1. What is Pump Motor Power?

Pump motor power is the mechanical power required by a pump to move a fluid at a specified flow rate against a specific head, taking into account the fluid's density and the pump's efficiency.

2. How Does the Calculator Work?

The calculator uses the pump power equation:

Where:

• \( P \) — Pump power (kW)
• \( Q \) — Flow rate (m³/s)
• \( H \) — Head (m)
• \( \rho \) — Density (kg/m³)
• \( g \) — Gravity (9.81 m/s²)
• \( \eta \) — Pump efficiency (0-1)

Explanation: The equation calculates the theoretical power required to move the fluid, then divides by the pump's efficiency to get the actual motor power required.

3. Importance of Pump Power Calculation

Details: Accurate pump power calculation is crucial for selecting the right motor size, ensuring energy efficiency, and preventing motor overload.

4. Using the Calculator

Tips: Enter flow rate in m³/s, head in meters, density in kg/m³ (1000 for water), and pump efficiency as a decimal (0.8 for 80%). All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is typical pump efficiency?
A: Centrifugal pumps typically range from 40-85% efficiency, with higher efficiencies for larger pumps at their best efficiency point.

Q2: How does viscosity affect pump power?
A: Higher viscosity fluids require more power and may reduce pump efficiency. Special corrections may be needed for viscous fluids.

Q3: What safety factor should I add?
A: Typically 10-25% additional power is added as a safety margin for motor selection.

Q4: How do I convert flow units?
A: 1 m³/s = 1000 L/s = 3600 m³/h. Make sure all units are consistent in the calculation.

Q5: What if my pump has variable speed?
A: The power calculation still applies, but power will vary with the cube of the speed change (Affinity Laws).