1. What is a Pump Motor Horsepower Calculator?

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

Purpose: It helps engineers and technicians properly size pump motors 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)
• \( H \) — Total head (feet)
• \( \rho \) — Fluid density (pounds per gallon)
• \( \eta \) — Pump efficiency (decimal)

Explanation: The formula calculates the power needed to move a specific volume of fluid against a given pressure head, adjusted for pump efficiency.

3. Importance of Pump Horsepower Calculation

Details: Proper horsepower calculation ensures efficient pump operation, prevents motor overload, and helps select appropriately sized equipment.

4. Using the Calculator

Tips: Enter the flow rate in GPM, head in feet, fluid density (default 8.34 lb/gal for water), and efficiency (default 0.85). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is the constant 3960 in the formula?
A: It's a conversion factor that combines unit conversions to give results in horsepower (1 HP = 550 ft-lb/sec).

Q2: What's a typical pump efficiency value?
A: Most pumps operate between 70-90% efficiency (0.7-0.9). Centrifugal pumps typically range 0.6-0.85.

Q3: How do I determine total head?
A: Total head includes static head, friction losses, and pressure differences in the system.

Q4: What density should I use for other fluids?
A: For fluids other than water, use their specific weight (e.g., 6.6 lb/gal for gasoline, 10 lb/gal for brine).

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