The torque produced by a single-phase induction motor fed by an ac voltage controller for speed control due to

A)
A fundamental component of current only
B)
A fundamental component of harmonics only
C)
Fundamental component and even harmonics
D)
A fundamental component of harmonics as well as current

Correct Answer : Option (A) :   A fundamental component of current only

Explanation : Single-phase induction motors work on single-phase AC supply. It has two windings; Main windings and auxiliary winding. For speed control of a single-phase induction motor by an ac voltage controller, and only a fundamental component of current is required to develop a toque. The harmonics in the motor current may cause power losses resulting in heating of the motor.

Recently Updated in Power Electronics Questions
Static UPS requires ______
A)
only rectifier
B)
only inverter
C)
both inverter and rectifier
D)
None of the above

Correct Answer :   both inverter and rectifier

Explanation : Rectifier to converter the dc from the battery to ac. Inverter to charge the battery from mains.

HVDC transmission has ___________ as compared to HVAC transmission.
A)
higher corona loss
B)
smaller transformer size
C)
smaller power transfer capabilities
D)
smaller conductor size

Correct Answer :   smaller conductor size

Explanation : The conductor size is smaller as there is no sink effect, and the whole conductor is utilized for transmitting power.

SPMS are based on the ________ principle.
A)
MOSFET
B)
Chopper
C)
Phase control
D)
Integral control

Correct Answer :   Chopper

Explanation : SMPS (Switching mode power supply) are based on the chopper principle. The output dc voltage is controlled by varying the duty cycle of the chopper circuit.

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