Calculator Inputs
The form uses a 3-column, 2-column, and 1-column responsive layout.
Example Data Table
| Load | Voltage | Frequency | Initial PF | Target PF | Phase | Connection | Required kVAR | Selected kVAR | Selected µF |
|---|---|---|---|---|---|---|---|---|---|
| 150.00 kW | 400.00 V | 50.00 Hz | 0.72 | 0.95 | Three Phase | Delta | 95.28 kVAR | 100.00 kVAR | 663.15 µF |
Formula Used
Q₁ = P × tan(acos(PF₁))
Q₂ = P × tan(acos(PF₂))
Qc = P × (tan φ₁ − tan φ₂)
S = P / PF
Three phase: I = P × 1000 / (√3 × V × PF)
Single phase: I = P × 1000 / (V × PF)
Single phase: C = Q / (2πfV²)
Three phase delta: C = Q / (3 × 2πfV²)
Three phase star: C = Q / (2πfV²)
In these formulas, P is active power in kW, Q is reactive power in VAR, V is voltage, f is frequency, and C is capacitance in farads.
How to Use This Calculator
- Enter the active load in kW.
- Enter system voltage and operating frequency.
- Provide the present power factor and your target power factor.
- Select single-phase or three-phase operation.
- Choose delta or star for three-phase capacitor placement.
- Enter the standard bank step if you want rounded sizing.
- Add a reactive demand charge rate to estimate savings.
- Press the calculate button to show the result above the form.
- Review exact kVAR, selected bank, capacitance, current reduction, and savings.
- Use the export buttons to save the report as CSV or PDF.
Key Output Tags
Required kVAR Selected Bank Size Capacitance in µF Apparent Power Reactive Power Line Current Change Monthly Savings Annual SavingsFAQs
1) What does this calculator find?
It estimates the capacitor bank size needed to raise power factor from the current value to a chosen target. It also shows capacitance, current reduction, apparent power change, and optional savings from reduced reactive demand charges.
2) Why is power factor correction important?
Poor power factor increases reactive current, raises line losses, and can trigger utility penalties. Correction reduces unnecessary current, improves system efficiency, releases capacity, and helps electrical equipment operate under a lighter reactive burden.
3) What is the difference between exact and selected bank size?
The exact value is the theoretical kVAR needed to hit the target. The selected value is the practical standard bank size after rounding by your chosen step, which better reflects real procurement and installation choices.
4) When should I use delta or star connection?
Use the connection that matches your design method and capacitor bank arrangement. Delta banks are common in three-phase applications. Star banks can also be used, but capacitance per phase differs because the phase voltage relationship changes.
5) Can this calculator be used for single-phase systems?
Yes. Choose single phase and the calculator switches to the proper current and capacitance formulas. It then treats the bank as a single-phase correction capacitor instead of a three-phase star or delta arrangement.
6) Why does the selected power factor exceed the target slightly?
That usually happens when the required kVAR is rounded upward to the next standard bank size. Standard capacitor banks are not infinitely adjustable, so the nearest practical selection can produce a slightly higher corrected value.
7) Are the savings results exact?
No. They are planning estimates based on the reactive demand rate you enter. Real savings depend on tariff structure, switching strategy, load variation, harmonics, utility rules, and how long the correction bank remains connected.
8) Should I install the calculated capacitor bank directly?
Use the result as a design guide, not a final protection study. Before installation, verify harmonics, switching duty, resonance risk, voltage rating, temperature limits, and local electrical code requirements with a qualified engineer.