250+ TOP MCQs on Fluid Power Systems – 2 and Answers

Mechatronics Interview Questions and Answers for Experienced people on “Fluid Power Systems – 2”.

1. Which type of mechanical device is used to give energy to the liquid?
a) Fluid power system
b) Hydraulic system
c) Pneumatic system
d) Hydraulic Pumps
Answer: d
Clarification: Pump is a mechanical device which gives energy to the liquid. The liquid can have energy in any of the forms such as Kinetic energy, Pressure energy and potential energy. The fluid Power system is a power transmission system in which, the transmission of power takes place by means of “oil under pressure” or “compressed air”. If “oil under pressure” is used in the system for power transmission then the system is called as hydraulic system. If “compressed air” is used in the system for power transmission then the system is called a Pneumatic system.

2. Which among the following pumps have a definite amount of discharge?
a) Positive displacement pumps
b) Non-positive displacement pumps
c) Self-priming pumps
d) Jet pumps
Answer: a
Clarification: In positive displacement pumps, the discharge is positive. The word positive implies that there will be a definite amount of discharge irrespective of an increase in pressure. In non-positive displacement pumps, the discharge is not constant. Self-priming pumps and Jet pumps are the types of non-displacement pumps.

3. Which among the following is not the component of FRL unit?
a) Air filter
b) Air dryer
c) Air regulator
d) Air lubricator
Answer: b
Clarification: The FRL unit does not consist of the air filter. It contains Air dryer, Air regulator and Air lubricator. The air filter removes the dust particles from compressed air and allows clean dry compressed air to the system. Air regulator controls the pressure of the compressed air and Air lubricator adds lubricating oil to the compressed air.

4. What is the function of the flow control valve?
a) Controls the direction of flow of air
b) The moisture is separated and removed
c) It converts the mechanical energy to hydraulic energy
d) It controls the rate of flow of compressed air
Answer: d
Clarification: The flow control valve controls the rate of flow of compressed air, by which speed of extension or retraction of the actuator is controlled. The direction control valve controls the direction of the flow of oil.

5. The direction control valve controls ____
a) direction of flow
b) rate of flow
c) moisture
d) force and motion
Answer: a
Clarification: It controls the direction of flow of compressed air, by which speed of extension or retraction of the actuator is controlled. The flow control valve controls the rate of flow of compressed air. This moisture is separated and removed by the air dryer. Force and motion are controlled through the double acting cylinder.

6. Which among the following is an advantage of the Pneumatic system?
a) The requirement of a lubricator
b) Runs continuously
c) Use of silencers
d) Low viscosity
Answer: b
Clarification: Pneumatic systems can run continuously for a longer period. Harder it runs, cooler it works. In any pneumatic system, the continuous free expansion of compressed air causes chilling effect and dues the continuous long run would not heat the system components. The other options mentioned are the disadvantages or limitations of the Pneumatic systems.

7. Which among the following is a disadvantage of Pneumatic system?
a) The requirement of a lubricator
b) Runs continuously
c) Used better in mines
d) Produces a dust-free surroundings
Answer: a
Clarification: A lubricator is required in a Pneumatic system to add lubricant oil to compressed air or to minimize friction which is considered as one of the disadvantage or limitation of the system. The other options mentioned are the advantages of the Pneumatic systems.

8. Which among the following are not the applications of Pneumatic system?
a) Aerospace
b) Packing systems
c) Mining
d) Agriculture equipment
Answer: b
Clarification: The Pneumatic systems are not used in Aerospace activities, Hydraulic systems are used. The other options are the applications of Pneumatic systems. Packing is the final operation done on the product of any industry. The Pneumatic hand tools are extensively employed in mines. They are also used in shears and Pneumatic systems.

9. What prevents the leakage of oil inside an unbalanced vane pump?
a) Vanes
b) Cylindrical rotor
c) Screw
d) Difference between the pressure of inlet and outlet
Answer: a
Clarification: The vanes are seated in the radial slots of the rotor and held against the casing by spring force or hydraulic force. Hence there will not be any leakage of oil between the vane tips and the casing. Still, there is a little amount of leakage and hence the volumetric efficiency will be around 95%.

10. Which among the following are not the main selection criteria for selection of hydraulic pumps?
a) Discharge
b) Pressure
c) Speed
d) Weight
Answer: d
Clarification: The weight is not the main selection criteria for selection of hydraulic pumps. There are different values for gear pumps, vane pumps and piston pumps for Pressure, Discharge and Speed which are predefined values.