1. What is Full Load Amps (FLA)?

Full Load Amps (FLA) is the current a motor draws while operating at its rated load, voltage, and frequency. It's a crucial parameter for sizing circuit protection devices, conductors, and motor starters.

2. How Does the Calculator Work?

The calculator uses the standard three-phase motor current formula:

Where:

• \( I \) — Full load current (amps)
• \( P \) — Motor power rating (watts)
• \( V \) — Line voltage (volts)
• \( PF \) — Power factor (0-1, typically 0.85 for motors)
• \( \eta \) — Motor efficiency (0-1, typically 0.85-0.95)

Explanation: The formula accounts for the three-phase power system (√3 factor) and adjusts for real-world motor characteristics through power factor and efficiency.

3. Importance of FLA Calculation

Details: Proper FLA calculation ensures correct sizing of electrical components, prevents overheating, and maintains motor performance while meeting safety standards.

4. Using the Calculator

Tips: Enter motor power in watts, line voltage in volts, power factor (typically 0.85), and efficiency (typically 0.90). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between FLA and LRA?
A: FLA is the steady-state current at full load. LRA (Locked Rotor Amps) is the momentary current during startup (typically 5-7× FLA).

Q2: How does voltage affect FLA?
A: FLA is inversely proportional to voltage. A 10% voltage drop increases current by about 11% (assuming constant power).

Q3: What's a typical power factor for motors?
A: Induction motors typically have 0.85 PF at full load, lower at partial loads. Synchronous motors can achieve 1.0 PF.

Q4: Why include efficiency in the calculation?
A: Efficiency accounts for power losses (heat, friction). A 90% efficient motor draws more current than a 95% efficient one for the same output.

Q5: How to convert horsepower to watts?
A: 1 HP = 746 watts. For metric horsepower: 1 HP = 735.5 watts.