1. What is the Pump Horsepower Equation?

The pump horsepower equation calculates the power required to move a fluid through a system based on flow rate, head, specific gravity, and pump efficiency.

2. How Does the Calculator Work?

The calculator uses the pump horsepower equation:

Where:

• \( Q \) — Flow rate (gallons per minute, GPM)
• \( H \) — Total head (feet, ft)
• \( SG \) — Specific gravity (dimensionless, 1 for water)
• \( \eta \) — Pump efficiency (decimal between 0 and 1)
• 3960 — Conversion factor (foot-pounds per minute per horsepower)

Explanation: The equation accounts for the work needed to move a specific volume of fluid against a certain pressure head, adjusted for fluid density and pump efficiency.

3. Importance of Pump Calculations

Details: Accurate pump calculations are crucial for proper pump selection, energy efficiency, and system design. Underestimating can lead to pump failure, while overestimating wastes energy and money.

4. Using the Calculator

Tips: Enter flow rate in GPM, head in feet, specific gravity (1 for water), and pump efficiency as a decimal (e.g., 0.85 for 85%). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is typical pump efficiency?
A: Centrifugal pumps typically range from 50-85% efficiency, while positive displacement pumps can reach 90% or higher.

Q2: How do I determine total head?
A: Total head includes static head (vertical distance) plus friction losses in pipes and fittings.

Q3: What's the difference between water and brake horsepower?
A: Water HP is the theoretical power needed to move the fluid. Brake HP includes pump inefficiencies (what the motor must deliver).

Q4: How does viscosity affect these calculations?
A: High viscosity fluids require more power and reduce pump efficiency. Specialized equations may be needed for viscous fluids.

Q5: What safety factors should I consider?
A: Engineers often add 10-20% to calculated HP to account for system variations and future needs.