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Q BANK & ANSWER - ELECTRICAL ENGINEERING - PUMPS (RAILWAY)

1 If pump delivers no liquid, then probable cause is [ a ]

(a)Lack of prime 

(b) Gas or air in liquid

(c) Bent shaft 

(d) Moisture in lubricating oil

Answer : (a)Lack of prime 


2 If pump discharge pressure is low, then probable cause is [ b ]

(a) Lack of prime 

(b) Gas or air in liquid

(c) Bent shaft 

(d) Moisture in lubricating oil

Answer : (b) Gas or air in liquid


3 If there is excessive vibration in pump, then probable cause is [ c ]

(a) Lack of prime 

(b) Gas or air in liquid

(c) Bent shaft 

(d) Moisture in lubricating oil

Answer : (c) Bent shaft 


4 If the bearing of pump overheats, then probable cause is [ d ]

(a) Lack of prime 

(b) Gas or air in liquid

(c) Bent shaft 

(d) Moisture in lubricating oil

Answer : (d) Moisture in lubricating oil


5 If pump overloads the driver, then probable cause is [ a ]

(a) Packing too tight 

(b) Suction line not filled with liquid

(c) Gas or liquid in air 

(d) None of the above

Answer : (a) Packing too tight 


6 Which of the following is not a criteria of pump selection [ d ]

(a) Type of duty required 

(b) Details of head

(c) Duration of availability of power supply

(d) The look of pump.

Answer :  (d) The look of pump.


7. HS Pump works with suction head. [ b ]

(a) 15-20 feet head 

(b) 21-40 feet head

(c) 41-80 feet head 

(d) None of the above.

Answer : (b) 21-40 feet head


8. VS Pump works with total head [ b ]

(a) Upto 46 Mtrs. head. 

(b) 46-70 Mtrs. head

(c) 70-100 Mtrs. Head 

(d) None of the above

Answer : (b) 46-70 Mtrs. head


9. Motor of the VS pump is located [ a ]

(a) Above the ground level 

(b) Below the ground level

(c) Deep in the bore 

(d) None of the above

Answer : (a) Above the ground level 


10. Line shaft of the VS pump is lubricated [ c ]

(a) Spindle oil 

(b) Diesel oil

(c) Lub oil SAE-40/30 

(d) None of the above

Answer : (c) Lub oil SAE-40/30 


11. Priming is required for [ a ]

(a) HS Pump 

(b) VS Pump 

(c) Submersible Pump

Answer : (a) HS Pump 


12. RPM of submersible pump set is [ d ]

(a) 440 

(b) 1440 

(c) 380

 (d) 2800

Answer :  (d) 2800

13. Which pump is most suitable for deep & tilted bore [ c ]

(a) HS Pump

(b) VS Pump 

(c) Submersible 

(d) Jet pump

(e) None of above.

Answer :  (c) Submersible 

14. Redevelopment of bore is done [ b ]

(a) For smooth operation of pump

(b) For taking good yield for bore

(c) To maintain long life of bore

(d) To avoid the frequent failure of the pump

Answer : (b) For taking good yield for bore


15. Capacity of pump set is selected on the ground of [ a ]

(a) Yield, Static-water-level, Working-water-level.

(b) Location of bore

(c) Type of starter provided

(d) Quantity of water to be used.

Answer :(a) Yield, Static-water-level, Working-water-level.


16. Pump fails mostly due to [ b ]

(a) Less working

(b) Excessive working

(c) Incorrect operation

(d) Failure of pump

Answer :(b) Excessive working


17. Pump set motor burns due to [ a ]

(a) Single phasing

(b) Reverse phasing

(c) Over loading for a shorter period

(d) None of above.

Answer :(a) Single phasing


18. For a 10 HP pump set which type of starter is suitable [ b ]

(a) DOL 

(b) Start Delta 

(c) Auto Transformer

(d) None of the above

Answer :(b) Start Delta 
 

19. A 5 HP pump set draws current on full load [ c ]

(a) 5 A 

(b) 10 A 

(c) 7.5 A

(d) 6 A


Answer : (c) 7.5 A


20. Ammeter is provided in control panel of pump set to measure the [ d ]

(a) Voltage 

(b) Frequency 

(c) Power Factor 

(d)Current

Answer : (d)Current


21. No. of contractors provided in star-delta starter [ c ]

(a) 1 

(b) 2 

(c) 3 

(d) 4

Answer : (c) 3 


22. Pump Guard functions to protect the submersible pump set against [ e ]

a) Single Phasing

b) Reverse Phasing

c) Over Loading

d) Dry Running

e) All of above.

Answer :e) All of above.


23. Automation of pump set is done to [ d ]

a) To limit the working of pumps

b) To avoid the working of water

c) To save the electrical energy

d) To reduce the man power

e) All of the above.

Answer : d) To reduce the man power


24. Centralized control of pumps means [ b ]

a) Operation of pump from individual pump houses

b) Operation of all pumps from a single location

c) None of the above

Answer : b) Operation of all pumps from a single location


25. The functional head due to flow of water in the pipe line---- length of piping system. [ b ]

a) Inversely proportional to 

(b) Directly proportional to

(c) Constant and independent of 

(d) None of the above.

Answer : (b) Directly proportional to


26. The functional head due to flow of water in the pipe line---- Diameter of pipe. [ a ]

a) Inversely proportional to

b) Directly proportional to

(c) Constant and independent of

(d) None of the above.

Answer : a) Inversely proportional to


27. The functional head due to flow of water in pip line is directly proportional to---- of water.

a) Velocity 

b) (Square root of) Velocity

c) 1 / Velocity

d) Velocity2

Answer :  a) Velocity 

28. The average of velocity of water in the suction pipe --- the delivery pipe. [ a ]

a) Less than in 

(b) More than in

(c) Same as in 

(d) None of the above.

Answer :  a) Less than in 


29. Theoretically the maximum suction head for ordinary centrifugal pumps should not exceed. [ b ]

a) 20 feet 

(b) 34 feet 

(c) 10 feet

 (d) 5 feet.

Answer :  (b) 34 feet 


30. For vertical shaft pump and submersible pumps the suction head is always. [ a ]

(a) Positive 

(b) Negative 

(c) Zero 

(d) None of the above.

Answer :  (a) Positive 


31. The motor of vertical shaft, 75 HP rating pump is. [ c ]

(a) Force air cooled 

(b) Natural air cooled

(c) Water cooled. 

(d) None of the above.

Answer :(c) Water cooled. 


32. The specific speed of pump (in RPM) is the speed at which the impeller would run to give discharge of --- against head of ---- [ a ]

(a) 1 GPM, 1 Foot

(b) 1 GPH, 1 Foot

(c) 1 GPM, 34 feet

(d) 1 GPH, 34 feet

Answer : (a) 1 GPM, 1 Foot

 
33. The specific speed of pump is directly proportional to ---- where ‘Q’ is rate of discharge in GPH. [ a ]

(a) (Square root) Q 

(b) Q 

(c) Q2

(d) None of the above.

Answer : (a) (Square root) Q 


34. The specific speed of pump is directly proportional to --- where ‘N’ is speed of pump in RPM. [ b ]

(a) Square root (N) 

(b) N 

(c) N2 

(d) None of the above.

Answer : (b) N 


35. Positive displacement pumps are generally less efficient than centrifugal pumps. State whether the statement is true or false [ b ]

(a) True 

(b) False

Answer : (b) False


36. Installing larger diameter pipe in pumping system results in reduction in--------

a) static head 

b) frictional head 

c) both a and b 

d) neither a nor b

Answer : b) frictional head 


37. Generally water pipe lines are designed with water velocity of [ b ]

a) < 1 m/s 

b) up to 2.0 m/s 

c) > 2 m/s 

d) None of the above

Answer : b) up to 2.0 m/s 


38. What is the impact on flow and pressure when the impeller of a pump is trimmed? [ c ]


a) Flow decreases with increased pressure 

b) Both flow and pressure increases

c) Both pressure and flow decreases 

d) None of the above

Answer : c) Both pressure and flow decreases 


39. For high flow requirement, pumps are generally operated in [ a ]

a) parallel 

b) series 

c) any of the above 

d) none of the above

Answer : a) parallel 


40. “In case of throttling operation, the pump has to overcome additional pressure in order to deliver the reduced flow”. Please indicate whether this statement is [ a ]

a) True 

(b) False

Answer : a) True 


41. Friction losses in a pumping system is------ [ b ]

a) proportional to 1/Q 

b) proportional to 1/Q2

c) proportional to 1/Q3

d) proportional to 1/Q4

Answer : b) proportional to 1/Q2


42. For large capacity centrifugal pumps, design efficiencies are in the range of [ b ]

a) around 70% 

b) around 85% 

c) around 95% 

d) any of above

Answer : b) around 85% 


43. The moving part in centrifugal pump is ----- [ a ]

a) impeller 

b) diffuser 

c) both a & b 

d) neither a nor b

Answer :a) impeller 


44. The most efficient method of flow control in a pumping system is------- [ b ]

a) Throttling the flow 

b) Speed control 

c) Impeller trimming

 d) None

Answer : a) Throttling the flow 

45. In case of increased suction lift from open wells, the delivery flow rate-------- [ b ]

a) increases 

b) decreases 

c) remains same 

d) none of the above

Answer : b) decreases 
 

46. Pump efficiency generally increases with specific speed. State whether the statement is True or False. [ a ]

a) True 

(b) False

Answer :a) True 


47. Throttling the delivery valve of a pump results in increased ____. [ c ]

a) head 

b) power 

c) both (a) and (b) 

d) either (a) or (b)

Answer : c) both (a) and (b) 


48. The operating point in a pumping system is identified by [ c ]

a) Point of intersection of system curve and efficiency curve

b) Point of intersection of pump curve and theoretical power curve

c) Point of intersection of pump curve and system curve

d) Cannot be decided by pump characteristic curves

Answer : c) Point of intersection of pump curve and system curve


49. The intersection point of the pump curve and the system curve is called-------- [ b ]

a) Pump efficiency 

b) Best efficiency point

c) System efficiency 

d) None of the above

Answer : b) Best efficiency point

50. If the speed of a centrifugal pump is doubled, its power consumption increases by------- times. [ c ]

a) two 

b) four 

c) eight 

d) no change

Answer :c) eight 

51. Installation of Variable frequency drives (VFD) allows the motor to be operated with ____. [ a ]

a) lower start-up current 

b) higher start-up current

c) constant current 

d) none of the above

Answer :a) lower start-up current 


52. In case of centrifugal pumps, impeller diameter changes are generally limited to reducing the diameter to about ____ of maximum size. [ a ]

a) 75% 

b)50% 

c) 25% 

d) None of the above

Answer : a) 75% 


53. If the delivery valve of the pump is throttled such that it delivers 30% of the rated flow, one of the best options for improved energy efficiency would be [ c ]

a) Trimming of the impeller 

b) Replacing the motor

c) Replacing the impeller with a smaller size impeller 

d) None of the above

Answer :  c) Replacing the impeller with a smaller size impeller 


54. Small by-pass lines are installed some times to _____. [ c ]

a) control flow rate 

b) control pump delivery head

c) prevent pump running at zero flow 

d) reduce pump power consumption

Answer : c) prevent pump running at zero flow 

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