1. What is Pump Horsepower?

Pump horsepower (HP) is the power required to drive a pump to move fluid at a specified flow rate against a given head. It accounts for the fluid properties (specific gravity) and pump efficiency.

2. How Does the Calculator Work?

The calculator uses the pump horsepower formula:

Where:

• \( Flow \) — Flow rate in gallons per minute (gpm)
• \( Head \) — Total dynamic head in feet
• \( SG \) — Specific gravity of the fluid (unitless)
• \( Efficiency \) — Pump efficiency as a decimal (0-1)
• 3960 — Conversion factor (foot-pounds per minute per horsepower)

Explanation: The equation calculates the power needed to move a fluid against gravity and system resistance, accounting for the pump's efficiency.

3. Importance of Pump HP Calculation

Details: Proper horsepower calculation ensures correct pump sizing, prevents motor overload, and optimizes energy efficiency in fluid systems.

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 is specific gravity?
A: The ratio of fluid density to water density at standard conditions. Water = 1.0, most oils = 0.7-0.9.

Q2: How do I estimate pump efficiency?
A: Typical centrifugal pumps have 70-90% efficiency. Check manufacturer curves for specific pumps.

Q3: What's the difference between brake HP and water HP?
A: Water HP is the theoretical power needed, while brake HP includes pump inefficiencies (what the motor must provide).

Q4: Why 3960 in the formula?
A: It's the conversion factor: 1 HP = 33,000 ft-lb/min, and 1 gallon water = 8.34 lb → 33,000/8.34 ≈ 3960.

Q5: How does viscosity affect HP?
A: Higher viscosity fluids require more power. For viscous fluids, use correction factors or specialized formulas.