Related Post

MCQ of D.C motor page-1MCQ of D.C motor page-2MCQ of D.C motor page-3MCQ of D.C motor page-4Multiple Choice Question (MCQ) of D.C. Machines page-1Multiple Choice Question (MCQ) of D.C. Machines page-2Multiple Choice Question (MCQ) of D.C. Machines page-3Multiple Choice Question (MCQ) of D.C. Machines page-4Multiple Choice Question (MCQ) of D.C. Machines page-5Multiple Choice Question (MCQ) of D.C. Machines page-6Multiple Choice Question (MCQ) of D.C. Machines page-7Multiple Choice Question (MCQ) of D.C. Machines page-8Multiple Choice Question (MCQ) of D.C. Machines page-9Multiple Choice Question (MCQ) of D.C. Machines page-10MCQ of D.C motor page-5MCQ of D.C motor page-6MCQ of D.C motor page-7MCQ of D.C motor page-8MCQ of D.C motor page-9MCQ of D.C motor page-10MCQ of D.C motor page-11MCQ of D.C motor page-12MCQ of D.C motor page-13MCQ of D.C motor page-14MCQ of D.C motor page-15MCQ of D.C motor page-16MCQ of D.C motor page-17MCQ of D.C motor page-18

Index

SymbolsTransformerRelayPower-SystemBasic-electricalACSR-ConductorCircuit-BreakerInterview-questions-of-Basic-ElectricityInterview-questions-of-transformerInsulatorCurrent-TransformerMCQMCQ-powersystemThermal-power-stationInterview-questions-of-Power-SystemPower-ElectronicsInterview-questions-of-Underground-CableInterview-questions-of-IlluminationIlluminationMCQ-of-ElectronicsMCQ-of-Basic-ElectricalMCQ-of-Transformers MCQ-of-D.C-motor MCQ-of-D.C-generatorsMCQ-Control-SystemMCQ-Measurementsmcq-of-Generation-power-systemMCQ-of-Induction-MotorMCQ-of-Transmission-DistributionMCQ-of-Electrical-MachinesMCQ-of-Alternator-and-Synchronous-MotorsMCQ-Electric-Power

MCQ of D.C motor page-11


≪ Previous Next ≫

61. A 230 V dc motor has an armature circuit resistance of 0.6 ohm. If the full load armature current is 30 A and the no-load armature current is 4 A, the change in back emf from no load to full load will be

A) 1.5 V
B) 15.6 V
C) 32.2 V
D) 64 V.

Ans : (B)

62. Which of the following motors is used for intermittent high torque load and for rolling mills?

A) DC shunt motor
B) DC series motor
C) DC differential compound wound motor
D) DC cumulative compound would motor.

Ans : (D)

63. A brake test is usually restricted to

A) small horse power motors
B) open frame type motors
C) variable speed motors
D) high speed motors.

Ans : (A)

64. A dc shunt motor has external resistance R1 in the field circuit and R2 in the armature circuit. The stating armature current for the motor will be minimum when

A) R1 is minimum and R2 is maximum
B) R1 is maximum and R2 is minimum
C) R1 and R2 both are minimum
D) R1 and R2 both are maximum.

Ans : (A)

65. In a dc motor, speed control by varying the armature circuit resistance provides a

A) variable power drive
B) variable torque drive
C) constant torque drive
D) constant power drive.

Ans : (C)

66. In Swinburne’s test the no-load power input to the armature supplies which of the following :

A) armature copper losses
B) friction and windage losses
C) iron losses in core
D) all of the above.

Ans : (D)

67. Which of the following is an assumption in the Swinburne’s test

A) mechanical losses vary directly as the rotor speed
B) decreases in flux due to increases in shunt resistance by heating is negligible
C) windage losses remain constant at a particular speed
D) all of the above.

Ans : (B)

68. A dc shunt motor draws an armature current of 40 A under normal rated conditions. If the field flux and the armature terminal voltage are reduced to half, then for constant power output, the armature current will be

A) 10 A
B) 20 A
C) 80 A
D) 160 A.

Ans : (C)

69. A differentially compounded dc motor runs at a full load speed of 480 rpm. Now if the series field of the motor is short-circuited, then full load speed will be

A) zero
B) less than 480 rpm
C) 480 rpm
D) more than 480 rpm.

Ans : (B)

70. Hopkinson’s test is conducted at

A) no load
B) low load
C) part load
D) full load.

Ans : (D)


≪ Previous Next ≫


Related topics :


Recent Post

Multiple Choice Question (MCQ) of Materials page-6:
51. The permeability and permittivity of a medium are
A) independent of each other
B) related by the atomic number
C) related by the Boltzmann’s constant
D) related by the velocity of electromagnetic waves.

Read more...

Multiple Choice Question (MCQ) of Materials page-5:
41. Bakelite is
A) highly inflammable
B) low resistance conductor
C) a semi-conductor
D) uncombustible.

Read more...

Multiple Choice Question (MCQ) of Materials page-4:
31. Which of the following pairs is commonly used in thermocouples?
A) Copper-constant
B) Aluminium-tin
C) Iron-steel
D) Silver-German silver.

Read more...