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 formula:

Where:

• \( Q \) — Flow rate in gallons per minute (GPM)
• \( H \) — Total dynamic head in feet (ft)
• \( SG \) — Specific gravity of the fluid (1.0 for water)
• \( \eta \) — Pump efficiency as a 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 correct pump sizing, prevents motor overload, optimizes energy usage, and helps select appropriate motor and electrical components.

4. Using the Calculator

Tips: Enter flow rate in GPM, head in feet, specific gravity (1.0 for water), and pump efficiency (typically 0.7-0.9). 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 50-85% efficiency (0.5-0.85), with higher efficiency in larger, well-designed pumps.

Q2: How does specific gravity affect HP?
A: HP increases linearly with SG. Pumping syrup (SG=1.3) requires 30% more HP than water at the same flow and head.

Q3: What if my flow is in m³/h?
A: Convert to GPM first (1 m³/h ≈ 4.403 GPM) or use the metric formula with kW output.

Q4: Does this include safety factors?
A: No, engineers typically add 10-25% safety margin to calculated HP for motor selection.

Q5: What's the difference between BHP and WHP?
A: Brake HP (BHP) is power at pump shaft, Water HP (WHP) is hydraulic power delivered to fluid (WHP = Q×H×SG/3960).