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 crucial parameter in pump selection and system design.

2. How Does the Calculator Work?

The calculator uses the pump horsepower formula:

Where:

• \( Q \) — Flow rate (gallons per minute, GPM)
• \( H \) — Total dynamic head (feet, ft)
• \( SG \) — Specific gravity (dimensionless)
• \( \eta \) — Pump efficiency (decimal, 0-1)
• 3960 — Conversion factor (ft·lb/min per HP)

Explanation: The equation calculates the power needed to move a fluid against gravity and system resistance, accounting for the pump's mechanical efficiency.

3. Importance of Pump HP Calculation

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 0.7-0.9). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

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

Q2: How does specific gravity affect HP?
A: Higher SG fluids (denser than water) require more power to pump at the same flow rate and head.

Q3: What's a typical pump efficiency?
A: Centrifugal pumps typically range from 50-85% efficiency, with larger pumps generally more efficient.

Q4: Why is the conversion factor 3960?
A: It converts (GPM × ft × lb/gal) to HP: (8.34 lb/gal × 60 min/hr × 550 ft·lb/sec/HP).

Q5: How do I account for motor efficiency?
A: Divide the calculated HP by motor efficiency to get required input power.