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Home Electrical Engineering Three-Phase Systems in Power Applications Comments

  • Question
  • A three-phase generator is connected to three 90 Ω load resistors. Each coil generates 120 V ac. A common neutral line exists. How much current flows through the common neutral line?


  • Options
  • A. 0 A
  • B. 1.33 A
  • C. 3.99 A
  • D. 2.66 A

  • Correct Answer
  • 0 A 


  • Three-Phase Systems in Power Applications problems


    Search Results


    • 1. In a Y-Y source/load configuration, the

    • Options
    • A. phase current, the line current, and the load current are all equal in each phase
    • B. phase current, the line current, and the load current are 120° out of phase
    • C. phase current and the line current are in phase, and both are 120° out of phase with the load current
    • D. line current and the load current are in phase, and both are out of phase with the phase current
    • Discuss
    • 2. Compare the total copper cross sections in terms of current-carrying capacity for a single-phase and a three-phase 120 V system with effective load resistance of 15 Ω.

    • Options
    • A. single-phase 32 A; three-phase 16 A
    • B. single-phase 16 A; three-phase 8 A
    • C. single-phase 8 A; three-phase 4 A
    • D. single-phase 16 A; three-phase 0 A
    • Discuss
    • 3. A single-phase sinusoidal voltage of 120 V is connected to a 90 Ω load. Current in the circuit is

    • Options
    • A. 13.3 mA
    • B. 133 mA
    • C. 1.33 A
    • D. 6.2 A
    • Discuss
    • 4. A constant load power means a uniform conversion of

    • Options
    • A. mechanical to electrical energy
    • B. electrical to mechanical energy
    • C. current to voltage
    • D. voltage to current
    • Discuss
    • 5. In a △-connected source driving a △-connected load, the

    • Options
    • A. load voltage and line voltage are one-third the source voltage for a given phase
    • B. load voltage and line voltage are two-thirds the source voltage for a given phase
    • C. load voltage and line voltage cancel for a given phase
    • D. load voltage, line voltage, and source phase voltage are all equal for a given phase
    • Discuss
    • 6. A two-phase generator is connected to two 90 Ω load resistors. Each coil generates 120 V ac. A common neutral line exists. How much current flows through the common neutral line?

    • Options
    • A. 1.33 A
    • B. 1.88 A
    • C. 2.66 A
    • D. 1.77 A
    • Discuss
    • 7. In a certain Y-Y system, the source phase currents each have a magnitude of 9 A. The magnitude of each load current for a balanced load condition is

    • Options
    • A. 3 A
    • B. 6 A
    • C. 9 A
    • D. 27 A
    • Discuss
    • 8. In a three-phase system, the voltages are separated by

    • Options
    • A. 45°
    • B. 90°
    • C. 120°
    • D. 180°
    • Discuss
    • 9. In a Y-connected circuit, between each line voltage and the nearest phase voltage, there is a phase angle of

    • Options
    • A. 0°
    • B. 30°
    • C. 60°
    • D. 120°
    • Discuss
    • 10. In a Y-connected source feeding a △-connected load,

    • Options
    • A. each phase of the load has one-third of the full line voltage across it
    • B. each phase of the load has two-thirds of the full line voltage across it
    • C. each phase of the load has the full line voltage across it
    • D. each phase of the load has a voltage across it equal to
    • Discuss


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