The starting torque in case of centrifugal pumps is generally

2 large and 1 small pumps can fill a water tank in 4 hours. 1 large and 3 small pumps can also fill the same water tank in 4 hours . How many hours will it take for 3 large 4 small pumps to fill the tank?

A

2 hours

B

2.5 hours

C

3 hours

D

3.5 hours

2 large and 1 small pumps can fill a water tank in 4 hours. One large and 3 small pumps can also fill the same water tank in 4 hours. how many hours will it take for 3 large and 4 small pumps to fill the tank?

A

2 hours

B

2.5 hours

C

3 hours

D

3.5 hours

The cost of manufacturing x water pumps is Tk.9000+400x. The amount received by selling these x water pumps is Tk. 500x. What is the least number of water pumps that must be manufactured and sold so that that the amount recieved is at least equal to the manufacturing cost ?

A

50

B

60

C

90

D

100

Reciprocating pumps compared to centrifugal pumps

A

Deliver liquid at uniform pressure

B

Can handle slurries more efficiently

C

Are not subject to air binding

D

Can be operated with delivery valve closed

Reciprocating pumps are no more to be seen in industrial applications (in comparison to centrifugal pumps) because of

A

High initial and maintenance cost

B

Lower discharge

C

Lower speed of operation

D

Necessity of air vessel

Reciprocating pumps are not able to compete with the centrifugal pump for industrial use, mainly because these pumps have

A

Very low speeds

B

Smaller discharge

C

Higher capital &maintenance cost

D

High vibrations

Centrifugal pumps as compared to reciprocating pumps

A

Run at a lower speed for the same discharge

B

Do not need priming

C

Deliver fluid with pulsating/fluctuating discharge

D

Can be run with discharge line valve closed for a short interval

Multistage centrifugal pumps are generally used for

A

High head

B

Low head but high discharge

C

Highly viscous liquid

D

Slurries of high solid concentration

The ratio of starting torque to full-load torque is least in case of

A

Series motors

B

Shunt motors

C

Compound motors

D

None of the above

Which of the following load normally needs starting torque more than the rated torque?

A

Blowers

B

Conveyors

C

Air compressors

D

Centrifugal pumps

The starting torque in case of centrifugal pumps is generally

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