Calculator Inputs
Example Data Table
| Load | Phase | kW | PF | kVAR | kVA | Voltage (V) | Current (A) | Capacitor kVAR |
|---|---|---|---|---|---|---|---|---|
| Motor Panel | Three Phase | 75.00 | 0.80 | 56.25 | 93.75 | 415 | 130.43 | 28.47 |
| Chiller Feed | Three Phase | 120.00 | 0.82 | 83.91 | 146.34 | 400 | 211.22 | 52.45 |
| Lighting Bus | Single Phase | 12.00 | 0.95 | 3.94 | 12.63 | 230 | 54.91 | 5.18 |
| Compressor | Three Phase | 90.00 | 0.76 | 76.77 | 118.42 | 440 | 155.39 | 31.54 |
Formula Used
kVAR = kW × tan(cos-1(PF))
kVAR = kVA × √(1 − PF²)
Single phase: kVAR = (V × I × sinφ) / 1000
Three phase: kVAR = (√3 × V × I × sinφ) / 1000
Capacitor kVAR = kW × [tan(cos-1(Initial PF)) − tan(cos-1(Target PF))]
kVA = √(kW² + kVAR²)
Single phase: I = (kVA × 1000) / V
Three phase: I = (kVA × 1000) / (√3 × V)
How to Use This Calculator
- Select the calculation mode that matches your available electrical data.
- Choose single phase or three phase operation.
- Enter known values such as kW, kVA, power factor, voltage, current, or angle.
- Provide initial and target power factor values to estimate capacitor correction needs.
- Enter supply frequency and system label for cleaner reporting.
- Press Calculate to show results above the form.
- Review kVAR, kVA, current, correction size, and the graph.
- Use the CSV and PDF buttons to export the result summary.
FAQs
1. What does kVAR mean in an electrical system?
kVAR measures reactive power. It represents energy that moves between source and reactive loads like motors, transformers, and inductive equipment without producing useful mechanical work.
2. Why is reactive power important?
Reactive power affects current flow, voltage regulation, and equipment loading. High reactive demand raises line current and can reduce usable capacity in cables, generators, and transformers.
3. How does poor power factor affect operations?
Poor power factor increases apparent power and current for the same real load. That can raise losses, reduce available capacity, and sometimes trigger utility penalties.
4. When should I use the kW and PF mode?
Use that mode when real power and operating power factor are already known from metering, design sheets, or motor load studies.
5. What is the capacitor kVAR result used for?
It estimates the reactive compensation needed to move from an initial power factor to a target power factor. This helps size capacitor banks for correction.
6. Does single phase or three phase selection matter?
Yes. Three phase systems use a different current and reactive power relationship. Selecting the correct phase type improves kVAR, kVA, and current calculations.
7. Can this calculator estimate capacitance too?
Yes. It estimates microfarads from capacitor kVAR, voltage, frequency, and phase type. This is a planning value and should be verified before procurement.
8. Is this calculator suitable for capacitor bank planning?
It is useful for preliminary sizing, comparison, and reporting. Final selection should still consider harmonics, detuning, switching steps, tolerance, and site conditions.