1. What is the Pump Power Equation?

Definition: This calculator determines the horsepower required by a pump based on flow rate, total head, fluid density, and pump efficiency.

Purpose: It helps engineers and technicians properly size pumps for various fluid transfer applications.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( HP \) — Horsepower required
• \( Q \) — Flow rate (gallons per minute, GPM)
• \( H \) — Total head (feet)
• \( \rho \) — Fluid density (pounds per gallon, lb/gal)
• \( \eta \) — Pump efficiency (decimal, 0-1)

Explanation: The formula calculates the theoretical power required to move the fluid, then divides by efficiency to get actual power needed.

3. Importance of Pump Power Calculation

Details: Accurate power calculation ensures proper pump selection, prevents under-sizing (which can cause failure) and over-sizing (which wastes energy).

4. Using the Calculator

Tips: Enter the flow rate in GPM, total head in feet, fluid density (default 8.34 lb/gal for water), and pump efficiency (default 0.8 for 80%). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is the 3960 constant in the formula?
A: It's a conversion factor that combines unit conversions to give horsepower directly.

Q2: What's a typical pump efficiency value?
A: Centrifugal pumps typically range from 50-85% efficiency (0.5-0.85), with 0.8 being a common design value.

Q3: How do I determine total head?
A: Total head includes static head (vertical distance) plus friction losses in pipes and fittings.

Q4: What density should I use for other fluids?
A: For other fluids, use their specific weight divided by 7.48 (gallons per cubic foot). Example: SAE 30 oil is ~7.0 lb/gal.

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