Formula and Method
For kW input, I = kW x 1000 / (sqrt(3) x V x PF x efficiency). For kVA input, I = kVA x 1000 / (sqrt(3) x V).
Assumptions
- Balanced three-phase load
- Line-to-line voltage input
Important Warnings
- Starting current and harmonics are not included.
- Use actual equipment nameplate data for final selection.
FAQ
Should I enter phase voltage or line voltage?
Enter line-to-line voltage, such as 400 V, 480 V, or 690 V.
Why is power factor ignored for kVA?
kVA is apparent power, so current can be calculated directly from apparent power and voltage.