Brake Horsepower Formula For Pump

Brake Horsepower Formula:

\[ BHP = \frac{GPM \times Head \times SG}{3960 \times Eff} \]

GPM (Gallons Per Minute):

GPM

Head:

feet

Specific Gravity (SG):

Efficiency (Eff):

decimal

Brake Horsepower (BHP):

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1. What Is Brake Horsepower For Pump?

Brake Horsepower (BHP) is the actual horsepower delivered to the pump shaft, representing the power required to drive the pump. It accounts for the pump's efficiency and is used to determine the motor size needed for proper pump operation.

2. How Does The Calculator Work?

The calculator uses the brake horsepower formula:

\[ BHP = \frac{GPM \times Head \times SG}{3960 \times Eff} \]

Where:

\( BHP \) — Brake Horsepower (HP)
\( GPM \) — Flow rate in gallons per minute
\( Head \) — Total dynamic head in feet
\( SG \) — Specific gravity of the fluid
\( Eff \) — Pump efficiency (decimal value)
\( 3960 \) — Conversion constant

Explanation: This formula calculates the actual power required at the pump shaft, considering the hydraulic power needed to move the fluid and the pump's mechanical efficiency.

3. Importance Of BHP Calculation

Details: Accurate BHP calculation is essential for proper pump selection, motor sizing, energy consumption estimation, and ensuring the pump operates within its designed parameters to prevent overload and equipment failure.

4. Using The Calculator

Tips: Enter GPM as gallons per minute, Head in feet, Specific Gravity (1.0 for water), and 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 BHP and WHP?
A: Brake Horsepower (BHP) is power at the pump shaft, while Water Horsepower (WHP) is the hydraulic power delivered to the fluid. BHP = WHP / Efficiency.

Q2: Why is 3960 used in the formula?
A: 3960 is a conversion constant that incorporates units conversion from (GPM × feet × lb/gal) to horsepower.

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

Q4: How does specific gravity affect BHP?
A: Higher specific gravity fluids require more power to pump, as BHP is directly proportional to specific gravity.

Q5: Should motor size match calculated BHP exactly?
A: No, motors are typically sized 10-25% larger than calculated BHP to provide safety margin and account for system variations.