Power Factor
Power Factor (PF) is the dimensionless ratio of real power (kW) to apparent power (kVA), expressed as PF = kW/kVA or cos(θ), where θ is the phase angle between voltage and current. A PF of 1.0 (unity) is ideal, indicating all supplied power performs work; values below 0.8 are undesirable and typically require correction.
In shop floor maintenance, PF is tracked as a key electrical asset health metric for motors, transformers, and HVAC systems using CMMS like ServiceGrid to schedule Power Factor Correction (PFC) via capacitor banks. Maintenance teams use real-time PF monitoring via smart sensors for condition-based maintenance of induction motors, detecting under-load faults or winding degradation. PF data triggers alerts for energy demand charge reduction and prevents utility penalties for low PF (<0.9). PFC systems, such as automatic APFC panels, are maintained to ensure PF stays ≥0.9, avoiding uncontrolled stages (<0.8) that cause voltage instability.
How does PF differ in non-linear vs. linear loads?
Linear loads have PF = cos(θ) (displacement PF); non-linear loads have True PF = Displacement PF × Distortion PF (k_d × k_φ), where distortion PF <1 due to harmonics.
Why is lagging PF inductively bad, leading PF capacitively bad?
Lagging PF (inductive) consumes reactive power (Q > 0), increasing current and losses; leading PF (capacitive) supplies reactive power (Q < 0), risking overvoltage and resonance.
What PF threshold triggers PFC in industrial plants?
PF < 0.8 requires immediate correction; optimal target is 0.95–0.97 for maximum benefit without resonance risk.