WTT Hydraulic & Lubrication Systems 3

Question 1

What is the function of a pressure relief valve in a hydraulic circuit?

Accepted Answer

To protect the system from overpressure by diverting excess fluid to tank

Answer

A pressure relief valve opens when system pressure exceeds a set limit, diverting fluid to tank to prevent component damage.

Question 2

A gearbox oil sample analysis shows elevated iron (Fe) and copper (Cu) particles. What does this most likely indicate?

Accepted Answer

Wear in steel gear surfaces and bronze bushings or thrust washers

Answer

Elevated iron indicates steel gear or bearing wear, while copper particles point to bronze bushing or thrust washer degradation.

Question 3

What is the recommended method for transferring lubricating oil into a wind turbine gearbox to minimize contamination?

Accepted Answer

Use a dedicated transfer pump with a 10-micron or finer filter

Answer

Using a dedicated transfer pump with fine filtration prevents particulate contamination that can accelerate gear and bearing wear.

Question 4

Which parameter is most critical when selecting grease for wind turbine pitch and yaw bearing lubrication?

Accepted Answer

NLGI grade and base oil viscosity appropriate for low temperature and high load

Answer

NLGI grade and base oil viscosity determine pumpability at low temperatures and film strength under the high loads of pitch and yaw bearings.

Question 5

What is the purpose of a hydraulic flow divider in a multi-actuator pitch system?

Accepted Answer

To ensure equal flow to each pitch cylinder for synchronized blade movement

Answer

A flow divider splits hydraulic flow equally among multiple cylinders, ensuring all three blades pitch simultaneously and uniformly.

(WTT) Wind Turbine Technician Certification Practice Test