Power factor (cos φ)
Arbeidsfactor (cos φ)
Also known as: energieopslag, cos-phi, power-factor, pf, arbeidsfactor, frequentie, condensator, condensatoren, capacitor, vermogensfactor, condensatorbank, capacitor-bank, pfc, netfrequentie, mains-frequency, ontlaadtijd, discharge-time, dc-bus, capacitor-discharge, vfd-discharge, ups-discharge
Ratio of active power P to apparent power S = U×I; cos φ = P/S. Inductive loads (motors, old TL) draw extra reactive current (cos φ < 1), requiring larger conductor cross-sections for the same useful kW. Modern LED, IT loads, and inverters have PFC and are ≥ 0.95.
Practical example
Power factor (cos φ): A 4 kW motor with cos φ = 0.8 at 230 V draws I = 4000 / (230 × 0.8) ≈ 21.7 A — select a 25 A circuit, not the naive 4000/230 ≈ 17.4 A.
Common mistake
Power factor (cos φ). Common mistake: Sizing cable cross-section and circuit breaker based on useful power in kW without including cos φ — for inductive loads, actual current is higher than naive calculation suggests.
See also
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