Red Seal Electrician Practice
Power factor and three-phaseQuestion 1218 of 1506

The line voltage sags. How does a synchronous condenser help restore it?

  1. It draws lagging current, which lowers generator excitation.
  2. It draws leading current, which raises generator excitation.
  3. It disconnects from the line until the voltage returns.
  4. It switches in a fixed capacitor step.
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Correct answer: It draws leading current, which raises generator excitation.

The leading current increases generator excitation, which pushes the line voltage back up. A capacitor bank cannot do this.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 13.3: Synchronous Condenser

Practice power factor and three-phase

Questions last reviewed: 18 October 2026