Induction and Synchronous Machines MCQs (Part-5)

What is the main function of stator windings in an induction motor?

A Generate torque
B Supply excitation current
C Create rotating magnetic field
D Provide mechanical power

In which motor is a wound rotor typically used?

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

What happens to the slip of an induction motor at no load?

A It is high
B It is zero
C It is negative
D It is maximum

What is the effect of a high slip in an induction motor?

A Reduced efficiency
B Increased speed
C Increased torque
D Stable operation

What does a synchronous motor require for operation?

A DC excitation
B External resistances
C Rotor speed control
D High slip

What is the role of rotor windings in a wound rotor induction motor?

A Control rotor speed
B Maintain voltage stability
C Offer high starting torque
D Provide external power

Which of the following factors determines the synchronous speed of an induction motor?

A Stator resistance
B Frequency and poles
C Rotor resistance
D Slip

What is the primary difference between induction motors and synchronous motors?

A Induction motors run at synchronous speed
B Synchronous motors require slip rings
C Induction motors have no stator windings
D Synchronous motors require external excitation

What is the effect of high voltage on the stator windings of a synchronous motor?

A Reduced current
B Increased torque
C Overheating
D Higher speed

What does the term “slip” refer to in an induction motor?

A Speed variation
B Rotor current
C Voltage drop
D Magnetic field intensity

Which of the following is a disadvantage of squirrel cage rotors in induction motors?

A Requires slip rings
B Difficult to control speed
C High starting torque
D Low maintenance

What is the impact of increased load on an induction motor’s power factor?

A Power factor remains constant
B Power factor becomes unity
C Power factor increases
D Power factor decreases

What is the main purpose of slip rings in a wound rotor motor?

A Provide high torque
B Control rotor speed
C Transfer electrical energy
D Generate power

What causes core losses in an induction motor?

A Eddy currents and hysteresis
B Stator winding losses
C Rotor friction
D Magnetic leakage

What is the main advantage of using a wound rotor in induction motors?

A Simple design
B Low slip
C High starting torque
D Low cost