Power Factor Correction with Capacitor Banks
The Capacitor Sizing Calculator determines kVAR needed to improve power factor and reduce utility penalties.
Formula
kVAR = P × (tan(θ₁) - tan(θ₂))
Where θ = cos⁻¹(PF)
For 3φ: kVAR = √3 × V × I × (1 - PF)
kVAR Multiplier Table
| Existing PF | 0.70 | 0.75 | 0.80 | 0.85 | 0.90 |
|---|---|---|---|---|---|
| Target 0.95 | 0.583 | 0.485 | 0.398 | 0.317 | 0.233 |
| Target 0.98 | 0.749 | 0.651 | 0.564 | 0.483 | 0.399 |
Multiply kW × factor = kVAR needed
Benefits of PF Correction
- Lower kVA demand
- Reduced I²R losses
- Avoid utility PF penalties
- Improved voltage regulation
Examples
- 100 kW, PF 0.8 → 0.95 → 39.8 kVAR
- 500 kW, PF 0.75 → 0.98 → 325.5 kVAR
Installation Tips
- Use automatic PF controllers
- Avoid over-correction (>0.99)
- Derate for harmonics
- Check resonance risk
Common Mistakes
- Using kVA instead of kW
- Ignoring voltage rating
- Single-phase calc for 3φ
- No harmonic filter
Conclusion
Proper capacitor sizing saves energy and avoids penalties. Use with Power Factor and Energy Cost tools.