Explore topic-wise MCQs in Electrical Machines.

This section includes 20 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Machines knowledge and support exam preparation. Choose a topic below to get started.

1.

In the following circle diagram, what is CC’?

A. full load condition
B. no load condition
C. fixed losses
D. rated full load losses
Answer» B. no load condition
2.

Use the below circle diagram to choose the correct option.

A. CF: Rotor copper loss, FG: Stator copper loss, GE: Fixed losses.
B. FG:Rotor copper loss, CF: Stator copper loss, GE: Fixed losses.
C. GE:Rotor copper loss, FG: Stator copper loss, CF: Fixed losses.
D. FG:Rotor copper loss, CF: Stator copper loss, CF: Core losses.
Answer» B. FG:Rotor copper loss, CF: Stator copper loss, GE: Fixed losses.
3.

If the no load test is conducted at its rated frequency but less than the rated voltage, then the mechanical losses will _____ and the constant losses will _________

A. constant, reduce
B. constant, rise
C. reduce, rise
D. constant, constant
Answer» B. constant, rise
4.

If the no load test is conducted at its rated frequency but less than the rated voltage, then the wattmeter reading will be ____________

A. reduced
B. more than previous reading
C. remain same
D. none of the mentioned
Answer» B. more than previous reading
5.

Stator resistance can be measured using Kelvin’s double bridge.

A. True
B. False
Answer» B. False
6.

In the following circle diagram of the induction motor, QN is the ____________

A. rotor current referred to stator
B. stator current
C. stator current referred to rotor
D. no load input to rotor
Answer» B. stator current
7.

In the below circle diagram, OG represents?

A. Rated torque
B. Maximum torque
C. Rated power output
D. Losses
Answer» B. Maximum torque
8.

Blocked rotor test is conducted to find the ____________

A. leakage impedance
B. leakage reactance
C. stator impedance
D. rotor impedance
Answer» B. leakage reactance
9.

A 10kW, 50 Hz, 3-phase induction motor develops the rated torque at 1440rpm. If the load torque is reduced to half, then the power output that can now be obtained is?

A. 5 kW
B. 5.3 KW
C. 4.6 kW
D. 8 kW
Answer» B. 5.3 KW
10.

A 10kW, 50 Hz, 3-phase induction motor develops the rated torque at 1440rpm. If the load torque is reduced to half, then the motor speed is?

A. 1470rpm
B. 1410rpm
C. 1400rpm
D. 1444rpm
Answer» B. 1410rpm
11.

Circle diagram depicts the relation between ____________

A. stator current and the slip variation
B. rotor current and stator current
C. slip variation and the power factor
D. slip variation and the losses of the machine
Answer» B. rotor current and stator current
12.

Circle diagram of an induction motor is graphical representation of ____________

A. its equivalent circuit
B. its rotor equivalent
C. its stator equivalent
D. its stationary equivalent circuit
Answer» B. its rotor equivalent
13.

If the no load test is conducted at its rated frequency but less than the rated voltage, then the wattmeter reading will be$

A. reduced
B. more than previous reading
C. remain same
D. none of the mentioned
Answer» B. more than previous reading
14.

Stator_resistance_can_be_measured_using_Kelvin’s_double_bridge.$#

A. True
B. False
Answer» B. False
15.

If the no load test is conducted at its rated voltage but less than the rated frequency.

A.
B.
Answer» B.
16.

No load power factor of the induction motor will __________ if the no load test is conducted at its rated frequency but less than the rated voltage.

A. improve
B. degrade
C. remain same
D. none of the mentioned
Answer» B. degrade
17.

If_the_no_load_test_is_conducted_at_its_rated_frequency_but_less_than_the_rated_voltage,_then_the_mechanical_losses_will_______and_the_constant_losses_will__________

A. constant, reduce
B. constant, rise
C. reduce, rise
D. constant, constant
Answer» B. constant, rise
18.

Blocked rotor test is conducted to find the

A. leakage impedance
B. leakage reactance
C. stator impedance
D. rotor impedance
Answer» B. leakage reactance
19.

A 10kW, 50 Hz, 3-phase induction motor develops the rated torque at 1440rpm. If the load torque is reduced to half, then the power output that can now be obtained is

A. 5 kW
B. 5.3 KW
C. 4.6 kW
D. 8 kW
Answer» B. 5.3 KW
20.

A 10kW, 50 Hz, 3-phase induction motor develops the rated torque at 1440rpm. If the load torque is reduced to half, then the motor speed is

A. 1470rpm
B. 1410rpm
C. 1400rpm
D. 1444rpm
Answer» B. 1410rpm