1. What is the Pump Motor Power Formula?

The Pump Motor Power formula calculates the required horsepower for a pump based on flow rate, head, specific gravity, and pump efficiency. It's essential for proper pump selection and system design.

2. How Does the Calculator Work?

The calculator uses the US units formula:

Where:

• \( P \) — Motor power (hp)
• \( Q \) — Flow rate (gpm)
• \( H \) — Head (ft)
• \( SG \) — Specific gravity (decimal)
• \( Efficiency \) — Pump efficiency (decimal, 0-1)

Explanation: The formula accounts for the work needed to move fluid against gravity (head) and friction, adjusted for fluid density (SG) and pump efficiency.

3. Importance of Pump Power Calculation

Details: Accurate power calculation ensures proper motor sizing, prevents underpowering (which can cause failure) or overpowering (which wastes energy and money).

4. Using the Calculator

Tips: Enter flow rate in gpm, head in feet, specific gravity (1.0 for water), and pump efficiency (typically 0.7-0.9). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is specific gravity?
A: The ratio of fluid density to water density at standard conditions. Water = 1.0, most oils = 0.7-0.9.

Q2: How do I estimate pump efficiency?
A: Typical centrifugal pump efficiency ranges from 50% to 85%. Check manufacturer data for specific pumps.

Q3: What's the difference between hydraulic and brake horsepower?
A: Hydraulic HP is fluid power, brake HP is power at pump shaft. This calculator gives brake HP including efficiency.

Q4: Can I use this for viscous fluids?
A: This is for Newtonian fluids. For viscous fluids, correction factors are needed.

Q5: How do I convert to metric units?
A: For kW = (Q(m³/h) × H(m) × SG) / (367 × Efficiency). 1 hp = 0.746 kW.