1. What is Motor Load Calculation?

Definition: This calculator computes the power consumption of a three-phase motor based on voltage, current, and power factor.

Purpose: It helps electrical engineers and technicians determine the actual power draw of three-phase motors in various applications.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( P_w \) — Power in watts
• \( V \) — Line voltage (volts)
• \( I \) — Line current (amps)
• \( PF \) — Power factor (unitless, 0-1)
• \( \sqrt{3} \) — Constant for three-phase systems (≈1.732)

Explanation: The formula accounts for all three phases in a balanced three-phase system, with the power factor representing the phase difference between voltage and current.

3. Importance of Motor Load Calculation

Details: Accurate motor power calculation is essential for proper electrical system design, energy efficiency analysis, and equipment sizing.

4. Using the Calculator

Tips: Enter the line voltage in volts, line current in amps, and power factor (default 0.8). All values must be > 0, with PF ≤ 1.

5. Frequently Asked Questions (FAQ)

Q1: What is power factor?
A: Power factor is the ratio of real power to apparent power, representing how effectively current is being converted into useful work.

Q2: What's a typical power factor for motors?
A: Induction motors typically have power factors between 0.7-0.9, depending on load and design.

Q3: Can I use this for single-phase motors?
A: No, for single-phase use \( P_w = V \times I \times PF \) (without the √3 factor).

Q4: How do I measure line current?
A: Use a clamp meter on any one of the three phase conductors while the motor is running.

Q5: Why does three-phase power use √3?
A: The √3 factor accounts for the 120° phase difference between the three phases in a balanced system.