Why Correction Matters
A three phase load often draws active and reactive power. Active power performs useful work. Reactive power supports magnetic fields in motors, transformers, and welders. A low power factor makes current higher than needed. Higher current raises cable losses, transformer loading, voltage drop, and possible utility charges.
What The Calculator Checks
This calculator sizes a capacitor bank for a balanced three phase system. It compares present power factor with the target value. It then finds the reactive power that must be supplied locally. You can enter real power directly. You can also estimate it from measured line current, voltage, and power factor. The tool also estimates corrected current, released kVA capacity, bank capacitance, and feeder loss savings.
Practical Design Notes
Power factor correction should not be chosen by guesswork. Oversized capacitors can push the system into a leading condition. That may raise voltage and cause nuisance trips. Harmonics can also stress capacitors. Drives, rectifiers, welders, and office electronics may need detuned reactors. A site survey is best for large installations. Use measured demand data when possible.
Cost And Energy Impact
Capacitors do not normally reduce active energy used by the load. A motor doing the same job still needs similar kWh. Savings come from lower line current, lower I squared R loss, reduced demand penalties, and better transformer use. This page includes a feeder resistance option. It estimates only conductor loss savings from current reduction. Utility billing rules may create additional savings.
Safe Use
Treat the result as an engineering estimate. Check local codes, switchgear ratings, short circuit capacity, fuse size, discharge resistors, and ventilation. Capacitor banks must be rated for voltage and duty. Automatic banks should use steps that match changing load. Fixed banks suit constant loads. Confirm final values with a qualified electrical professional before purchase or installation.
Reading The Outputs
The ideal kVAR is the theoretical correction size. The selected kVAR includes safety allowance and step rounding. Current reduction shows how much line current falls after correction. Capacitance values help compare delta and star banks. Loss savings depend strongly on cable resistance and operating hours. Review every warning before using the final bank rating in design work. Document assumptions for future maintenance and audits.