Ojective Question

power-electronics-mcqs - Set (3)

Correct Answer: Orange && Worng Answer: Red

1. Electric Derive is becoming more and more popular because

(A). It is simple and reliable

(B). It is cheaper in cost

(C). It provides smooth and easy control

(D). All of the above

View Answer

Explanation: Not Avilable

2. Which converter (s) can be used for D.C. series motor control-

(A). Semi-converters

(B). Half-wave converters

(C). Full-converters

(D). Semi-converters and Full-converters

View Answer

Explanation: Not Avilable

3. Application of cyclo converters include

(A). Speed control of A.C. Drives

(B). Static VAR compensation

(C). Induction heating

(D). All of the above

View Answer

Explanation: Not Avilable

4. In Induction heating, which of the following is abnormally high?

(A). Phase Angle

(B). Frequency

(C). Current

(D). Voltage

View Answer

Explanation: Not Avilable

5. Over Charging of the battery results in –

(A). High temp, Corrosion of plates, Oxidation of scparators, loss of water

(B). Irreversible sulphation, reversal of cells loss of capacity

(C). Battery is in good condition

(D). All of the above

View Answer

Explanation: Not Avilable

6. A Thyristor is a

(A). P-N-P device

(B). N-P-N device

(C). P-N-P-N device

(D). P-N device

View Answer

Explanation: Not Avilable

7. The static V-I curve for the Thyristor is plotted for

(A). Anode current vs gate current for different values of Anode-cathode voltage

(B). Anode current vs Anode-cathode voltage for different values of gate current

(C). Anode cathode voltage vs gate current for different values of Anode current

(D). Gate current vs Gate voltage for different values of Anode current

View Answer

Explanation: Not Avilable

8. For the Thyristor to remain in the conducting(ON) state

(A). Gate signal is continuously required

(B). No continuous gate signal is required

(C). No forward Anode-cathode voltage is required

(D). Negative gate signal is continuously required

View Answer

Explanation: Not Avilable

9. The forward dv/dt rating of an SCR

(A). Increase with increase in Junction temp.

(B). Decrease with increase in Junction temp.

(C). Increase with decrease in RMS value of forward Anode-cathode voltage

(D). Decrease with decrease in RMS value of forward Anode-cathode voltage

View Answer

Explanation: Not Avilable

10. In a single phase Half-wave circuit with load RL and a free-wheeling Diode, the load voltage during free-wheeling period will be

(A). Zero

(B). Positive

(C). Negative

(D). Positive then Negative

View Answer

Explanation: Not Avilable

11. A single phase full controlled bridge converter uses

(A). 4 SCRs and 2 Diodes

(B). 4 SCRs

(C). 6 SCRs

(D). 2 SCRs and 4 Diodes

View Answer

Explanation: Not Avilable

12. A three-phase three-pulse, M-3 type controlled converter uses number of SCRs

(A). One

(B). Two

(C). Three

(D). Frour

View Answer

Explanation: Not Avilable

13. A cycloconverter is a :

(A). Frequency changer from higher to lower frequency with one-stage conversion

(B). Frequency changer from lower to higher with one-stage converison

(C). Both (a) and (b)

(D). Neither (a) Nor (b)

View Answer

Explanation: Not Avilable

14. A chopper may be thought as a :

(A). inverter with DC input

(B). DC equivalent of an AC Transformer

(C). Diode Rectifier

(D). DC equivalent of an Inducton Motor

View Answer

Explanation: Not Avilable

15. In Type C chopper, if only one switch is operated –

(A). Only one quadrant operation will be obtained

(B). Two quadrant operation will be obtained

(C). The chopper will not work

(D). None of the above

View Answer

Explanation: Only one quadrant operation will be operated if only one switch is used. It can be eihter 1st and 2nd quadrant depending on switch is operated.

16. In constant frequency system of chopper ________ is varied

(A). Vs

(B). Ton

(C). T

(D). f

View Answer

Explanation: Not Avilable

17. In voltage fed Thyristor inverters ________ commutation is required.

(A). Load

(B). Forced

(C). Self

(D). Any of the above

View Answer

Explanation: Not Avilable

18. In the single-pulse width modulation method the output voltage wave form is symmetrical about-

(A). π

(B). 2π

(C). π/2

(D). π/4

View Answer

Explanation: Not Avilable

19. Line-commutated inverters have

(A). A.C. on the supply side and DC on the load side

(B). A.C. on both supply and load side

(C). D.C. on both supply and load side

(D). D.C. on the supply side and A.C. on the load side

View Answer

Explanation: Not Avilable

20. The series-inverter control method is an

(A). Internal voltage control method

(B). External voltage control method

(C). External frequency control method

(D). None of the above

View Answer

Explanation: Not Avilable

1. Electric Derive is becoming more and more popular because

2. Which converter (s) can be used for D.C. series motor control-

3. Application of cyclo converters include

4. In Induction heating, which of the following is abnormally high?

5. Over Charging of the battery results in –

6. A Thyristor is a

7. The static V-I curve for the Thyristor is plotted for

8. For the Thyristor to remain in the conducting(ON) state

9. The forward dv/dt rating of an SCR

10. In a single phase Half-wave circuit with load RL and a free-wheeling Diode, the load voltage during free-wheeling period will be

11. A single phase full controlled bridge converter uses

12. A three-phase three-pulse, M-3 type controlled converter uses number of SCRs

13. A cycloconverter is a :

14. A chopper may be thought as a :

15. In Type C chopper, if only one switch is operated –

16. In constant frequency system of chopper ________ is varied

17. In voltage fed Thyristor inverters ________ commutation is required.

18. In the single-pulse width modulation method the output voltage wave form is symmetrical about-

19. Line-commutated inverters have

20. The series-inverter control method is an

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