3 phase power calculator
Compute 3-phase real power (kW), apparent (kVA), and reactive (kVAr) using √3·V·I and power factor. Supports line voltage/current and balanced loads.
industrial load kW
For three phase balanced Load use P(kw) = √3 Vl(V) Il(A)pf / 1000 & S(kva) = √3 Vl Il / 1000. Reactive power is Q(kVAr) = P/tan – model(arccos(PF)).
Formula & Table Summary:
- S (VA): √3 x VL x IL
- P (W): √3 x VL x IL x PF
- Q (VAr): √3 x VL x IL x sinφ where φ = arccos(PF)
- k-units: divide by 1000
- Alt: Q (kVAr) = P (kW) x tan(arccos(PF))
400V 3 phase kW; 415V 3 phase kW
The 3 Phase Power Calculator finds the real power (kW), apparent power (kVA), and reactive power (kVAr) of three-phased, balanced systems. To immediately obtain results, enter line-to-line voltage (V L ), line current (I L ),, and the power factor (PF). By definition, the apparent power is S = 1/2 3 VL IL. Real power gets power factor: P = 1/2 3 VL IL PF. The reactive power is obtained as a consequence of the phase angle 4: Q = 3-vector-root-of-3-times-V_L-times-I_L-times-sin4 (replacing the factor of sin4 by PF, the result is Q = P times tan (arccos (PF)). The results can be indicated in kW/ kVA/ kVAr after division by 1000. These formulae are used in motors, HVAC equipment, switchboards, and distribution feeders on a 3-phase network (e.g,. 208V, 400/415V, 480V). Use them to size conductors, breakers, transformers, or check nameplate ratings and energy demand. The calculator uses balanced loads, single-phase calculations may be used with single-phase or unbalanced systems, and adds the answers.
three-phase power calculator
| V_L (V) | I_L (A) | PF | S (kVA) | P (kW) | Q (kVAr) |
|---|---|---|---|---|---|
| 400 | 50 | 0.85 | 34.64 | 29.45 | 18.56 |
| 415 | 80 | 0.90 | 57.49 | 51.74 | 24.92 |
| 480 | 100 | 0.80 | 83.14 | 66.51 | 49.89 |
Frequently Asked Questions - 3 phase power calculator:
What is the 3-phase power formula for kW?
P(kW)=√3·V_L(V)·I_L(A)·PF/1000.
How do I get kVA from voltage and current?
S(kVA)=√3·V_L·I_L/1000 for balanced loads.
How is reactive power calculated?
Q(kVAr)=P·tan(arccos(PF)) or √3·V_L·I_L·sinφ/1000.
What voltage should I use?
Use line-to-line voltage (e.g., 400/415/480 V) for the √3 formulas.
Does frequency affect the formula?
No, not directly. Frequency affects equipment behavior but not the algebra here.
Can I use these for unbalanced loads?
Compute per phase and sum P, Q, and S. These closed forms assume balance.
How do I improve PF?
Add capacitors/VFDs to reduce reactive power and current draw.
What’s the relation between kW, kVA, and PF?
PF=P/S, with P in kW and S in kVA.
How do I find current from kW?
I_L= P(kW)·1000 /(√3·V_L·PF).
Is motor efficiency part of PF?
No. Efficiency links mechanical kW to electrical kW; PF links kW to kVA.
