Electrical Machines (Part-9)

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

A To improve efficiency
B To increase speed
C To reduce mechanical wear
D To stop the motor quickly

Which braking method involves using the motor’s own energy to slow it down?

A Plugging
B Regenerative braking
C Mechanical braking
D Dynamic braking

What happens to the torque in a motor when the load increases?

A Torque remains constant
B Torque decreases
C Torque increases
D Torque fluctuates

What is the purpose of an equivalent circuit in electrical machines?

A To model the machine’s behavior
B To predict efficiency
C To reduce losses
D To increase torque

Which of the following is a characteristic of the load characteristics of a motor?

A Variable speed
B Constant current
C Constant speed
D Constant torque

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

A Frequency deviation
B Speed difference
C Current change
D Voltage variation

What is the effect of increasing the load on the efficiency of a motor?

A Efficiency remains constant
B Efficiency increases
C Efficiency fluctuates
D Efficiency decreases

Which braking method involves reversing the motor’s direction to stop it?

A Plugging
B Dynamic braking
C Regenerative braking
D Mechanical braking

What is the effect of load characteristics on the performance of an electrical motor?

A Determines the speed
B Affects voltage regulation
C Affects torque and speed
D Affects the efficiency

Which of the following methods is used to reduce the starting current of an induction motor?

A Direct‐on‐line starting
B Autotransformer starting
C Slip‐ring starting
D Star‐delta starting

What is the purpose of a dynamic braking system in electrical machines?

A To improve torque
B To stop the motor quickly
C To increase speed
D To reduce energy consumption

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

A Hysteresis losses
B Eddy currents
C Mechanical losses
D Copper losses

In an electrical machine, what happens to the current drawn from the supply during startup?

A It increases
B It fluctuates
C It decreases
D It remains constant

What is the primary function of the equivalent circuit in a motor?

A To calculate efficiency
B To predict motor behavior
C To represent energy losses
D To simulate load

Which braking method is most commonly used for high‐speed motors?

A Dynamic braking
B Plugging
C Regenerative braking
D Mechanical braking