🌀 เครื่องคำนวณการแก้ตัวประกอบกำลัง

Required kVAR = kW x (tan(acos(pf1)) - tan(acos(pf2))). To correct 300 kW from 0.8 to 0.95: 300 x (0.75 - 0.33) = 126 kVAR, so select a 150 kVAR bank. The calculator computes the kVAR and picks the next standard bank size.

Low Power Factor means higher current for the same real power, so the utility needs larger conductors and transformers and suffers higher losses. Most utilities require 0.9-0.95 and add a penalty or demand charge below ~0.9. Correcting to 0.95 typically cuts the reactive current 40-60%. The calculator shows the kVAR needed.

Lagging power factor means the load is inductive (motors, transformers) and current lags voltage. Leading power factor means capacitive (over-compensation). Over-compensating past unity creates a leading pf that can cause overvoltage and resonance. Target 0.95 lagging, not unity; the calculator avoids over-correction.

Fixed banks suit steady loads; automatic (switched) banks step capacitors in and out to follow varying load and avoid over-compensation at light load. For a plant whose load swings 30-100%, use an automatic bank. The calculator sizes the bank; larger variable loads recommend switched stages.

Correcting power factor reduces reactive current and often removes a penalty charge (typically 0.5-3% of the bill per 0.01 below 0.9). For a plant with a $120,000/yr bill at 0.78 pf, correction to 0.95 can save $2,000-6,000/yr. The calculator quantifies the kVAR and the bill impact.