1. What is Brake Horsepower (BHP)?

Brake Horsepower (BHP) is the actual horsepower delivered to the pump shaft. It represents the power required by the pump to move the fluid at the specified flow rate against the given head, accounting for the pump's efficiency.

2. How Does the Calculator Work?

The calculator uses the Brake Horsepower formula:

Where:

• \( Q \) — Flow rate in gallons per minute (GPM)
• \( H \) — Total dynamic head in feet (ft)
• \( SG \) — Specific gravity of the fluid (1.0 for water)
• \( \eta \) — Pump efficiency as a decimal (0.0 to 1.0)
• 3960 — Conversion factor to convert to horsepower

Explanation: The equation calculates the power required by the pump after accounting for the pump's efficiency.

3. Importance of BHP Calculation

Details: Accurate BHP calculation is crucial for proper pump selection, motor sizing, and ensuring the pump operates efficiently within its designed parameters.

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., 85% = 0.85). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between BHP and WHP?
A: Brake Horsepower (BHP) is power at the pump shaft, while Water Horsepower (WHP) is the theoretical power required to move the fluid (BHP = WHP / efficiency).

Q2: What's a typical pump efficiency value?
A: Centrifugal pumps typically range from 50-85% efficiency, while positive displacement pumps can reach 90% or higher.

Q3: How does specific gravity affect BHP?
A: Higher specific gravity fluids require more power to pump (BHP is directly proportional to SG).

Q4: Why is the conversion factor 3960?
A: 3960 = (33,000 ft-lb/min per HP) / (8.33 lb/gal × specific gravity), combining unit conversions.

Q5: Should I add a safety factor to the calculated BHP?
A: Yes, it's common practice to add 10-20% safety factor when selecting a motor to account for variations and future needs.