Water Pump Horsepower Calculator for Sale

Pump Horsepower Formula:

\[ HP = \frac{Q \times H \times SG}{3960 \times \eta} \]

Flow Rate (Q):

GPM

Head (H):

Specific Gravity (SG):

(1 for water)

Efficiency (η):

decimal (0-1)

Pump Horsepower (HP):

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1. What is Pump Horsepower?

Pump horsepower (HP) is the power required to move a specific volume of fluid against a given head at a certain efficiency. It's crucial for selecting the right pump motor size for your application.

2. How Does the Calculator Work?

The calculator uses the standard pump horsepower formula:

\[ HP = \frac{Q \times H \times SG}{3960 \times \eta} \]

Where:

\( Q \) — Flow rate in gallons per minute (GPM)
\( H \) — Total dynamic head in feet (ft)
\( SG \) — Specific gravity of fluid (1 for water)
\( \eta \) — Pump efficiency (decimal 0-1)
3960 — Conversion factor (ft-lb/min per HP)

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

3. Importance of Horsepower Calculation

Details: Proper HP calculation ensures you select a pump that can handle your flow and head requirements without being oversized (wasting energy) or undersized (failing to meet demand).

4. Using the Calculator

Tips: Enter flow rate in GPM, head in feet, specific gravity (1 for water), and pump efficiency (typically 0.7-0.9 for centrifugal pumps). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between hydraulic HP and brake HP?
A: Hydraulic HP is the theoretical power needed to move the fluid. Brake HP (what this calculator shows) includes pump inefficiencies and is what the motor must provide.

Q2: How do I estimate pump efficiency?
A: Centrifugal pumps typically range from 50-85% efficiency. Check manufacturer curves or use 0.75 as a reasonable estimate if unknown.

Q3: Why is specific gravity important?
A: Heavier fluids (SG > 1) require more power to pump. For water, SG=1. For other fluids, use their density relative to water.

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

Q5: What about motor selection?
A: Motors come in standard sizes. Always round up to the next available motor size after adding your safety factor.