1. What is the Pump HP Equation?

The pump horsepower equation calculates the power required to move fluid through a system 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 pump power equation:

Where:

• \( Q \) — Flow rate in gallons per minute (GPM)
• \( H \) — Total dynamic head in feet (ft)
• \( SG \) — Specific gravity of fluid (1 for water)
• \( \eta \) — Pump efficiency (decimal 0-1)
• 3960 — Conversion factor (ft·lb/min per HP)

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

3. Importance of Pump Power Calculation

Details: Accurate power calculation is essential for proper pump selection, motor sizing, and energy consumption estimation in fluid systems.

4. Using the Calculator

Tips: Enter flow rate in GPM, head in feet, specific gravity (1 for water), and pump efficiency as 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 50-85% efficiency, with higher efficiency in larger, well-designed pumps.

Q2: How does specific gravity affect HP?
A: HP increases linearly with specific gravity. Denser fluids require more power to pump at the same flow rate and head.

Q3: What is total dynamic head?
A: The total equivalent height the pump must overcome, including static lift, friction losses, and pressure differences.

Q4: Should I add a safety factor?
A: Yes, it's common to add 10-20% safety factor to the calculated HP for operational variations and future needs.

Q5: Can this be used for other pump types?
A: This equation is primarily for centrifugal pumps. Positive displacement pumps use different calculations.