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 formula calculates the power needed to move a fluid, accounting for the energy required to overcome elevation changes, friction losses, and the fluid's density.

3. Importance of Pump HP Calculation

Details: Accurate horsepower calculation ensures proper pump selection, prevents under/over-sizing, and helps determine motor requirements and energy consumption.

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 require more power to pump (HP is directly proportional to SG).

Q3: What's a typical pump efficiency?
A: Centrifugal pumps typically range from 60-85% efficiency, while positive displacement pumps can reach 90%+.

Q4: Why is the conversion factor 3960?
A: It comes from 1 HP = 33,000 ft-lb/min and 1 gallon water = 8.34 lb (33,000/8.34 ≈ 3960).

Q5: Should I add a safety factor?
A: Yes, typically add 10-20% to the calculated HP for safety margins and future capacity.