Pump Horsepower Calculation Formula

Pump Horsepower Formula:

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

Flow Rate (Q):

gpm

Head (H):

Specific Gravity (SG):

dimensionless

Efficiency (η):

Pump Horsepower (HP):

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1. What is the Pump Horsepower Calculation Formula?

The Pump Horsepower Calculation Formula is used to determine the power required by a pump to move a fluid at a specified flow rate against a given head. It considers the fluid's specific gravity and the pump's efficiency to provide an accurate horsepower requirement.

2. How Does the Calculator Work?

The calculator uses the Pump Horsepower formula:

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

Where:

\( Q \) — Flow rate (gallons per minute, gpm)
\( H \) — Head (feet, ft)
\( SG \) — Specific gravity (dimensionless)
\( \eta \) — Efficiency (percentage, %)

Explanation: The formula calculates the theoretical horsepower required to pump a fluid, accounting for the fluid's properties and the pump's efficiency.

3. Importance of Pump Horsepower Calculation

Details: Accurate pump horsepower calculation is crucial for selecting the right pump motor, ensuring energy efficiency, and preventing motor overload in various industrial and commercial applications.

4. Using the Calculator

Tips: Enter flow rate in gpm, head in feet, specific gravity (typically 1.0 for water), and pump efficiency as a percentage. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is specific gravity and how do I determine it?
A: Specific gravity is the ratio of a fluid's density to water's density. For water, SG = 1.0. For other fluids, consult material safety data sheets or engineering references.

Q2: What is a typical pump efficiency range?
A: Pump efficiency typically ranges from 50% to 85%, depending on pump type, size, and operating conditions. Consult manufacturer specifications for exact values.

Q3: Why is the constant 3960 used in the formula?
A: The constant 3960 converts the units to horsepower (1 horsepower = 3960 gpm-ft-lb/min) when using gpm for flow and feet for head.

Q4: Can this formula be used for all types of pumps?
A: This formula provides a good estimate for centrifugal pumps. Positive displacement pumps may require different calculations due to their different operating characteristics.

Q5: How does fluid viscosity affect horsepower requirements?
A: Higher viscosity fluids require more horsepower to pump. The specific gravity alone doesn't account for viscosity effects, so additional calculations may be needed for highly viscous fluids.