1. What is Water Pump Horsepower?

Water pump horsepower (HP) is the power required to move a specific volume of fluid against a given head (pressure) at a specified efficiency. It's a crucial parameter for selecting and sizing pumps in various applications.

2. How Does the Calculator Work?

The calculator uses the standard pump horsepower formula:

Where:

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

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

3. Importance of Pump Horsepower Calculation

Details: Proper horsepower calculation ensures the pump can handle the required flow and pressure while operating efficiently. Undersizing leads to poor performance while oversizing wastes energy and increases costs.

4. Using the Calculator

Tips: Enter flow rate in GPM, total head in feet, specific gravity (1 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 total head?
A: Total head is the sum of static head (vertical distance), friction head (pipe resistance), and pressure head (system pressure).

Q2: What's typical pump efficiency?
A: Centrifugal pumps typically range from 50-85% efficiency, with higher efficiency in larger, well-designed pumps.

Q3: How does specific gravity affect HP?
A: Higher SG fluids require more power - double the SG means double the HP requirement for same flow and head.

Q4: What's the difference between BHP and WHP?
A: Brake horsepower (BHP) is power at pump shaft, while water horsepower (WHP) is power actually delivered to fluid (BHP × efficiency).

Q5: Should I add a safety factor?
A: Yes, typical practice is to add 10-20% safety factor to calculated HP for motor selection.