Size the capacitor bank needed to improve power factor and cut current.
Calculate the capacitor bank (kVAr) needed to improve power factor, and the resulting current reduction.
Inductive loads such as motors and transformers draw reactive power (kVAr) that does no useful work but still loads the supply. Adding a capacitor bank supplies that reactive power locally, raising the power factor towards unity. This reduces the current drawn, frees up cable and transformer capacity, and cuts the reactive-power charges that suppliers apply to larger installations.
The required capacitor size is the difference between the present and target reactive power: Qc = P × (tan φ₁ − tan φ₂). Target 0.95–0.98 — going higher risks a leading power factor.
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