Current derating may be necessary when thyristors are operating in series parall

CuriousTab

CuriousTab

Home Aptitude

Discussion

Home ‣ Electronics and Communication Engineering ‣ Power Electronics Comments

Question
Current derating may be necessary when thyristors are operating in
Options
A. series
B. parallel
C. series or parallel
D. none of the above

Correct Answer

parallel

Explanation

Since current does not divide equally, current derating is necessary.

Power Electronics problems

Search Results

2. If V_dc1 is the dc output voltage in half wave controlled rectifier circuit feeding resistive load and V_dc2 is the dc output voltage in full wave controlled rectifier circuit (M - 2 connection) feeding resistive load, then
Options
A. V_dc1 = 0.5 V_dc2 for all values of firing angle
B. V_dc1 = V_dc2 for all values of firing angle
C. V_dc1 ? 0.5 V_dc2 for all values of firing angle
D. V_dc1 ? 0.5 V_dc2 for all values of firing angle

3. In a circuit using a full wave converter (M - 2 connection) the PIV of each thyristor is 400 V. For the same output voltage and fully controlled bridge converter, PIV will be
Options
A. 400 V
B. 800 V
C. 200 V
D. 2002 V

4. In the below figure the average load current is 15 A. The rms value of transformer secondary current is
Options
A. 15 A
B. 10.61 A
C. 7.5 A
D. 14.14 A

5. Assertion (A): A TRIAC is a bidirectional SCR.
Reason (R): A TRIAC is a four layers 3 terminal device and can conduct in both directions.
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

6. Assertion (A): A transistor requires a continuous base signal for conduction but a thyristor requires a gate pulse.
Reason (R): Transistor find widespread application in power electronic circuits.
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

7. The phenomenon of overlap in converter operation due to
Options
A. source resistance
B. source inductance
C. both source resistance and source inductance
D. high value of firing angle

8. A single phase semiconverter is feeding a highly inductive load and has freewheeling diode across the load. The waveshapes of output voltage and output current
Options
A. are similar
B. are not similar
C. may be similar or dissimilar
D. are similar only if firing angle is zero

9. A semiconverter feeding an RLE load operates in
Options
A. first quadrant only
B. first and second quadrants
C. first and fourth quadrants
D. first and third quadrants

10. Assertion (A): Inverters and choppers use fast switching thyristors
Reason (R): Fast switching SCR has low turn off time.
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

Comments

There are no comments.

More in Electronics and Communication Engineering: