EVT EVT Hydraulic Systems & Aerial Apparatus

Question 1

What is the primary function of a hydraulic relief valve in an aerial apparatus system?

Accepted Answer

To prevent system overpressure by diverting excess fluid

Answer

To increase pump pressure

Answer

To filter hydraulic fluid contaminants

Answer

To measure fluid viscosity

Question 2

Which type of hydraulic pump is most commonly used in aerial ladder apparatus due to its ability to deliver constant flow?

Accepted Answer

Piston pump

Answer

Gear pump

Answer

Vane pump

Answer

Centrifugal pump

Question 3

According to NFPA 1901, aerial devices must be tested at what percentage above their rated working load?

Accepted Answer

150%

Answer

100%

Answer

125%

Answer

200%

Question 4

What condition is indicated when a hydraulic cylinder drifts under load with no control input?

Accepted Answer

Internal cylinder seal leakage

Answer

Normal thermal expansion

Answer

Low hydraulic fluid temperature

Answer

Excessive pump speed

Question 5

What is the purpose of a hydraulic accumulator on an aerial apparatus?

Accepted Answer

Store pressurized fluid for emergency operations

Answer

Filter hydraulic fluid

Answer

Cool hydraulic fluid

Answer

Increase pump displacement

Question 6

What does a high hydraulic fluid temperature typically indicate during aerial apparatus operation?

Accepted Answer

Excessive load cycles or restricted flow

Answer

Proper system function

Answer

Correct fluid viscosity

Answer

New pump break-in period