Induction and Synchronous Machines MCQs (Part-6)

What determines the synchronous speed of a motor?

A Load applied
B Stator resistance
C Frequency and poles
D Rotor resistance

What does slip in an induction motor indicate?

A Magnetic field strength
B Speed difference
C Load applied
D Rotor resistance

What happens to the torque of an induction motor as the load increases?

A Torque increases
B Torque becomes unstable
C Torque remains constant
D Torque decreases

What is the primary function of a synchronous motor?

A High starting torque
B High torque production
C Variable speed operation
D Constant speed operation

What is the effect of an increase in load on the slip of an induction motor?

A Slip remains constant
B Slip decreases
C Slip increases
D Slip becomes negative

Which part of the synchronous motor must be supplied with DC current?

A Shaft
B Rotor windings
C Bearings
D Stator windings

What is the primary cause of core losses in an induction motor?

A Eddy currents
B Stator windings
C Rotor resistance
D Slip rings

How does the torque speed characteristic of an induction motor look?

A Horizontal
B Linear
C S shaped
D Parabolic

In a synchronous motor, what happens when the excitation is too low?

A Motor operates at higher speed
B Motor accelerates
C Motor increases torque
D Motor loses synchronization

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

A To provide external resistances
B To regulate voltage
C To generate power
D To control speed

What happens to the rotor current when the slip of an induction motor increases?

A Remains constant
B Increases
C Becomes zero
D Decreases

What is the characteristic of a squirrel cage rotor in an induction motor?

A Uses external resistances
B Requires slip rings
C Simple and maintenance free
D Provides high starting torque

What happens to an induction motor if the load is removed?

A Rotor speed increases
B Efficiency decreases
C Slip increases
D Rotor speed decreases

How does an increase in voltage affect the speed of an induction motor?

A Reduces efficiency
B Increases speed
C Decreases speed
D No effect on speed

What is the role of the exciter in a synchronous motor?

A Control power factor
B Regulate rotor speed
C Provide DC current to the rotor
D Start the motor