1. What is Three-Phase Motor FLA?

Full Load Amps (FLA) is the current a three-phase motor draws while operating at its rated load and voltage. It's crucial for proper circuit protection and motor selection.

2. How Does the Calculator Work?

The calculator uses the three-phase motor current formula:

Where:

• \( I \) — Full load current (amps)
• \( P \) — Motor power (watts)
• \( V \) — Line voltage (volts)
• \( PF \) — Power factor (0-1)
• \( \eta \) — Motor efficiency (0-1)
• \( \sqrt{3} \) — Constant for three-phase systems (≈1.732)

Explanation: The formula accounts for real power (P), voltage, and the motor's power factor and efficiency to determine the actual current draw.

3. Importance of FLA Calculation

Details: Knowing the FLA is essential for selecting proper wire sizes, circuit breakers, overload protection, and ensuring safe motor operation.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between FLA and LRA?
A: FLA is full load current during normal operation, while LRA (Locked Rotor Amps) is the current during startup (typically 5-7 times higher than FLA).

Q2: How do I find my motor's power factor?
A: Check motor specifications or use typical values (0.85 for most industrial motors, 0.95 for high-efficiency motors).

Q3: Can I use this for single-phase motors?
A: No, single-phase motors use a different formula without the √3 factor.

Q4: What if my motor power is in horsepower?
A: Convert horsepower to watts (1 HP = 746 watts) before using the calculator.

Q5: Why is efficiency important in the calculation?
A: Efficiency accounts for power losses in the motor, so the actual current draw is higher than theoretical calculations without efficiency.