logo

CuriousTab

CuriousTab

Discussion

Home ‣ Electronics and Communication Engineering ‣ Power Electronics Comments
  • Question

  • A single phase half wave rectifier is feeding a resistive load. When a = 0, dc output voltage is 127 V. When a = 30°, the dc output voltage will be about


  • Options
  • A. 127 V
  • B. 120 V
  • C. 110 V
  • D. 100 V

  • Correct Answer
  • 120 V 

    Explanation
    Using Eq A single phase half wave rectifier is feeding a resistive load. When a = 0, dc output voltage is 127

    A single phase half wave rectifier is feeding a resistive load. When a = 0, dc output voltage is 127 = 0.933.

    Hence Vdc for 30° firing angle = 0.933 x 127 = ? 120 V.

    Power Electronics problems

    Search Results

    • 1. An electric heater is controlled by thyristors through on-off control. If a = 0.4, the heating is

    • Options
    • A. 16% maximum
    • B. 40% of maximum
    • C. 60% of maximum
    • D. 84% of maximum
      • Discuss
    • 2. The value of capacitor C for dynamic equalising circuit of series connected thyristors is determined by

    • Options
    • A. forward characteristics of thyristors
    • B. reverse recovery characteristics of thyristors
    • C. both forward and reverse recovery characteristics of thyristors
    • D. none of the above
      • Discuss
    • 3. In a multiphase chopper, all choppers operate together.

    • Options
    • A. True
    • B. False
      • Discuss
    • 4. A thyristor has a turn on time of 6 ?s. If the anode circuit is inductive, the turn on time will be

    • Options
    • A. 6 ?s
    • B. less than 6?s
    • C. more than 6 ?s
    • D. either 6 ?s or less
      • Discuss
    • 5. A single phase half wave controlled rectifier circuit has a free wheeling diode. The load is a combination of R and L. The firing angle is a. The period of conduction of SCR and free wheeling diode respectively are

    • Options
    • A. a < ?t < p and p < ?t < (2p + a)
    • B. a < ?t < p and p < ?t < 2p
    • C. a < ?t < (p + a) and (p + a) < ?t < 2p
    • D. a < ?t < p and p < ?t < (2p - a)
      • Discuss
    • 6. A 3 kV circuit uses SCR of 800 V rating. If derating is 25%, the number of SCRs in series is

    • Options
    • A. 4
    • B. 5
    • C. 6
    • D. 8
      • Discuss
    • 7. The terminals of a power MOSFET are called

    • Options
    • A. emitter, base, collector
    • B. source, gate, drain
    • C. source, base, drain
    • D. emitter, gate, drain
      • Discuss
    • 8. In a 3 phase fully controlled converter the firing frequency is

    • Options
    • A. 3 times the line frequency
    • B. 6 times the line frequency
    • C. 9 times the line frequency
    • D. 12 times the line frequency
      • Discuss
    • 9. In a single phase full wave regulator, the firing angles in the positive and negative half cycles are generally

    • Options
    • A. equal
    • B. different
    • C. equal or different
    • D. different but sometimes equal
      • Discuss
    • 10. The dynamic equalising circuit consists of a series combination of capacitor C and resistor RC across each thyristor. This resistance RC (along with parallel connected diode)

    • Options
    • A. limits charging current
    • B. limits discharging current
    • C. limits both charging and discharging currents
    • D. none of the above
      • Discuss

    Comments

    There are no comments.
Enter a new Comment




Aptitude

Engineering

Programming

Reasoning

Links

Copyright ©CuriousTab. All rights reserved.