Formula and Method
DC: I = P / V. Single-phase: I = P / (V x PF). Three-phase: I = P / (sqrt(3) x V x PF). Efficiency is applied when entered below 100%.
Assumptions
- Balanced three-phase load
- Power factor applies to AC systems only
- Efficiency is treated as input-side correction
Important Warnings
- Use nameplate data when available.
- Nonlinear loads, harmonics, and starting current are not included.
FAQ
What is the difference between kW and kVA?
kW is real power. kVA is apparent power. For AC systems, kW = kVA x power factor.
Can I use this for motors?
Yes for a first estimate, but the motor current calculator is better because it includes efficiency and overload context.