TechTalkBlueA common question we often receive is “How much power do I need on the single phase side to adequately power my 3 phase motor?”

It’s a relatively simple calculation.

In operation, two single phase lines of current are distributed among three output lines of power from the phase 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 motor data plate. The resulting value is the amount of power, expressed in amps, required at the input side of phase converter.

Here’s a simple example of the equation:

You’re preparing to drive a three phase low-horsepower motor rated at 10 amps.

Single phase power 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 motor load, assuming the motor 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.

NAPCES offers a full line up of rotary, static and digital converters capable of single and 3 phase power. If you have questions regarding our available products, sizing, power or anything else we encourage you to contact our expertly trained associates for further assistance.