Analisis Kompensasi Daya Reaktif terhadap Faktor Daya Motor Induksi Menggunakan Bank Kapasitor

Abstract

Induction motors are the most widely used electrical machines in industry and are classified as inductive loads that absorb significant reactive power, resulting in a low power factor. A low power factor increases line current, causes greater distribution losses, and may incur penalty charges from utility companies. This study experimentally analyzes the effect of a switchable capacitor bank on the power factor and line current of a three-phase slip-ring induction motor under three loading conditions (M = 1.6 Nm, 1.8 Nm, and 2 Nm) at a supply voltage of 380 V / 50 Hz. Eight capacitor bank switching levels ranging from 0 to 1,350 VAR were tested. The results show that the power factor improved significantly from 0.23–0.28 (no compensation) to 0.53–0.55 at the optimal level (1+2+3+4), while the line current decreased by up to 53% from 1.57–1.72 A to 0.73–0.82 A. The motor current remained unaffected by compensation, confirming that capacitive compensation only reduces reactive current on the supply side. Over-compensation was also observed when excessive capacitance was applied, causing the power factor to deteriorate. These findings confirm that proper capacitor bank sizing is critical and must match the reactive power demand at each load condition.