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  • Question
  • Modified Mc Murray full bridge inverter uses


  • Options
  • A. 4 thyristors and 2 diodes
  • B. 4 thyristors and 4 diodes
  • C. 8 thyristors and 4 diodes
  • D. 8 thyristors and 8 diodes

  • Correct Answer
  • 8 thyristors and 8 diodes 


  • Power Electronics problems


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    • 1. The power factor at the input terminals of a cyclo- converter is generally

    • Options
    • A. low and leading
    • B. low and lagging
    • C. high and leading
    • D. high and lagging
    • Discuss
    • 2. A dc series motor is coupled to a load whose torque is proportional to speed. It is fed by a single phase ac supply through a full converter. When speed is 500 rpm, firing angle is 45°. It is desired to raise the speed. It will be necessary to

    • Options
    • A. decrease the firing angle
    • B. increase the firing angle
    • C. either decrease or increase the firing angle depending on the required speed
    • D. decrease the load torque
    • Discuss
    • 3. Assertion (A): Thyristors can be used in controlled heating, excitation systems of alternators, speed control of motors and HVDC

      Reason (R): A static var system using thyristors is very commonly used in high voltage ac systems.


    • Options
    • A. Both A and R are correct and R is correct explanation of A
    • B. Both A and R correct but R is not correct explanation of A
    • C. A is correct but R is wrong
    • D. A is wrong but R is correct
    • Discuss
    • 4. A LASCR has

    • Options
    • A. 4 semiconductor layers and 3 junctions
    • B. 3 semiconductor layers and 2 junctions
    • C. 2 semiconductor layers and 2 junctions
    • D. any of these depending on the rating
    • Discuss
    • 5. The number of layers in a Shockley diode are

    • Options
    • A. 2
    • B. 3
    • C. 4
    • D. 2 or 3
    • Discuss
    • 6. A fully controlled bridge converter feeds a highly inductive load such that the load current can be assumed to be constant. The wave shape of input current is

    • Options
    • A. dc
    • B. sinusoidal
    • C. rectangular
    • D. none of the above
    • Discuss
    • 7. The application of gate signal decreases the break over voltage of on SCR.

    • Options
    • A. True
    • B. False
    • Discuss
    • 8. Ripple factor RF and form factor FF are related as

    • Options
    • A. RF = FF2 - 1
    • B. RF = (FF2 - 1)0.5
    • C. RF = FF - 1
    • D. RF = (FF - 1)0.5
    • Discuss
    • 9. In integral cycle control of ac regulator, the input power factor is equal to

    • Options
    • A. duty cycle a
    • B. a2
    • C. a
    • D. (a)1/3
    • Discuss
    • 10. A single phase fully controlled bridge converter is feeding an RLE load. Input voltage is Vm sin ?t and firing angle is a. If average current is I0, then

    • Options
    • A. cos a = RI0 + E
    • B. cos a = RE0 + E
    • C. cos a = E0 - RI0
    • D. cos a = E - RI0
    • Discuss


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