Pumps and Motors Flashcards

What is the primary purpose of a pump impeller in a centrifugal pump?

Answer: To convert mechanical energy into fluid velocity

The impeller rotates to impart velocity to the fluid, converting mechanical energy from the motor into kinetic energy in the water.

A pump is experiencing cavitation. Which operational change would most likely resolve this issue?

Answer: Reduce the suction lift or increase suction head

Reducing suction lift or increasing suction head raises the pressure at the pump inlet above the vapor pressure of water, preventing vapor bubble formation.

What does NPSH stand for in pump terminology?

Answer: Net Positive Suction Head

NPSH (Net Positive Suction Head) is the total head of liquid at the pump suction, used to determine if cavitation will occur.

A three-phase motor is running on two phases only due to a blown fuse. What will most likely happen?

Answer: The motor will overheat and may burn out

Single-phasing causes unequal current distribution, excessive heat buildup, and can destroy motor windings if not quickly corrected.

Which type of pump is best suited for high-flow, low-head water transmission applications at a water treatment plant?

Answer: Centrifugal pump

Centrifugal pumps are ideal for high-flow, low-to-moderate head applications and are the most common pump type in water treatment.

What is the function of a mechanical seal in a centrifugal pump?

Answer: To prevent leakage along the pump shaft

A mechanical seal prevents water from leaking out along the rotating shaft where it passes through the pump casing.

When reading a pump curve, what does the intersection of the pump curve and system curve represent?

Answer: The actual operating point of the pump

The intersection of the pump curve and system curve is the operating point, where the pump will naturally operate given the system's resistance.