Test: SCR Commutation Techniques

# Test: SCR Commutation Techniques

Test Description

## 20 Questions MCQ Test Power Electronics | Test: SCR Commutation Techniques

Test: SCR Commutation Techniques for Electrical Engineering (EE) 2023 is part of Power Electronics preparation. The Test: SCR Commutation Techniques questions and answers have been prepared according to the Electrical Engineering (EE) exam syllabus.The Test: SCR Commutation Techniques MCQs are made for Electrical Engineering (EE) 2023 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests for Test: SCR Commutation Techniques below.
Solutions of Test: SCR Commutation Techniques questions in English are available as part of our Power Electronics for Electrical Engineering (EE) & Test: SCR Commutation Techniques solutions in Hindi for Power Electronics course. Download more important topics, notes, lectures and mock test series for Electrical Engineering (EE) Exam by signing up for free. Attempt Test: SCR Commutation Techniques | 20 questions in 20 minutes | Mock test for Electrical Engineering (EE) preparation | Free important questions MCQ to study Power Electronics for Electrical Engineering (EE) Exam | Download free PDF with solutions
 1 Crore+ students have signed up on EduRev. Have you?
Test: SCR Commutation Techniques - Question 1

### The thyristor turn-off requires that the anode current

Detailed Solution for Test: SCR Commutation Techniques - Question 1

For effective turn-off of the SCR the anode current must fall below the holding current value.

Test: SCR Commutation Techniques - Question 2

### In case of class A type commutation or load commutation with low value of R load the

Detailed Solution for Test: SCR Commutation Techniques - Question 2

In case of Class A commutation the requirement is that the circuit should be an under-damped RLC circuit.

Test: SCR Commutation Techniques - Question 3

### The class A commutation or load commutation is possible in case of

Detailed Solution for Test: SCR Commutation Techniques - Question 3

The nature of the circuit should be such that when energized from the source, current must a a natural tendency to decay to zero for load commutation to occur in a SCR circuit.

Test: SCR Commutation Techniques - Question 4

In case of class B commutation or resonant-pulse commutation with L = 5 μH and C = 20 μC with initial voltage across the capacitor (Vs) = 230 V. Find the peak value of resonant current.

Detailed Solution for Test: SCR Commutation Techniques - Question 4

Ip = Vs x √C/L.

Test: SCR Commutation Techniques - Question 5

In case of class B commutation or resonant-pulse commutation with L = 5 μH and C = 20 μC with the initial voltage across the capacitor (Vs) = 230 V. Find the conduction time for auxiliary thyristor.

Detailed Solution for Test: SCR Commutation Techniques - Question 5

Ip = Vs x √C/L
ω = 1/√LC
t = π/ω.

Test: SCR Commutation Techniques - Question 6

An SCR is connected in series with L = 5 mH and C = 20 μF. Find the resonant frequency of the circuit.

Detailed Solution for Test: SCR Commutation Techniques - Question 6

ω = 1/√LC.

Test: SCR Commutation Techniques - Question 7

The type of commutation when the load is commutated by transferring its load current to another incoming thyristor is

Detailed Solution for Test: SCR Commutation Techniques - Question 7

In the Class C type commutation also called as complementary commutation the load is commutated by transferring the current th another device.

Test: SCR Commutation Techniques - Question 8

The type of commutation in which the pulse to turn off the SCR is obtained by separate voltage source is

Detailed Solution for Test: SCR Commutation Techniques - Question 8

In class E commutation, another voltage source is used. It is also called as external pulse commutation.

Test: SCR Commutation Techniques - Question 9

The natural reversal of ac supply voltage commutates the SCR in case of

Detailed Solution for Test: SCR Commutation Techniques - Question 9

Both line and natural commuataion are used in converters.

Test: SCR Commutation Techniques - Question 10

___________ commutation technique is commonly employed in series inverters.

Detailed Solution for Test: SCR Commutation Techniques - Question 10

Load commuation is used in inverter in which L and C are connected in series with the load or C in parallel with the load such that overall load circuit is under damped.

Test: SCR Commutation Techniques - Question 11

For the circuit shown in the figure below,

C = 4 pF
L = 16 μH
Vs = 200V
The capacitor voltage after the SCR is self commutated is

Detailed Solution for Test: SCR Commutation Techniques - Question 11

It is simply the negative of Vs as it is a series circuit & after turn off the whole voltage appears across the thyristor.

Test: SCR Commutation Techniques - Question 12

For the circuit shown below,

The maximum value of current through thyristors T1 & TA can be given by

Detailed Solution for Test: SCR Commutation Techniques - Question 12

I1 = (Vs/R)
T2 = (Vs√C/L).

Test: SCR Commutation Techniques - Question 13

For the circuit shown in the figure below,

C = 4 pF
L = 16 μH
Vs = 200 V
The peak thyristor current is

Detailed Solution for Test: SCR Commutation Techniques - Question 13

The peak SCR current is Vs/2.

Test: SCR Commutation Techniques - Question 14

For the circuit shown in the figure below, ___ type of commutation would take place for the SCR (THY1)

Detailed Solution for Test: SCR Commutation Techniques - Question 14

The given figure is that of a class B commutation or resonant-pulse commutation, which is a type of forced commutation technique.

Test: SCR Commutation Techniques - Question 15

For the circuit shown in the figure below

R1 = 50 Ω, R2 = 100 Ω, Vs = 100 V. At the time of turn-on of the SCR, initial thyristor current is

Detailed Solution for Test: SCR Commutation Techniques - Question 15

Io = Vs x [(2/R1)+(1/R2)].

Test: SCR Commutation Techniques - Question 16

Natural commutation of an SCR takes place when

Detailed Solution for Test: SCR Commutation Techniques - Question 16

Anode current (load current) becomes zero and turns off the device, hence the name line commutation.

Test: SCR Commutation Techniques - Question 17

___________ commutation is usually used in phase-controlled rectifiers

Detailed Solution for Test: SCR Commutation Techniques - Question 17

Line commuataion is used in converters.

Test: SCR Commutation Techniques - Question 18

Parallel-capacitor commutation is

Detailed Solution for Test: SCR Commutation Techniques - Question 18

Parallel capacitor is another name for forced commutation.

Test: SCR Commutation Techniques - Question 19

Class E commutation is a/an

Detailed Solution for Test: SCR Commutation Techniques - Question 19

As an external source is used it is a external-pulse commutation technique.

Test: SCR Commutation Techniques - Question 20

Below is the circuit of a resonant-pulse commutation, the maximum voltage to which the capacitor C charges is

Detailed Solution for Test: SCR Commutation Techniques - Question 20

The capacitor charges from 0 to Vs with the right side plate positive.

## Power Electronics

5 videos|39 docs|63 tests
 Use Code STAYHOME200 and get INR 200 additional OFF Use Coupon Code
Information about Test: SCR Commutation Techniques Page
In this test you can find the Exam questions for Test: SCR Commutation Techniques solved & explained in the simplest way possible. Besides giving Questions and answers for Test: SCR Commutation Techniques, EduRev gives you an ample number of Online tests for practice

## Power Electronics

5 videos|39 docs|63 tests