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What is Full Load Amps? – FLA Explained

Written by Edwin Jones / Fact checked by Andrew Wright

What Is Full Load Amps

If you’re an electrical enthusiast, you may have encountered the term “Full Load Amps” or “FLA.” But what exactly does it mean, and why is it important in electrical systems?

In this article, we will comprehensively answer your question, “What is full load amps?” Let’s understand its definition, explore its significance in electrical systems, and discuss the amperage calculation methods and factors that affect it below.

Understanding Full Load Amps

1. Definition and Explanation


Full load amps, or FLA in electrical terms, refers to the maximum current drawn by an electrical device or motor when operating at its full load capacity. The lower the FLA, the more efficient the equipment is.

2. Importance in Electrical Systems


Understanding full load amps is crucial for several reasons. First, it enables engineers and electricians to select the proper electrical components and protection devices to ensure the motor’s safe and efficient operation, such as fuses and circuit breakers.

Second, full load amps play a significant role in equipment maintenance. Regular FLA monitoring helps identify deviations from normal operating conditions, indicating potential issues with the device or motor.

This proactive approach ensures timely maintenance or repairs, preventing costly breakdowns and downtime.

3. Calculating Full Load Amps

Calculating full load amps involves considering several crucial factors, including the power rating, voltage supply, efficiency, and power factor. You can determine the FLA required for the electrical system through precise calculation methods.

Let’s explore how the full load amps calculator works with some examples:

  • For a Single-Phase Circuit, the formula is:

\frac{{\text{kW} \times 1000}}{{V \times \text{PF} \times \eta}}

Suppose you have a 220V 5 kW motor with a power factor (PF) of 0.8 and an efficiency rating (η) of 88%. The calculation will be:

\frac{{5 \, \text{kW} \times 1000}}{{220 \, \text{V} \times 0.8 \times 0.88}} = 32.28 \, \text{amps}

This means the 5-kW motor has a full load amp rating of 32.28 in a single-phase system.

  • For a Three-Phase System, the formula is:

\frac{{\text{kW} \times 1000}}{{V \times \text{PF} \times \eta \times \sqrt{3}}}

Let’s consider a 240V 5 kW motor with a power factor (PF) of 0.8 and an efficiency rating (η) of 88%. The calculation will be:

\frac{{5 \, \text{kW} \times 1000}}{{240 \, \text{V} \times 0.8 \times 0.88 \times 1.73}} = 17.1 \, \text{amps}

This also means that the 5-kW motor has an FLA rating of 17.1 amps in a three-phase system.

If you need information on other full load amps values, refer to the single-phase and 3 phase amps chart for motors with a power factor of 0.8 and an efficiency rating of 0.88 below. This will help you select and design electrical systems to ensure efficient and safe operation.

Power Rating Estimated FLA (Single-Phase System)
Hp Rating Kilowatts (kW) 110V 220V 240V
0.5 0.37 4.8 amps 2.39 amps 2.19 amps
1 0.75 9.7 amps 4.84 amps 4.44 amps
2 1.49 19.2 amps 9.62 amps 8.82 amps
3 2.24 28.9 amps 14.46 amps 13.26 amps
5 3.73 48.2 amps 24.08 amps 22.1 amps
Power Rating Estimated FLA (Three-Phase System)
Hp Rating Kilowatts (kW) 230V 460V 575V
0.5 0.37 1.32 amps 0.66 amps 0.53 amps
1 0.75 2.68 amps 1.34 amps 1.10 amps
2 1.49 5.32 amps 2.66 amps 2.13 amps
3 2.24 8 amps 4 amps 3.20 amps
5 3.73 13.31 amps 6.66 amps 5.33 amps
7 5.22 18.63 amps 9.32 amps 7.45 amps
10 7.46 26.63 amps 13.32 amps 10.65 amps
15 11.19 39.95 amps 19.97 amps 15.98 amps

Factors Affecting Full Load Amps

Various factors can influence the Full Load Amperage (FLA) of electrical devices and motors. These factors include:

  • Voltage Rating: The voltage level supplied to the electrical device or motor directly affects its full load a Higher voltage ratings result in lower current draws, while lower voltage ratings lead to increased amp draws.
  • Power Rating (kW or Hp): The power rating, expressed in kilowatts (kW) or horsepower (Hp), is another influential factor in determining FLA. Motors with higher power ratings typically require higher amp draws to function optimally under full load conditions.
  • Power Factor: The power factor indicates the motor’s efficiency in converting electrical power into useful work. Motors with low power factors draw higher currents, increasing full load a
  • Efficiency Rating: The efficiency rating refers to the ratio of useful mechanical output power to the total electrical input power. Highly efficient motors convert more electrical power into mechanical work, leading to lower full load a


Understanding what is full load amps is essential for making informed decisions when selecting and designing motorized equipment circuits. It ensures safe and efficient electrical system operations.

Additionally, optimizing FLA can improve energy efficiency and cost savings, benefiting businesses and the environment.

However, aside from this current, considering the SF amps, which indicate a motor’s ability to handle temporary overloads without damage, is also essential. For optimal efficiency, seek a motor with a lower FLA and higher SF.

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