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Berechnen Sie pump power requirements aus flow rate, head, and efficiency. Find both hydraulic und shaft power in kW.
Required Shaft Power
7.85 kW
Required Shaft Power vs Flow Rate (Q)
Formel
## Pump Power Calculation The power a pump must supply depends on the flow rate, the head it must overcome, and pump efficiency. ### Formulas **Hydraulic power = rho g Q H** (useful work on the fluid) **Shaft power = rho g Q H / eta** (actual input from motor) where rho is fluid density, g = 9.81 m/s^2, Q is volumetric flow rate, H is total dynamic head, and eta is pump efficiency.
Lösungsbeispiel
A pump delivers 20 L/s of water against 30 m total head at 75% efficiency.
- 01Q = 20 L/s = 0.020 m^3/s
- 02Hydraulic power = 1000 x 9.81 x 0.020 x 30 = 5886 W = 5.89 kW
- 03Shaft power = 5.89 / 0.75 = 7.85 kW
- 04Select a motor of at least 7.5 kW (next standard size up).
Häufig Gestellte Fragen
What does total dynamic head include?
Total dynamic head = static lift (elevation difference) + friction head loss in pipes and fittings + velocity head at discharge + pressure head required at the outlet. It is the total energy per unit weight the pump must add.
What is a typical pump efficiency?
Centrifugal pumps typically operate at 60-85% efficiency at their best efficiency point (BEP). Small pumps tend toward 50-65%, large pumps 80-90%. Operating far from BEP reduces efficiency significantly.
How do I account for motor efficiency?
The electric motor also has losses. Total electrical input = shaft power / motor efficiency. Motors are typically 85-95% efficient. Specify the motor based on shaft power, and the electrical supply based on motor efficiency.
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