Induction and Synchronous Machines MCQs (Part-3)

What is the function of the rotor in an induction motor?

A Induce current
B Rotate with magnetic field
C Supply power
D Generate magnetic field

What happens if the load increases in an induction motor?

A Torque decreases
B Speed increases
C Slip increases
D Slip decreases

Which motor type requires an external DC power supply for excitation?

A Synchronous motor
B Stepper motor
C Universal motor
D Induction motor

What causes rotor currents in an induction motor?

A Through rotor resistance
B External voltage
C Slip rings
D Stator magnetic field

What is the key feature of a wound rotor induction motor?

A Squirrel cage rotor
B Permanent magnet
C External resistances
D Slip rings

In which type of motor is the rotor always at synchronous speed?

A Synchronous motor
B Universal motor
C Induction motor
D Series motor

What does the slip in an induction motor indicate?

A Difference between rotor and synchronous speed
B Speed of the rotor
C Power consumption
D Current in the rotor

What does the voltage regulation of a synchronous generator indicate?

A Efficiency of the motor
B Torque capability
C Change in voltage with load
D Stability of frequency

What is the primary disadvantage of a single phase induction motor?

A High slip
B Low efficiency
C No starting torque
D High torque

What type of motor is most commonly used in industrial fans?

A Induction motor
B Universal motor
C Synchronous motor
D Stepper motor

What type of rotor is used in most small, low power induction motors?

A Wound rotor
B Slip ring rotor
C Squirrel cage rotor
D Permanent magnet rotor

What happens in a synchronous motor if excitation is too low?

A Motor operates at higher speed
B Efficiency increases
C Rotor slows down
D Motor loses synchronization

What is the main advantage of using a three phase system for induction motors?

A Rotor resistance
B Higher efficiency
C Low cost
D Easy maintenance

What is the typical starting method for large induction motors?

A Capacitor starting
B Direct on line starting
C Star delta starting
D Rotor resistance starting

What happens if an induction motor operates at synchronous speed?

A It loses torque production
B It produces maximum torque
C It operates with no slip
D It accelerates further