1. What is Full Load Current?

Full Load Current (FLC) is the maximum current that a motor draws from the power supply when operating at its rated power under full load conditions. It's a critical parameter for sizing circuit protection devices and conductors.

2. How Does the Calculator Work?

The calculator uses the full load current formula for three-phase AC motors:

Where:

• \( I \) — Full load current (amps)
• \( P \) — Motor power rating (watts)
• \( V \) — Line voltage (volts)
• \( PF \) — Power factor (0.1-1.0)
• \( \eta \) — Motor efficiency (0.1-1.0)

Explanation: The formula accounts for the three-phase power (√3 factor), power factor (ratio of real power to apparent power), and motor efficiency.

3. Importance of Full Load Current Calculation

Details: Accurate FLC calculation is essential for proper motor protection, preventing overheating, and ensuring correct sizing of circuit breakers, fuses, and wiring.

4. Using the Calculator

Tips: Enter motor power in watts, line voltage in volts, power factor (typically 0.8-0.95 for motors), and motor efficiency (typically 0.85-0.95). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between FLC and locked rotor current?
A: FLC is the steady-state current at full load, while locked rotor current (5-7× FLC) occurs during motor startup.

Q2: How does voltage affect full load current?
A: Current is inversely proportional to voltage - doubling voltage halves the current for the same power.

Q3: What's a typical power factor for motors?
A: Induction motors typically have 0.8-0.9 PF at full load, lower at partial loads.

Q4: Why does efficiency matter in current calculation?
A: Efficiency accounts for power losses - a 90% efficient motor draws more current than a 95% efficient one for the same output.

Q5: Can this be used for single-phase motors?
A: No, single-phase motors use I = P/(V × PF × η) without the √3 factor.