Power Factor Calculator
Real Power (W)
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Apparent Power (VA)
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Reactive Power (VAR)
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Phase Angle
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Understanding Power Factor in AC Circuits
Power factor is ratio of real power (W) to apparent power (VA). Ranges 0-1. PF of 0.85 means 85% does useful work.
Apparent power = V x I. Real power = VA x PF. Reactive power = VA x sin(angle). These form the power triangle.
Low PF wastes utility capacity. Motors and transformers cause low PF. Correction uses capacitor banks.
Frequently Asked Questions
Good power factor?
0.95 or higher. Utilities penalize below 0.85-0.90. Unity (1.0) is ideal.
What causes low PF?
Inductive loads: motors, transformers, fluorescent ballasts. Large motors at partial load are worst.
How to correct PF?
Add capacitor banks in parallel with inductive loads. Automatic systems switch capacitors as needed.
kW vs kVA?
kW is real power (does work). kVA is apparent power (includes reactive). kW = kVA x PF.