AC/DC Conversion MCQ Questions & Answers

Question 1

____________ is the boundary for C.C.M and D.C.M mode in 3-? Full wave bridge rectifier for R load.

A. 60°
B. 10°
C. 80°
D. 50°

Question 2

Calculate the average value of thyristor current in 3-? Full wave converter for the load current=9 A and ?=26°.

A. 4 A
B. 5 A
C. 7 A
D. 3 A

Question 3

Calculate the compensator rating required for sin(?)=.13.

A. 0.45 P.U
B. 0.12 P.U
C. 0.13 P.U
D. 0.82 P.U

Question 4

Calculate the De-rating factor if the string efficiency is 16 %.

A. 0.84
B. 0.44
C. 0.5
D. 0.6

Question 5

Calculate the r.m.s value of thyristor current in 3-? Full wave converter for the load current=4 A and ?=12°.

A. 2.3 A
B. 2.5 A
C. 2.7 A
D. 2.9 A

Question 6

Fifth lowest order harmonic present in 3-? fully controlled rectifier is __________

A. 15th
B. 17th
C. 13th
D. 12th

Question 7

For ? > 90°, 3-? Full wave bridge rectifier acts as a natural commutated inverter.

A. True
B. False

Question 8

Full form of DIAC is ___________

A. Digital Alternating current
B. Discrete Alternating current
C. Diode for Alternating current
D. Digital Alternating counter

Question 9

Full form of FET is ___________

A. Field effect transistor
B. Field engage transistor
C. Field effect terminal
D. Fire engage transistor

Question 10

Full form of MOSFET is ___________

A. Metal oxide silicon field effect transistor
B. Metal oxide semiconductor field effect transistor
C. Metal oxide settle field effect transistor
D. Metal oriented silicon field effect transistor

Question 11

The output voltage of 3-? Full wave bridge rectifier is six times of 3-? Half-wave rectifier.

A. True
B. False

Question 12

What is the formula for output voltage for 3-? Full wave bridge rectifier for R load for ? < 60°?

A. 2Vml(cos(?))÷?
B. 3Vml(cos(?))÷2?
C. 3Vml(cos(?))÷?
D. 6Vml(cos(?))÷?

Question 13

What is the formula for output voltage for 3-? Full wave bridge rectifier for R load for ? > 60°?

A. 2Vml(1+cos(?+60°))÷?
B. 3Vml(1+cos(60°+?))÷2?
C. 3Vml(1+cos(60°+?))÷?
D. 6Vml(cos(?))÷?

Question 14

What is the formula for output voltage for 3-? Full wave bridge rectifier for R-L load?

A. 3Vml(cos(?))÷2?
B. 3Vml(cos(?))÷?
C. 2Vml(cos(?))÷?
D. 6Vml(cos(?))÷?

Question 15

Which harmonic is not present in 3-? fully controlled rectifier?

A. 81st harmonic
B. 15th harmonic
C. 17th harmonic
D. 11th harmonic

Question 16

____________ is the boundary for C.C.M and D.C.M mode in 3-Φ Full wave bridge rectifier for R load.

A. 60°
B. 10°
C. 80°
D. 50°

Question 17

Calculate the average value of thyristor current in 3-Φ Full wave converter for the load current=9 A and α=26°.

A. 4:00 AM
B. 5:00 AM
C. 7:00 AM
D. 3:00 AM

Question 18

Calculate the compensator rating required for sin(Φ)=.13.

A. 0.45 P.U
B. 0.12 P.U
C. 0.13 P.U
D. 0.82 P.U

Question 19

Calculate the r.m.s value of thyristor current in 3-Φ Full wave converter for the load current=4 A and α=12°.

A. 2.3 A
B. 2.5 A
C. 2.7 A
D. 2.9 A

Question 20

Fifth lowest order harmonic present in 3-Φ fully controlled rectifier is __________

A. 15th
B. 17th
C. 13th
D. 12th

Question 21

For α > 90°, 3-Φ Full wave bridge rectifier acts as a natural commutated inverter.

A. TRUE
B. FALSE

Question 22

The output voltage of 3-Φ Full wave bridge rectifier is six times of 3-Φ Half-wave rectifier.

A. TRUE
B. FALSE

Question 23

What is the formula for output voltage for 3-Φ Full wave bridge rectifier for R load for α < 60°?

A. 2Vml(cos(∝))÷π
B. 3Vml(cos(∝))÷2π
C. 3Vml(cos(∝))÷π
D. 6Vml(cos(∝))÷π

Question 24

What is the formula for output voltage for 3-Φ Full wave bridge rectifier for R load for α > 60°?

A. 2Vml(1+cos(∝+60°))÷π
B. 3Vml(1+cos(60°+∝))÷2π
C. 3Vml(1+cos(60°+∝))÷π
D. 6Vml(cos(∝))÷π

Question 25

What is the formula for output voltage for 3-Φ Full wave bridge rectifier for R-L load?

A. 3Vml(cos(∝))÷2π
B. 3Vml(cos(∝))÷π
C. 2Vml(cos(∝))÷π
D. 6Vml(cos(∝))÷π

Question 26

Which harmonic is not present in 3-Φ fully controlled rectifier?

A. 81st harmonic
B. 15th harmonic
C. 17th harmonic
D. 11th harmonic