A simple question that we often receive at Prudent Devices is “How much power do I need on the single phase side to adequately power my 3 phase Equipment Or What is the Single phase Current Load of a given 3 phase Number. ?”

It’s actually very easy to make 3 phase power calculations.

In a situation of current supply operation, two single-phase lines of current are distributed among three output lines of power from the phase distributor or converter. To calculate what input power is needed, the square root of three (1.732) is used as a multiplier of the three-phase current value found on the equipment sheet.

The outcome value is the value of power, expressed in AMPs required at the input side of the phase converter.

Here’s a simple example of the equation:

We’re Switching on to drive a three-phase Equipment rated at 10 amps.

Single phase to 3 phase power calculation input requirement = The square root of 3 (1.732) x 10 amps

= 1.732 x 10 amps

= 17.32 Amps

Single phase power input in this instance is 17.32 Amps

The total load draw should not be any higher than the rated Equipment load, assuming the Equipment is appropriately rated for the work to be performed.

Note: The size, type, and style of the phase converter have no impact upon the input current required to drive the motor load