To improve power factor in an AC circuit with an inductive load, which approach is effective?

• A. Add inductors in series with the load
• B. Remove the load entirely
• C. Increase the supply voltage
• D. Add capacitors in parallel with the load to supply reactive VARs

Answer: (D)

Inductive loads make the current lag the voltage, which creates reactive power and reduces the power factor. The way to improve the power factor is to supply some of that reactive power locally with capacitors. When you connect capacitors in parallel with the load, they provide leading reactive current that cancels part of the lagging reactive current from the inductor. This reduces the net reactive power drawn from the source, which makes the current swing closer in phase to the voltage and pushes the power factor toward unity.

Adding inductors in series would increase the lagging effect, not help it. Removing the load defeats the purpose of the circuit. Simply increasing the supply voltage doesn’t address the phase difference between current and voltage. So, placing capacitors in parallel to supply reactive VARs is the effective method for improving the power factor.