1. What is Pump Horsepower?

Pump horsepower (HP) is the power required to move a fluid at a specified flow rate against a given head pressure, accounting for the pump's efficiency. It's a critical parameter for selecting and sizing pumps in various applications.

2. How Does the Calculator Work?

The calculator uses the 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 (ft-lb/min per HP)

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

3. Importance of Pump HP Calculation

Details: Proper horsepower calculation ensures you select a pump that can handle your flow and head requirements without being oversized (wasting energy) or undersized (failing to meet demand).

4. Using the Calculator

Tips:

• For water applications, specific gravity is 1.0
• Typical pump efficiencies range from 0.5 to 0.9 (50-90%)
• Total head includes static head, friction losses, and pressure differences

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between brake HP and water HP?
A: Water HP is theoretical power to move fluid, while brake HP includes pump inefficiencies (water HP divided by efficiency).

Q2: How do I determine total head?
A: Total head = static head (vertical distance) + friction losses + pressure head (if applicable).

Q3: What's a typical pump efficiency?
A: Centrifugal pumps typically range from 50-85% efficiency, while positive displacement pumps can reach 90%.

Q4: How does viscosity affect horsepower?
A: Higher viscosity fluids require more power - use specific gravity of the actual fluid and consider efficiency reductions.

Q5: Should I add a safety factor?
A: Many engineers add 10-20% to calculated HP to account for system variations and future demands.