Pump Power Calculation Formula

Pump Power Formula:

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

Flow Rate (Q):

GPM

Head (H):

Specific Gravity (SG):

Efficiency (η):

(0-1)

Pump Brake Horsepower (P):

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1. What is the Pump Power Calculation Formula?

The Pump Power Calculation Formula calculates the brake horsepower required by a pump to move fluid at a specified flow rate against a given head, taking into account the fluid's specific gravity and the pump's efficiency.

2. How Does the Calculator Work?

The calculator uses the pump power formula:

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

Where:

\( P \) — Pump brake horsepower (HP)
\( Q \) — Flow rate (GPM)
\( H \) — Head (ft)
\( SG \) — Specific gravity (-)
\( \eta \) — Pump efficiency (0-1)

Explanation: The formula calculates the actual power required by the pump shaft, accounting for energy losses through the pump efficiency factor.

3. Importance of Pump Power Calculation

Details: Accurate pump power calculation is essential for proper pump selection, motor sizing, energy consumption estimation, and system design optimization in various industrial and commercial applications.

4. Using the Calculator

Tips: Enter flow rate in GPM, head in feet, specific gravity (1.0 for water), and pump efficiency as a decimal (e.g., 0.75 for 75% efficiency). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between brake horsepower and water horsepower?
A: Brake horsepower is the power input to the pump shaft, while water horsepower is the hydraulic power delivered to the fluid. BHP = WHP / efficiency.

Q2: Why is specific gravity important in pump calculations?
A: Specific gravity affects the fluid density, which directly impacts the power required to pump the fluid. Heavier fluids require more power.

Q3: What are typical pump efficiency values?
A: Pump efficiencies typically range from 50% to 85%, depending on pump type, size, and operating conditions.

Q4: Can this formula be used for all pump types?
A: This formula is generally applicable to centrifugal pumps. Positive displacement pumps may require different calculations.

Q5: How does head affect pump power requirements?
A: Higher head requirements directly increase power consumption, as more energy is needed to overcome greater resistance.