1. What is Pump Power Calculation?

The pump power calculation determines the horsepower required by a pump motor to move fluid at a specified flow rate against a given head, accounting for fluid properties and pump efficiency.

2. How Does the Calculator Work?

The calculator uses the hydraulic power formula:

Where:

• \( Flow\ Rate \) — Volumetric flow rate in gallons per minute (GPM)
• \( Head \) — Total dynamic head in feet
• \( Specific\ Gravity \) — Ratio of fluid density to water density (dimensionless)
• \( Efficiency \) — Pump efficiency as a decimal (0-1)
• 3960 — Conversion factor to get horsepower

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

3. Importance of Power Calculation

Details: Proper power calculation ensures correct motor sizing, prevents underpowering (which can cause failure) or overpowering (which wastes energy and increases costs).

4. Using the Calculator

Tips: Enter flow rate in GPM, head in feet, specific gravity (1.0 for water), and pump efficiency (typically 0.7-0.9 for centrifugal pumps). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is typical pump efficiency?
A: Centrifugal pumps typically range from 70-90% efficiency, while positive displacement pumps can reach 90-95%.

Q2: How does viscosity affect power requirements?
A: Higher viscosity fluids require more power, which is accounted for in the specific gravity and may require viscosity corrections.

Q3: What if my pump has variable speed?
A: This calculation gives power at the specified operating point. Variable speed pumps will have different power requirements at different speeds.

Q4: Should I add a safety factor?
A: It's common practice to add 10-20% to the calculated power to account for system losses and future demands.

Q5: How do I convert to kW?
A: Multiply HP by 0.746 to get kilowatts (kW). 1 HP = 0.746 kW.