Formula to Calculate Current in 3 Phase circuits when watts or HP is known [With Examples]

In this post, you’ll learn the basic formula to calculate current in 3 phase circuits when either of the watts, kilowatts, or horsepower is known. Let’s first check the formulas:

Let’s solve some examples to better understand them.

Formula to calculate current in 3 phase circuit from watts

Find the current which will flow through the circuit which has a 1000 watt load at the power factor of 90%. The operating source is 3 phase at 400 V.
From: I = P / (E * PF * 1.73) = 1000 watt / (400 * 1.73 * 0.9) = 1.60 A

Formula to calculate current in 3 phase circuit from kilowatts

Here is formula is similar as we did it previously, just the factor 1000 is multiplied in this case.

When HP is known

Determine the amperage loads of a 2 HP, 3 phase motor at the power factor of 85% whose rated efficiency is 90%. The voltages are 230.
From: I = (HP * 746) / (E * PF * Efficiency * 1.73) = 0.483 A

So that was all about 3 phase current calculations.

You can learn the calculation for single phase here.

One thought on “Formula to Calculate Current in 3 Phase circuits when watts or HP is known [With Examples]

  • March 20, 2018 at 7:49 pm
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    How to download videos?

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