1. What is the Pump Power Equation?

The pump power equation calculates the required horsepower (HP) for a water pump based on flow rate, total head, specific gravity of the fluid, and pump efficiency. It's essential for selecting the right pump size for well systems.

2. How Does the Calculator Work?

The calculator uses the pump power equation:

Where:

• \( Q \) — Flow rate in gallons per minute (GPM)
• \( H \) — Total dynamic head in feet
• \( SG \) — Specific gravity of the fluid (1.0 for water)
• \( \eta \) — Pump efficiency (typically 0.7-0.9)
• 3960 — Conversion factor to horsepower

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

3. Importance of Proper Pump Sizing

Details: Correct pump sizing ensures efficient operation, prevents premature failure, and reduces energy costs. Undersized pumps can't deliver needed flow, while oversized pumps waste energy and may cause system damage.

4. Using the Calculator

Tips: Measure flow rate and total head accurately. For water, specific gravity is 1.0. Typical pump efficiency ranges from 70-90% (0.7-0.9). Always round up to the nearest standard pump size.

5. Frequently Asked Questions (FAQ)

Q1: What is total dynamic head?
A: The total height the pump must lift water (static head) plus friction losses in pipes (dynamic head), measured in feet.

Q2: How do I measure flow rate?
A: For existing wells, time how long it takes to fill a container of known volume. For new wells, consult drilling records.

Q3: What's a typical pump efficiency?
A: Submersible pumps typically 70-85%, jet pumps 50-70%. Higher quality pumps have better efficiency.

Q4: Should I add a safety factor?
A: Yes, add 10-20% to calculated HP to account for system variations and future needs.

Q5: What about motor size?
A: Motors are typically sized 25% larger than pump HP to prevent overload.