Explore topic-wise MCQs in Dc Machines.

This section includes 6 Mcqs, each offering curated multiple-choice questions to sharpen your Dc Machines knowledge and support exam preparation. Choose a topic below to get started.

1.

For an ideal DC machine, which phenomenon will reduce the terminal voltage?

A. Armature reaction
B. Commutation
C. Armature ohmic losses
D. All will contribute in reducing the terminal voltage
Answer» C. Armature ohmic losses
Discussion
2.

For a constant emf, if field current is reduced then the speed of the DC motor will_____

A. Remains same
B. Increases
C. Decreases
D. Can t say
Answer» C. Decreases
Discussion
3.

A 4-pole wave wound DC motor drawing an armature current of 20 A has provided with 360 armature conductors. If the flux per pole is 0.015 Wb then the torque developed by the armature of motor is _______

A. 10.23 N-m
B. 34.37 N-m
C. 17.17 N-m
D. 19.08 N-m
Answer» C. 17.17 N-m
Discussion
4.

If the average coil emf of a DC motor is doubled and flux is halved (keeping other parameters constant) then its shaft speed will become ___________

A. Twice of the original speed
B. Square of the original speed
C. Four times of the original speed
D. Half of the original speed
Answer» D. Half of the original speed
Discussion
5.

If the no load speed of DC motor is 1300 rpm and full load speed is 1100 rpm, then its voltage regulation is ____________

A. 12.56%
B. 18.18 %
C. 17.39%
D. 18.39%
Answer» C. 17.39%
Discussion
6.

A 4-pole Dc wound machine is lap wound with 400 conductors. The pole shore is 20 cm long and average flux density over one-pole pitch is 0.4 T, the armature diameter being 30 cm. What is the value of flux/pole?

A. 0.188 Wb
B. 18.88 Wb
C. 0.0188 Wb
D. 1.888 Wb
Answer» D. 1.888 Wb
Discussion