Capacitor banks or active filters installed in elevator electrical systems to improve the power factor, reducing reactive power demand and utility charges.
Full Definition
Elevator drive systems, particularly older induction motor systems without VFDs, can have a poor power factor (below 0.85) because the inductive motor draws reactive current that does not perform useful work. Power factor correction (PFC) adds capacitor banks at the motor terminals or distribution board to supply reactive current locally, reducing the reactive component drawn from the utility supply. This lowers the kVA demand charge on the building's electricity bill and reduces distribution losses. Modern VFD-equipped elevators inherently have better power factor due to the DC link in the drive, and active front-end (AFE) drives can achieve unity power factor (1.0). PFC is measured as cos φ (cosine of the phase angle between voltage and current) and EN 50160 provides guidance on power quality in European installations.
