WTT Mechanical Systems & Drivetrain 3

Question 1

Which main bearing configuration uses two rows of rollers arranged in a tapered pattern to handle both radial and axial loads on a wind turbine rotor?

Accepted Answer

Double-row tapered roller bearing

Answer

Double-row tapered roller bearings can carry combined radial and bidirectional axial (thrust) loads, making them suitable for wind turbine main shafts.

Question 2

What does 'preload' mean in the context of wind turbine main shaft bearings?

Accepted Answer

A deliberately applied axial force that removes internal clearance from the bearing

Answer

Bearing preload is an intentional compressive force that eliminates internal clearance, improving stiffness, reducing vibration, and extending fatigue life.

Question 3

A wind turbine technician notices metallic particles in the gearbox oil sample that are silvery flakes larger than 50 µm. What does this most likely indicate?

Accepted Answer

Fatigue spalling of gear tooth surfaces or bearing raceways

Answer

Large silvery flakes are characteristic of fatigue spalling, where surface material breaks away from gear teeth or bearing raceways under cyclic stress.

Question 4

What is the purpose of an oil cooler in a wind turbine gearbox lubrication system?

Accepted Answer

Maintain oil within its optimal viscosity and temperature operating range

Answer

An oil cooler dissipates heat generated by gear meshing and bearing friction, keeping oil temperature within the range where viscosity provides adequate film thickness.

Question 5

Which component transfers rotor torque from the low-speed shaft to the gearbox in a direct-drive or semi-direct-drive wind turbine that uses a torque tube?

Accepted Answer

Shrink disc locking assembly

Answer

A shrink disc (also called a locking disc) creates a high-friction interference fit between the main shaft and the gearbox input shaft without requiring keyways.

(WTT) Wind Turbine Technician Certification Practice Test

(WTT) Wind Turbine Technician Certification Practice Test

WTT Mechanical Systems & Drivetrain 3