1. What is Full Load Amps?

Full Load Amps (FLA) is the current a motor draws while operating at its rated horsepower with rated voltage and frequency. It's a crucial parameter for motor selection, circuit protection, and wire sizing.

2. How Does the Calculator Work?

The calculator uses the standard FLA formula for 3-phase motors:

Where:

• 40 — Motor horsepower (HP)
• 746 — Conversion factor from HP to Watts
• √3 — Constant for 3-phase power calculation (≈1.732)
• Voltage — Line-to-line voltage (V)
• Power Factor — Ratio of real power to apparent power (0-1)
• Efficiency — Motor efficiency (0-1)

Explanation: The formula converts horsepower to watts, then calculates the current required accounting for power factor and efficiency losses.

3. Importance of FLA Calculation

Details: Knowing FLA is essential for proper motor circuit design, including conductor sizing, overload protection, and starter selection. It helps prevent equipment damage and ensures safe operation.

4. Using the Calculator

Tips: Enter voltage in volts (typically 208, 230, 460, or 575 for industrial motors). Power factor is usually 0.8-0.95 for efficient motors. Efficiency ranges from 0.85-0.95 for premium efficiency motors.

5. Frequently Asked Questions (FAQ)

Q1: Why is 746 used in the formula?
A: 746 watts equals 1 horsepower, so we multiply HP by 746 to convert to watts before calculating current.

Q2: What's the difference between FLA and LRA?
A: FLA is running current at full load, while LRA (Locked Rotor Amps) is the much higher starting current (typically 5-7× FLA).

Q3: How does voltage affect FLA?
A: FLA is inversely proportional to voltage. Higher voltage means lower current for the same power.

Q4: What if my motor is single-phase?
A: This calculator is for 3-phase motors. Single-phase motors use a different formula without the √3 factor.

Q5: How accurate is this calculation?
A: It provides theoretical FLA. Actual values may vary slightly due to manufacturing tolerances and operating conditions.