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. For submersible water pumps, it determines the motor size needed for the application.

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 (ft)
• \( SG \) — Specific gravity (1.0 for water)
• \( \eta \) — Pump efficiency (decimal from 0 to 1)
• 3960 — Conversion factor (foot-pounds per minute per horsepower)

Explanation: The formula calculates the power needed to move water against gravity and system resistance, accounting for pump efficiency.

3. Importance of Pump HP Calculation

Details: Proper HP calculation ensures the pump motor is correctly sized - too small will underperform, too large wastes energy and may cause premature wear.

4. Using the Calculator

Tips:

• Measure flow rate (GPM) from pump specifications or system requirements
• Total head includes vertical lift plus friction losses
• Typical submersible pump efficiency ranges from 0.5 to 0.85
• For water, specific gravity remains 1.0

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between brake HP and water HP?
A: Water HP is theoretical power needed to move water, while brake HP includes pump inefficiencies (what the motor must actually deliver).

Q2: How do I account for friction losses?
A: Friction losses should be calculated separately and added to the static head to get total head (H).

Q3: What's a typical efficiency for submersible pumps?
A: Efficiency typically ranges from 50-85%, with higher efficiency in larger, well-designed pumps.

Q4: Should I round up the HP when selecting a pump?
A: Yes, always select the next available motor size above your calculated HP requirement.

Q5: Does this work for other fluids besides water?
A: Yes, just adjust the specific gravity (SG) for the fluid being pumped.