Which factor is directly linked to the speed of the impeller?

Which factor is directly linked to the speed of the impeller?

• A. Speed at which the impeller is turning
• B. Amount of water being discharged
• C. Pressure of incoming water
• D. Type of seal used

Answer: (A)

The turning speed of the impeller is the direct control on how much energy is delivered to the fluid. When the impeller spins faster, its blades interact with the water more quickly, accelerating more water per unit time and creating higher velocity and pressure in the flow. This rotational speed is set by the drive motor (the RPM), so it directly determines the impeller’s speed. The other factors describe the system’s response rather than what sets the speed. The amount of water discharged depends on the system resistance and the impeller speed; the pressure of incoming water is a boundary condition at the inlet; and the type of seal affects efficiency and losses but does not set how fast the impeller rotates.

The turning speed of the impeller is the direct control on how much energy is delivered to the fluid. When the impeller spins faster, its blades interact with the water more quickly, accelerating more water per unit time and creating higher velocity and pressure in the flow. This rotational speed is set by the drive motor (the RPM), so it directly determines the impeller’s speed.

The other factors describe the system’s response rather than what sets the speed. The amount of water discharged depends on the system resistance and the impeller speed; the pressure of incoming water is a boundary condition at the inlet; and the type of seal affects efficiency and losses but does not set how fast the impeller rotates.