Electrical Machines (Part-16)

What is the primary purpose of braking methods in electrical machines?

A Increase speed
B Stop quickly
C Increase torque
D Improve efficiency

What is the function of the armature in a DC motor?

A Generate magnetic field
B Convert electrical energy to mechanical
C Control speed
D Reverse current

What is the purpose of the field winding in a DC motor?

A Generate mechanical power
B Create magnetic field
C Reverse current direction
D Control motor speed

How does the slip in an induction motor affect torque?

A Increases torque
B Decreases torque
C No effect
D Fluctuates

What does the equivalent circuit of an electrical machine represent?

A Mechanical components
B Magnetic losses
C Electrical and mechanical behavior
D Speed characteristics

What is the effect of load variation on the voltage regulation of a generator?

A Decreases voltage
B Increases voltage
C No effect
D Fluctuates

What is the primary cause of core losses in an electrical machine?

A Mechanical losses
B Eddy currents and hysteresis
C Resistance in windings
D Overloading

What is the role of the excitation system in a synchronous generator?

A To maintain constant speed
B To regulate the output voltage
C To generate mechanical power
D To reverse current direction

What is the effect of increasing the number of poles in a synchronous motor?

A Decreases torque
B Increases speed
C Decreases speed
D Increases efficiency

How does temperature affect the performance of an electrical machine?

A Improves efficiency
B Decreases efficiency
C Increases torque
D Increases speed

What is the main characteristic of stepper motors?

A Continuous rotation
B Precise position control
C High torque at high speeds
D Low efficiency

What is the impact of high harmonics on the performance of electrical machines?

A Increases efficiency
B Reduces torque
C Increases losses
D No effect

What is the effect of a high load on an induction motor’s efficiency?

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

What is the primary function of insulation in an electrical machine?

A Increase speed
B Prevent electrical faults
C Improve torque
D Control temperature

What is the key characteristic of a brushless DC motor?

A Requires external field current
B Uses a controller for commutation
C Uses brushes for commutation
D Operates at constant speed