A cycloconverter cannot give a frequency higher than input frequency. True False

CuriousTab

CuriousTab

Home Aptitude

Discussion

Home ‣ Electronics and Communication Engineering ‣ Power Electronics Comments

Question
A cycloconverter cannot give a frequency higher than input frequency.
Options
A. True
B. False

Correct Answer

False

Explanation

Step up cycloconverter can give a frequency higher than input frequency.

Power Electronics problems

Search Results

1. A single phase full wave regulator feeds R-L load. The best gating signal is
Options
A. short duration pulses
B. long duration pulses
C. pulse train
D. either (a) or (b)

2. Assertion (A): When an SCR is conducting, the voltage drop across is about 1 V.
Reason (R): When an SCR is conducting, the junction temperature is about 200�C.
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

3. When the core of a saturable reactor is saturated, the inductance is high.
Options
A. True
B. False

5. A 3 phase semiconverter when supplying a certain load has a rectification efficiency of 0.6 and transformer utilisation factor of 0.35. When a 3 phase full converter is supplying the same load
Options
A. rectification efficiency will be more than 0.6 and TUF will be more than 0.35
B. rectification efficiency will be more than 0.6 but TUF will be less than 0.35
C. rectification efficiency will be less than 0.6 and TUF will be less than 0.35
D. rectification efficiency will be less than 0.6 but TUF will be more than 0.35

6. A 3 phase induction motor is fed by a 3 phase ac regulator to change the stator voltage. The variation in speed will be more if
Options
A. load torque is constant
B. load torque increases with increase in speed
C. load torque decreases with increase in speed
D. either (a) or (b)

7. Assertion (A): A cycloconverter may be line commutated or forced commutated
Reason (R): A step up cycloconverter requires forced commutation.
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

9. A single phase electric heater uses phase controlled thyristors. The firing angle is 90�. The degree of heating is
Options
A. 25% of maximum
B. 50% of maximum
C. 75% of maximum
D. none of the above

10. In a single phase full bridge converter (B - 2 connection), the input voltage is v = V_m sin ?t. The output dc voltage for resistive load
Options
A.
B.
C.
D.

Comments

There are no comments.

More in Electronics and Communication Engineering: