ClueLuma

Capacitor reactive compensation calculator

Capacitor rating is calculated as P × (sqrt(1−PF1^2)/PF1 − sqrt(1−PF2^2)/PF2). Use the stated system boundary and matching input units.

QC=P×(1−PF12PF1−1−PF22PF2)Q_{C} = P \times \left(\frac{\sqrt{1 - \mathrm{PF}_{1}^{2}}}{\mathrm{PF}_{1}} - \frac{\sqrt{1 - \mathrm{PF}_{2}^{2}}}{\mathrm{PF}_{2}}\right)

Calculator

Enter the values you know and leave one box empty. Calculate finds the empty one, the result or any input.

kW
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—
kVAR

Worked example

Given

  • PP = 500 kW
  • PF1\mathrm{PF}_{1} = 0.75 —
  • PF2\mathrm{PF}_{2} = 0.95 —
QC=500×(1−0.7520.75−1−0.9520.95)≈276.6Q_{C} = 500 \times \left(\frac{\sqrt{1 - {0.75}^{2}}}{0.75} - \frac{\sqrt{1 - {0.95}^{2}}}{0.95}\right) \approx 276.6

Symbols and units

SymbolMeaningUnit
QCQ_{C}capacitor ratingkVAR
PPreal demandkW
PF1\mathrm{PF}_{1}initial power factor—
PF2\mathrm{PF}_{2}target power factor—

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Results are estimates for study and screening. Check the inputs, units and assumptions before you use them for design, billing or contract decisions.