What practical method is used to improve power factor in an inductive circuit?

What practical method is used to improve power factor in an inductive circuit?

• A. Connect a capacitor in parallel with the load
• B. Connect a resistor in series with the load
• C. Install a transformer in series
• D. Increase the supply voltage

Answer: (A)

To improve power factor in an inductive circuit, you need to supply leading reactive power to cancel part of the lag caused by the inductor. Connecting a capacitor in parallel with the load does this exactly: the capacitor provides current that leads the voltage, offsetting the lagging current from the inductive load. As the capacitor adds reactive power of the opposite sign, the overall current becomes more in phase with the voltage, boosting the power factor toward unity. The real power drawn by the load stays the same, but the apparent power drops because the reactive component is reduced. Why the other options don’t fit: placing a resistor in series adds more real power loss and doesn’t supply reactive power to counter the inductive lag, so the power factor doesn’t improve. Installing a transformer in series doesn’t address the reactive lag either. Increasing the supply voltage changes current magnitude but not the phase relationship, so it doesn’t meaningfully improve power factor.

To improve power factor in an inductive circuit, you need to supply leading reactive power to cancel part of the lag caused by the inductor. Connecting a capacitor in parallel with the load does this exactly: the capacitor provides current that leads the voltage, offsetting the lagging current from the inductive load. As the capacitor adds reactive power of the opposite sign, the overall current becomes more in phase with the voltage, boosting the power factor toward unity. The real power drawn by the load stays the same, but the apparent power drops because the reactive component is reduced.

Why the other options don’t fit: placing a resistor in series adds more real power loss and doesn’t supply reactive power to counter the inductive lag, so the power factor doesn’t improve. Installing a transformer in series doesn’t address the reactive lag either. Increasing the supply voltage changes current magnitude but not the phase relationship, so it doesn’t meaningfully improve power factor.