Pump Shaft Power Calculator:
Enter the values of hydraulic power, HP(kW) and efficiency, n to determine the value of Pump shaft power, SP(kW).
Pump Shaft Power Formula:
Pump shaft power signifies the mechanical power delivered by the motor’s shaft to the pump’s internal mechanism (usually the impeller) to move the liquid. Measured in watts (W) or hydraulic power (HP), it’s an essential parameter for understanding pump performance and efficiency.
Shaft power helps determine the appropriate motor size. A motor with insufficient power won’t be able to drive the pump effectively. Comparing SP to motor power reveals the pump’s efficiency. Lower SP compared to motor power indicates energy losses during conversion.
Here, motor power is typically rated in hydraulic power (HP), and pump efficiency (n) is a decimal value between 0 and 1 (often expressed as a percentage). A higher efficiency signifies less energy loss during conversion from electrical to mechanical power.
Pump efficiency typically ranges from 50% to 90%. The remaining power is lost due to factors like friction within the pump. Therefore, the pump shaft power is generally lower than the motor power.
Pump shaft power, SP(kW) in kilowatts is calculated by dividing the hydraulic power, HP(kW) in kilowatts by efficiency, n.
Pump shaft power, SP(kW) = HP(kW) * n
SP(kW) = shaftpower in kilowatts, kW.
HP(kW) = hydraulic shaft in kilowatts, kW.
n = efficiency.
Pump Shaft Power Calculation:
- A centrifugal pump motor has a rated power of 10 horsepower (HP) and an efficiency of 75%. What is the pump shaft power?
Given: HP(kW) = 10, n = 75% (convert to decimal: 0.75)
SP(kW) = HP(kW) / n
SP(kW) = 10 / 0.75
SP(kW) = 13.33kW.
- A pump requires 2 kW of shaft power to operate and has an efficiency of 85%. What is the minimum motor horsepower required?
Given: SP(kW) = 2000, n = 85%
SP(kW) = HP(kW) / n
HP(kW) = SP(kW) * n
HP(kW) = 2000 * 0.85
HP(kW) = 1.7kW.