Related Topics

  Multiple Choice Question (MCQ) of D.C. Machines page-10  Multiple Choice Question (MCQ) of D.C. Machines page-9  Multiple Choice Question (MCQ) of D.C. Machines page-8  Multiple Choice Question (MCQ) of D.C. Machines page-7  Multiple Choice Question (MCQ) of D.C. Machines page-6  Multiple Choice Question (MCQ) of D.C. Machines page-5  Multiple Choice Question (MCQ) of D.C. Machines page-4  Multiple Choice Question (MCQ) of D.C. Machines page-3  Multiple Choice Question (MCQ) of D.C. Machines page-2  Multiple Choice Question (MCQ) of D.C. Machines page-1  MCQ of D.C motor page-4  MCQ of D.C motor page-3  MCQ of D.C motor page-2  MCQ of D.C motor page-1

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-Distribution

Multiple Choice Question (MCQ) of D.C. Machines page-2

11. The back emf of a dc motor

a) Adds to the supply voltage
b) Regulates its armature voltage
c) Helps in energy conversion
d) Usually exceeds the supply voltage

Ans: (c)

12. In dc motor, the rotor is

a) Welded to the shaft
b) Keyed to the shaft
c) Soldered to the shaft
d) Both to the shaft

Ans: (b)

13. In a dc motor, pole shoes are fixed to the magnet core by

a) Set of screws
b) Key
c) Soldering
d) Welding

Ans: (a)

14. In a dc motor, the ratio of back emf to supply emf is an indication of its

a) Efficiency
b) Speed regulation
c) Starting torque
d) Running torque

Ans: (a)

15. The armature of a dc motor is laminated

a) To reduce hysteresis loss
b) To reduce eddy current loss
c) To reduce the cost of core
d) To reduce the mass of the armature

Ans: (b)

16.The value of diverter resistance for a series dc motor is of the order of

a) 0.1Ω
b) 2Ω
c) 20Ω
d) 400Ω

Ans: (a)

17. The mechanical power developed by the armature of a dc motor is equal to

a) power input mainus copper loss
b) armature current multiplied by back emf
c) armature current multiplied by supply emf
d) power input minus mechanical loss

Ans: (b)

18. As the load on a dc shunt motor is increased, its speed

a) Increases proportionately
b) Remains constant
c) Increases slightly
d) Reduces slightly

Ans: (d)

19. A large series motor is never started without some load on it, otherwise

a) It draws very current
b) It develops excessive speed and get damaged
c) There results heavy sparking at the brushes
d) Circuit gets open circuited

Ans: (b)

20. When load is removed, which of the following dc motors will run at excessively high speed?

a) Shunt motor
b) Series motor
c) Cumulative compound motor
d) Differential compound motor

Ans: (b)

<< previous Next >>

Related topics :



Recent Post

Multiple Choice Question (MCQ) of Electronics page-17:
241. Which of the following statement is true? a) The saturation voltage VCF of silicon transistor is more than germanium transistor.
b) The saturation voltage VCE for germanium transistor is more than silicon transistor.
c) The saturation voltage VCE for silicon transistor is same as that for germanium.
d) The saturation voltage VCE for silicon transistor is lower than germanium transistor.

Read more...

Multiple Choice Question (MCQ) of Electronics page-16:
226. Which of the following statement is correct? a) Inner electrons are always present in the semiconductor.
b) Bound electrons are always present in the semiconductor.
c) Free electrons are always present in the semiconductor.
d) Inner and bound electrons are always present in the semiconductor.

Read more...

Multiple Choice Question (MCQ) of Electronics page-15:
211. The materials whose electrical conductivity is usually less than 1 × 106 mho/m are a) Semiconductors
b) Conductors
c) Insulators
d) Alloys

Read more...

Multiple Choice Question (MCQ) of Electronics page-14:
196. In which of the following device the base resistors are not added in the package but added externally? a) UJT
b) CUJT
c) PUT
d) None of the above

Read more...

Multiple Choice Question (MCQ) of Electronics page-13:
181. The conduction in JEFT is always by the a) Majority carriers
b) Minority carriers
c) Holes
d) Electrons
e) Holes and electrons simultaneously

Read more...