Electrical Machines (Part-2)

What is the main purpose of an armature in a DC motor?

A Control speed
B Generate a magnetic field
C Generate torque
D Convert mechanical energy

In which motor type is the field winding placed on the rotor?

A Synchronous motor
B DC motor
C Brushless motor
D Induction motor

What is the primary cause of mechanical losses in electrical machines?

A Resistance
B Friction
C Hysteresis
D Eddy currents

What is the role of cooling systems in electrical machines?

A Enhance torque
B Increase voltage
C Reduce vibration
D Prevent overheating

What type of motor is used in variable speed drives?

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

What does the efficiency of an electrical machine depend on?

A Current only
B Power losses
C Voltage only
D Frequency

What type of losses occur due to resistance in the windings of electrical machines?

A Mechanical losses
B Eddy current losses
C Core losses
D Copper losses

In which motor type does the rotor not require any external excitation?

A Induction motor
B Synchronous motor
C Permanent magnet motor
D DC motor

Which component is responsible for reversing the direction of current in the armature of a DC motor?

A Commutator
B Brushes
C Stator
D Rotor

What does voltage regulation measure in an electrical machine?

A Level of core losses
B Ability to maintain constant voltage
C Ability to maintain speed
D Resistance of windings

In an induction motor, what is the role of the stator?

A Control speed
B Reverse current direction
C Generate the magnetic field
D Provide mechanical energy

What is the primary function of an excitation system in synchronous motors?

A Provide field current
B Supply power
C Control speed
D Generate torque

Which of the following is the primary function of insulation in electrical machines?

A Increase torque
B Maintain speed
C Prevent electrical faults
D Reduce noise

What does the term “harmonics” refer to in electrical machines?

A Core temperature
B Low resistance losses
C High-speed operation
D Unwanted frequency components

What is the primary purpose of using a laminated core in electrical machines?

A Reduce eddy current losses
B Provide insulation
C Enhance mechanical strength
D Increase speed