No. 0072 Basic hydraulics

Q1: Pascal’s law says:
A: Force = pressure x area

Q2: Which statement is true?
A: Hydraulic components have a high power to weight ratio.

Q3: What creates pressure in a hydraulic system?
A: The resistance to flow

Q4: This is a:
A: 4 port, 3 position float centre directional control valve

Q5: This is a:
A: Variable delivery, bi directional pump

Q6: This is a:
A: Relief valve

Q7: What is the most common reason for failures in hydraulic systems?
A: Contamination of the oil

Q8: Which type of pump is most common in hydraulic systems?
A: Positive displacement pump

Q9: Is hydraulic oil compressible?
A: Approx. 1/2% pr. 7 MPa

Q10: When do we use a pilot operated check valve?
A: To prevent creeping

Q11: Counterbalance valve is used:
A: To support a load and prevent “creeping”

Q12: What type of gas should be used to charge an accumulator?
A: Nitrogen

Q13: Internal leaks create:
A: Heat

Q14: Energy not used to move the load in a hydraulic system turns into what?
A: Heat

Q15: What is the most reliable indication of a faulty hydraulic pump?
A: Excessive case drain flow

Additional questions:

Q: What statement is not true?
A: Hydraulics produce constant torque with variable speed