Red Seal Electrician Practice
Power factor and three-phaseQuestion 1026 of 1506

For a phase sequence detector made of two lamps and a capacitor, how is the capacitor sized?

  1. Its reactance is close to each lamp's resistance
  2. Its reactance is ten times each lamp's resistance
  3. Its reactance is zero, so it acts as a short circuit
  4. Its microfarad value matches the lamp wattage
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Correct answer: Its reactance is close to each lamp's resistance

Matching values keeps the circuit near balance so that the phase shift decides the lamp brightness.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 7.3: Phase Rotation

Practice power factor and three-phase

Questions last reviewed: 18 October 2026