at left is a ___________ -type gear, the one at the right is a ___________-type gear.
- bevel, plain
- helical, plain
- helical, spur
- bevel, straight
A: helical, spur

Q: The image above is a ____________-type gear
- bevel
- helical
- worm
- planetary
A: bevel