1. What is 3-Phase Motor FLA?

Full Load Amps (FLA) is the current a motor draws while operating at its rated load and voltage. For 3-phase motors, this calculation considers power, voltage, power factor, and efficiency.

2. How Does the Calculator Work?

The calculator uses the 3-phase FLA formula:

Where:

• \( I \) — Full load current (amps)
• \( P \) — Motor power rating (watts)
• \( V \) — Line voltage (volts)
• \( PF \) — Power factor (0-1)
• \( \eta \) — Motor efficiency (0-1)

Explanation: The formula accounts for the three-phase power relationship and the motor's power factor and efficiency.

3. Importance of FLA Calculation

Details: Knowing the full load current is essential for proper wire sizing, circuit breaker selection, and overload protection in motor circuits.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

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

Q2: How does voltage affect FLA?
A: FLA is inversely proportional to voltage. Higher voltage means lower current for the same power.

Q3: What's a typical power factor for motors?
A: Induction motors typically have 0.85-0.95 PF at full load, lower at partial loads.

Q4: Why include efficiency in the calculation?
A: Efficiency accounts for power losses in the motor, giving the true current drawn from the supply.

Q5: Can I use this for single-phase motors?
A: No, single-phase motors use a different formula: I = P / (V × PF × η).