Power Factor Calculator
Calculate power factor, phase angle, and power triangle relationships in AC circuits
Calculate Power Factor
Active power that performs real work
Power stored in reactive components
Total power supplied to circuit
Power Factor Results
Real Power (P)
Active power doing work
Reactive Power (Q)
Power in reactive elements
Apparent Power (S)
Total power supplied
Power Factor Classification
Very poor efficiency, power factor correction required.
Power Triangle Formula: S² = P² + Q²
Power Factor: PF = P / S = cos(φ)
Impedance Triangle: Z² = R² + X²
Power Factor Analysis
Example Calculation
Industrial Motor Example
Real Power (P): 8,000 W
Reactive Power (Q): 6,000 VAR
Motor Load: Inductive (lagging power factor)
Calculation
S = √(P² + Q²) = √(8000² + 6000²)
S = √(64,000,000 + 36,000,000) = 10,000 VA
Power Factor = P / S = 8000 / 10000 = 0.8
Phase Angle φ = arccos(0.8) = 36.87°
Result: 80% efficiency, 0.8 lagging power factor
Power Factor Types
Lagging PF
Inductive loads (motors, transformers)
Current lags voltage
Leading PF
Capacitive loads
Current leads voltage
Unity PF
Pure resistive loads
Current in phase with voltage
PF Classification
Power Factor Tips
Higher power factor means better energy efficiency
Poor PF can result in utility penalty charges
Use capacitors to correct lagging power factor
Monitor PF regularly in industrial settings
Understanding Power Factor in AC Circuits
What is Power Factor?
Power factor is the ratio of real power (P) to apparent power (S) in an AC circuit. It represents how effectively electrical power is being used. A power factor of 1 (or 100%) means all the power is being used effectively, while a lower power factor indicates energy is being wasted.
Power Triangle
- •Real Power (P): Power that performs useful work (watts)
- •Reactive Power (Q): Power stored in reactive components (VAR)
- •Apparent Power (S): Total power supplied to circuit (VA)
Key Formulas
Power Factor = P / S = cos(φ)
S² = P² + Q²
Z² = R² + X²
S = V × I (apparent power)
Why It Matters
- Energy Efficiency: Higher PF = less energy waste
- Cost Savings: Avoid utility penalty charges
- Equipment Life: Reduced stress on electrical systems
- Capacity: More real power for same electrical infrastructure
Power Factor Correction
Power factor correction involves adding capacitors or inductors to counteract reactive power:
- •Add capacitors for inductive (lagging) loads
- •Add inductors for capacitive (leading) loads
- •Target power factor of 0.95 or higher
Common Applications
- Industrial Motors: Typically 0.7-0.85 lagging
- Fluorescent Lighting: Often requires correction
- Welding Equipment: Poor power factor loads
- Power Supplies: Switching supplies can have low PF
- Transformers: Contribute to reactive power