Watt Ke Ampere 3 Phase

4 min read Jun 26, 2024
Watt Ke Ampere 3 Phase

Watt to Ampere Conversion for 3-Phase Systems

Understanding the Basics

When working with electrical systems, it's essential to understand the relationship between watts (W), volts (V), and amperes (A). This article will focus on converting watts to amperes for 3-phase systems, but first, let's review the basics:

  • Watt (W): A unit of power, measuring the rate of energy transfer.
  • Volt (V): A unit of voltage, measuring the potential difference between two points.
  • Ampere (A): A unit of current, measuring the flow of electrical charge.

3-Phase Systems

In a 3-phase system, three conductors carry alternating currents that are out of phase with each other by 120 electrical degrees. This type of system is commonly used in industrial and commercial settings due to its higher power density and efficiency compared to single-phase systems.

Watt to Ampere Conversion Formula for 3-Phase

To convert watts to amperes for a 3-phase system, you can use the following formula:

I (A) = P (W) / (√3 * V (V) * PF)


  • I (A): The root mean square (RMS) current in amperes
  • P (W): The total power in watts
  • V (V): The line-to-line voltage in volts
  • PF: The power factor (typically 0.8 for industrial loads and 0.9 for commercial loads)
  • √3: The square root of 3, approximately equal to 1.732

Example Calculation

Let's say you have a 3-phase motor with a power rating of 10 kW and a line-to-line voltage of 415 V. The power factor is 0.85.

Given values:

  • P (W) = 10,000 W
  • V (V) = 415 V
  • PF = 0.85


I (A) = 10,000 W / (√3 * 415 V * 0.85) ≈ 14.15 A

Therefore, the current drawn by the motor is approximately 14.15 amperes.

Important Considerations

When converting watts to amperes for 3-phase systems, it's essential to consider the following:

  • Line-to-line voltage: The voltage between any two phases, not the phase-to-neutral voltage.
  • Power factor: The ratio of real power to apparent power, which affects the calculation.
  • Conductor sizing: Ensure the conductors are sized correctly to handle the calculated current.


Converting watts to amperes for 3-phase systems is a crucial calculation in electrical engineering. By understanding the formula and considering the important factors, you can accurately determine the current drawn by a 3-phase load. Remember to use the correct values for line-to-line voltage and power factor to ensure accurate results.

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