1. What is a Pump Motor kW Calculator?

Definition: This calculator estimates the required motor power in kilowatts for a pump based on fluid properties and system requirements.

Purpose: It helps engineers and technicians properly size pump motors for various applications.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( kW \) — Pump motor power (kilowatts)
• \( \rho \) — Fluid density (kg/m³)
• \( g \) — Gravitational acceleration (9.81 m/s²)
• \( Q \) — Flow rate (m³/s)
• \( H \) — Total dynamic head (m)
• \( \eta \) — Pump efficiency (0-1)

Explanation: The formula calculates the hydraulic power required to move the fluid and divides by pump efficiency to determine motor power.

3. Importance of Pump Motor Sizing

Details: Proper motor sizing ensures efficient operation, prevents overload conditions, and reduces energy costs.

4. Using the Calculator

Tips: Enter fluid density (default 1000 kg/m³ for water), gravity (default 9.81 m/s²), flow rate, head, and pump efficiency (default 0.8). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical pump efficiency value?
A: Centrifugal pumps typically range from 0.7-0.9 (70-90% efficiency) depending on size and design.

Q2: How do I convert flow rate from m³/h to m³/s?
A: Divide the m³/h value by 3600 (1 m³/h = 1/3600 m³/s).

Q3: What affects total dynamic head?
A: Static head, friction losses, pressure differences, and elevation changes all contribute to total head.

Q4: Should I add a safety factor?
A: Yes, typically add 10-20% to the calculated power for safety margin and future needs.

Q5: How does fluid viscosity affect the calculation?
A: Higher viscosity fluids may require more power and reduce pump efficiency.