Power Electronics

MCQsQuestion.com has 280 Question/Answers about Topic Power Electronics

Assertion (A): Thyristors can be used in controlled heating, excitation systems of alternators, speed control of motors and HVDCReason (R): A static var system using thyristors is very commonly used in high voltage ac systems.

Assertion (A):  Thyristors can be used in controlled heating, excitation systems of alternators, speed control of motors and HVDCReason (R):  A static var system using thyristors is very commonly used in high voltage ac systems.
  • 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
  • Correct Answer: Option B

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

Assertion (A):  A cycloconverter may be line commutated or forced commutatedReason (R):  A step up cycloconverter requires forced commutation.
  • 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
  • Correct Answer: Option A

Assertion (A): An ac regulator uses natural commutationReason (R): An ac regulator can be used for static on load tap changing of transformer.

Assertion (A):  An ac regulator uses natural commutationReason (R):  An ac regulator can be used for static on load tap changing of transformer.
  • 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
  • Correct Answer: Option B

Assertion (A): A class C chopper can operate in first and second quadrants Reason (R): A class B chopper operates only in second quadrant.

Assertion (A):  A class C chopper can operate in first and second quadrants Reason (R):  A class B chopper operates only in second quadrant.
  • 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
  • Correct Answer: Option B

Assertion (A): Chopper always requires forced commutationReason (R): Morgan chopper uses a saturable reactor.

Assertion (A):  Chopper always requires forced commutationReason (R):  Morgan chopper uses a saturable reactor.
  • 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
  • Correct Answer: Option B

Assertion (A): If the duty cycle of chopper is low the current would not become discontinuousReason (R): If the time constant L/R of the load in chopper is low the current may become discontinuous.

Assertion (A):  If the duty cycle of chopper is low the current would not become discontinuousReason (R):  If the time constant L/R of the load in chopper is low the current may become discontinuous.
  • 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
  • Correct Answer: Option C

Assertion (A): The output voltage of an inverter can be controlled by PWM techniqueReason (R): In a current source inverter the input current is constant.

Assertion (A):  The output voltage of an inverter can be controlled by PWM techniqueReason (R):  In a current source inverter the input current is constant.
  • 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
  • Correct Answer: Option B

Assertion (A): McMurray Bredford half bridge inverter uses complementary commutationReason (R): Three phase inverter can have two modes of operation.

Assertion (A):  McMurray Bredford half bridge inverter uses complementary commutationReason (R):  Three phase inverter can have two modes of operation.
  • 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
  • Correct Answer: Option B

Assertion (A): An inverter does not require forced commutation Reason (R): A series inverter is a forced commutation inverter.

Assertion (A):  An inverter does not require forced commutation Reason (R):  A series inverter is a forced commutation inverter.
  • 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
  • Correct Answer: Option D

Assertion (A): A dual converter may be circulating current type or non circulating current type.Reason (R): In circulating current dual converter only one converter can be operated at one time.

Assertion (A):  A dual converter may be circulating current type or non circulating current type.Reason (R):  In circulating current dual converter only one converter can be operated at one time.
  • 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
  • Correct Answer: Option C

Assertion (A): A fully controlled bridge converter can operate in first and fourth quadrant.Reason (R): A semi converter is cheaper than a full converter.

Assertion (A):  A fully controlled bridge converter can operate in first and fourth quadrant.Reason (R):  A semi converter is cheaper than a full converter.
  • 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
  • Correct Answer: Option B

Assertion (A): A half wave controlled rectifier has poorer efficiency and higher ripple factor than a full wave controlled rectifier.Reason (R): The use of a freewheeling diode in half wave controlled rectifier circuit improves the waveform of load current and circuit power factor.

Assertion (A):  A half wave controlled rectifier has poorer efficiency and higher ripple factor than a full wave controlled rectifier.Reason (R):  The use of a freewheeling diode in half wave controlled rectifier circuit improves the waveform of load current and circuit power factor.
  • 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
  • Correct Answer: Option B

Assertion (A): An ideal rectifier should have unity harmonic factorReason (R): An ideal rectifier should have unity displacement factor.

Assertion (A):  An ideal rectifier should have unity harmonic factorReason (R):  An ideal rectifier should have unity displacement factor.
  • 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
  • Correct Answer: Option D

Assertion (A): A transistor has lower voltage drop during conduction as compared to thyristorReason (R): Transistors are manufactured in very high voltage and current ratings.

Assertion (A):  A transistor has lower voltage drop during conduction as compared to thyristorReason (R):  Transistors are manufactured in very high voltage and current ratings.
  • 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
  • Correct Answer: Option C

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.

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.
  • 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
  • Correct Answer: Option C
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