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Home ‣ Electrical Engineering ‣ Three-Phase Systems in Power Applications See What Others Are Saying!
  • Question

  • A three-phase △-connected generator is driving a balanced load such that each phase current is 12 A in magnitude. When I ?a = 12 ∠30° A, what are the polar expressions for the other phase currents?


  • Options
  • A. I ?b = 12 ∠150° A, I ?c = 12∠?90° A
  • B. I ?b = 12∠120° A, I ?c = 12∠30° A
  • C. I ?b = 12∠30° A, I ?c = 12∠120° A
  • D. I ?b = 12∠90° A, I ?c = 12∠90° A

  • Correct Answer
  • I ?b = 12 ∠150° A, I ?c = 12∠?90° A 

    • More questions

    • 1. When the current through a 12 kΩ resistor is 8 mA, the power is

    • Options
    • A. 7.68 mW
    • B. 768 mW
    • C. 7.68 W
    • D. 76.8 W
      • Discuss
    • 2. In an RL circuit, part of the power is resistive and part is reactive.

    • Options
    • A. True
    • B. False
      • Discuss
    • 3. The inductance of an iron-core coil decreases if

    • Options
    • A. the number of turns is decreased
    • B. the iron core is removed
    • C. the length of the coil decreases
    • D. none of the above
      • Discuss
    • 4. A transformer with a 110 V primary has a 15:1 turns ratio. The load resistance, RL, is 120 Ω. What is the approximate voltage across the load?

    • Options
    • A. 7.3 V
    • B. 73 V
    • C. 88 V
    • D. 880 V
      • Discuss
    • 5. A 220 Ω resistor is in series with a 2.2 µF capacitor. The time constant is

    • Options
    • A. 48 µs
    • B. 480 µs
    • C. 2.42 µs
    • D. 24 µs
      • Discuss
    • 6. Find the Thevenin equivalent (VTH and RTH) between terminals A and B of the circuit given.


    • Options
    • A. 562 mV, 167 Ω
    • B. 5.62 V, 167 Ω
    • C. 5.62 V, 188 Ω
    • D. 562 mV, 188 Ω
      • Discuss
    • 7. Referring to Problem 15, if the input voltage is a 6 V sine wave with a dc level of 10 V, what is the output voltage magnitude?

    • Options
    • A. 6 V
    • B. 597 mV
    • C. 5.97 V
    • D. 0 V
      • Discuss
    • 8. The minimum resistance value for a blue, gray, red, silver resistor is

    • Options
    • A. 612 Ω
    • B. 6,120 Ω
    • C. 6,800 Ω
    • D. 6,460 Ω
      • Discuss
    • 9. Four 8 Ω speakers are connected in parallel to the output of an audio amplifier. If the maximum voltage to the speakers is 12 V, the amplifier must be able to deliver to the speakers

    • Options
    • A. 18 W
    • B. 1.5 W
    • C. 48 W
    • D. 72 W
      • Discuss
    • 10. Referring to circuit given, if R1 is changed to a 68 Ω resistor, what will be the current through it?


    • Options
    • A. 0.16 A
    • B. 0.24 A
    • C. 0.2 A
    • D. 0.04 A
      • Discuss

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