DC Motors MCQ

Test your knowledge with important DC Motors MCQ and their applications. These MCQs are beneficial for competitive exams too. Explore 30 + more DC Motors MCQs at Bissoy

• Calculate the active power in an 8 Ω resistor with 8 A current flowing through it.
  ক

  512 W

  খ

  514 W

  গ

  512 W

  ঘ

  518 W
• For a practical synchronous motor, the pull-out torque will occur when the torque angle is nearly equal to ________
  ক

  0°

  খ

  30°

  গ

  45°

  ঘ

  75°
• A 3-phase induction motor runs at almost 1500 rpm at no load and 900 rpm at full load when supplied with power from a 50 Hz, 3-phase supply. What is the corresponding speed of the rotor field with respect to the rotor?
  ক

  300 revolution per minute

  খ

  400 revolution per minute

  গ

  600 revolution per minute

  ঘ

  500 revolution per minute
• In an induction motor, when the number of stator slots is not equal to an integral number of rotor slots _________
  ক

  There may be a discontinuity in torque slip characteristics

  খ

  A high starting torque will be available

  গ

  The machine performs better

  ঘ

  The machine may fail to start
• The slope of the V-I curve is 7°. Calculate the value of resistance. Assume the relationship between voltage and current is a straight line.
  ক

  .122 Ω

  খ

  .360 Ω

  গ

  .377 Ω

  ঘ

  .578 Ω
• In a synchronous machine, the phase sequence can be reversed by reversing the _________
  ক

  Rotor direction

  খ

  Field polarities

  গ

  Armature terminal

  ঘ

  Rotor direction and armature terminal
• The hunting phenomenon in a synchronous motor is also referred to as _________
  ক

  Surging

  খ

  Phase swinging

  গ

  Cogging

  ঘ

  Surging and phase swinging
• The leakage flux paths are ________ on the angular position of the rotor.
  ক

  Dependent

  খ

  Proportional

  গ

  Independent

  ঘ

  Dependent and independent
• Calculate the phase angle of the sinusoidal waveform z(t)=8cos(45t+2π÷15).
  ক

  2π÷39

  খ

  2π÷15

  গ

  π÷4

  ঘ

  2π÷44
• A 4-pole, 3-phase, 60 Hz induction motor is operating at a speed of 1500 rpm. The frequency of the rotor current of the motor in Hz is __________
  ক

  5

  খ

  4

  গ

  2

  ঘ

  7
• The direct axis is taken along ________
  ক

  Inter-polar axis

  খ

  Rotor pole axis

  গ

  In between inter polar and rotor axis

  ঘ

  Parallel to interpolar axis
• Calculate the active power in a 788 ω resistor with 178 A current flowing through it.
  ক

  24.96 MW

  খ

  24.44 MW

  গ

  24.12 MW

  ঘ

  26.18 MW
• Calculate the active power in a 487 H inductor.
  ক

  2482 W

  খ

  1545 W

  গ

  4565 W

  ঘ

  0 W
• A 3-phase induction motor runs at almost 1000 rpm at no load and 950 rpm at full load when supplied with power from a 50 Hz, 3-phase supply. What is the corresponding speed of the rotor field with respect to the rotor?
  ক

  30 revolution per minute

  খ

  40 revolution per minute

  গ

  60 revolution per minute

  ঘ

  50 revolution per minute
• In an induction motor, when the number of stator slots is equal to an integral number of rotor slots _________
  ক

  There may be a discontinuity in torque slip characteristics

  খ

  A high starting torque will be available

  গ

  The maximum torque will be high

  ঘ

  The machine may fail to start
• The slope of the V-I curve is 5°. Calculate the value of resistance. Assume the relationship between voltage and current is a straight line.
  ক

  .3254 Ω

  খ

  .3608 Ω

  গ

  .3543 Ω

  ঘ

  .3443 Ω
• A 50 Hz, 4poles, a single phase induction motor is rotating in the clockwise direction at a speed of 1425 rpm. The slip of motor in the direction of rotation & opposite direction of the motor will be respectively.
  ক

  0.05, 0.95

  খ

  0.04, 1.96

  গ

  0.05, 1.95

  ঘ

  0.05, 0.02
• Calculate the moment of inertia of the thin spherical shell having a mass of 73 kg and diameter of 36 cm.
  ক

  1.56 kgm2

  খ

  1.47 kgm2

  গ

  1.38 kgm2

  ঘ

  1.48 kgm2
• Calculate the moment of inertia of the disc having a mass of 54 kg and diameter of 91 cm.
  ক

  5.512 kgm2

  খ

  5.589 kgm2

  গ

  5.487 kgm2

  ঘ

  5.018 kgm2
• Calculate the phase angle of the sinusoidal waveform z(t)=78sin(456πt+2π÷78).
  ক

  π÷39

  খ

  2π÷5

  গ

  π÷74

  ঘ

  2π÷4
• An 8-pole, 3-phase, 50 Hz induction motor is operating at a speed of 720 rpm. The frequency of the rotor current of the motor in Hz is __________
  ক

  2

  খ

  4

  গ

  3

  ঘ

  1
• A three-phase slip ring induction motor is fed from the rotor side with the stator winding short-circuited. The frequency of the current flowing in the short-circuited stator is ____________
  ক

  Slip frequency

  খ

  Supply frequency

  গ

  The frequency corresponding to rotor speed

  ঘ

  Zero
• Calculate the active power in a 17 ω resistor with 18 A current flowing through it.
  ক

  5508 W

  খ

  5104 W

  গ

  5554 W

  ঘ

  5558 W
• Calculate the active power in a 181 H inductor.
  ক

  2448 W

  খ

  1789 W

  গ

  4879 W

  ঘ

  0 W
• Calculate the active power in a 457 F capacitor.
  ক

  715 W

  খ

  565 W

  গ

  545 W

  ঘ

  0 W
• Calculate the active power in a 7481 H inductor.
  ক

  1562 W

  খ

  4651 W

  গ

  0 W

  ঘ

  4654 W
• The slope of the V-I curve is 27°. Calculate the value of resistance. Assume the relationship between voltage and current is a straight line.
  ক

  .384 Ω

  খ

  .509 Ω

  গ

  .354 Ω

  ঘ

  .343 Ω
• Calculate the value of the frequency if the capacitive reactance is 13 Ω and the value of the capacitor is 71 F.
  ক

  .0001725 Hz

  খ

  .0001825 Hz

  গ

  .0001975 Hz

  ঘ

  .0001679 Hz
• Calculate the shaft power developed by a motor using the given data: Eb = 404V and I = 25 A. Assume frictional losses are 444 W and windage losses are 777 W.
  ক

  8879 W

  খ

  2177 W

  গ

  8911 W

  ঘ

  8897 W
• Calculate the moment of inertia of the rod about its center having a mass of 11 kg and length of 29 cm.
  ক

  .091 kgm2

  খ

  .072 kgm2

  গ

  .076 kgm2

  ঘ

  .077 kgm2