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, accounting for the fluid's specific gravity and the pump's efficiency. It's a critical parameter in pump selection and system design.

2. How Does the Calculator Work?

The calculator uses the pump horsepower equation:

Where:

• \( Q \) — Flow rate (gallons per minute, GPM)
• \( H \) — Total dynamic head (feet, ft)
• \( SG \) — Specific gravity of the fluid (dimensionless)
• \( \eta \) — 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 the pump's efficiency to get actual required horsepower.

3. Importance of Pump Calculations

Details: Accurate horsepower calculation ensures proper pump selection, prevents motor overload, and optimizes energy consumption in fluid systems.

4. Using the Calculator

Tips: Enter flow rate in GPM, head in feet, specific gravity (1.0 for water), and pump efficiency (typically 0.6-0.85). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical pump efficiency value?
A: Centrifugal pumps typically range from 60-85% efficiency, while positive displacement pumps can reach 90% or higher.

Q2: How does specific gravity affect HP?
A: HP increases linearly with specific gravity. Pumping a fluid with SG=1.5 requires 50% more power than water (SG=1.0).

Q3: What if my flow is in m³/h instead of GPM?
A: Convert to GPM first (1 m³/h ≈ 4.403 GPM) or modify the equation to use consistent units.

Q4: Why is head measured in feet?
A: The equation uses feet because the conversion factor 3960 is based on ft·lb/min per HP. For meters, use 102 instead of 3960.

Q5: Should I add a safety factor?
A: Yes, it's common to add 10-20% to the calculated HP to account for system variations and future needs.