DC Generator mcq questions answers part2

Q1. If brushes of a DC generator are moved in order to bring these brushes in magnetic neutral axis, there will be
(A) demagnetization only
(B) cross magnetization as well as magnetization
(C) cross magnetization as well as demagnetizing
(D) cross magnetization only

Q2. For a DC generator when the number of poles and the number of armature conductors is fixed, then which winding will give the higher EMF ?
(A) Lap winding
(B) Wave winding
(C) Either A or B
(D) None of these

Q3. The armature of DC generator is laminated to
(A) reduce the bulk
(B) provide the bulk
(C) insulate the core
(D) reduce eddy current loss

Q4. An exciter for a turbo generator is a
(A) separately excited generator
(B) shunt generator
(C) series generator
(D) differentially compound generator

Q5. In a DC generator stray loss is the sum of
(A) total copper loss and mechanical loss
(B) armature copper loss and iron loss
(C) shunt field copper loss and mechanical loss
(D) iron loss and mechanical loss

Q6. Number of tapings for each equilizer ring is equal to
(A) number of pole pairs
(B) number of poles
(C) number of parallel paths
(D) number of commutator segments

Q7. Which of the following constitute short-circuit in the armature winding.
(A) Insulation failure between two commutator bars
(B) Insulation failure between two turns of a coil
(C) Two of more turns of the same coil getting grounded
(D) All of the above

Q8. A cumulatively compounded long shunt generator when operating as a motor would be
(A) cumulatively compounded long shunt
(B) differentially compounded long shunt
(C) cumulatively compounded short shunt
(D) differentially compounded short shunt

Q9. Armature coil is short circuited by brushes when it lies
(A) along neutral axis
(B) along field axis
(C) in any of the above positions
(D) in none of the above positions

Q10. In a DC generator the magnetic neutral axis coincides with the geometrical neutral axis, when
(A) there is no load on|he generator
(B) the generator runs on full load
(C) the generator runs on overload
(D) the generator runs on designed speed

Q11. In DC generators the polarity of the interpoles
(A) is the same as that of the main pole ahead
(B) is the same as that of the immediately preceding pole
(C) is opposite to that of the main pole ahead
(D) None of these

Q12. DC series generator is used
(A) to supply traction load
(B) to supply industrial load at constant voltage
(C) voltage at the toad end of the feeder
(D) for none of the above purpose

Q13. The armature core of a DC generator is usually made of
(A) silicon steel
(B) copper
(C) non-ferrous material
(D) cast-iron

Q14. Which of the following types of brush has least voltage?
(A) Graphite brushes
(B) Carbon brushes
(C) Metal graphite brushes
(D) None of the above

Q15. Which of the following components of a D.C, generator provides direct current of a DC generator?
(A) Dummy coils
(B) Commutator
(C) primary winding
(D) Equilizer rings

Q16. In the case of lap winding resultant pitch is
(A) product of front and back pitches
(B) division of front pitch by back pitch
(C) sum of front and back pitches
(D) difference of front and back pitches

Q17. The winding used in Welding generator
(A) lap winding
(B) wave winding
(C) delta winding
(D) duplex wave winding

Q18. Eddy currents are induced in the pole shoes of a DC machine due to
(A) oscillating magnetic field
(B) pulsating magnetic flux
(C) relative rotation between field and armature
(D) all of the above

Q19. Armature reaction of an unsaturated DC machine is
(A) cross-magnetizing
(B) de-magnetizing
(C) magnetizing
(D) none of above

Q20. The material for dc generator commutator brushes is generally
(A) mica
(B) copper
(C) cast iron
(D) carbon

Q21. In DC generators, the cause of rapid brush wear may be due to
(A) severe sparking
(B) rough commutator surface
(C) imperfect contact
(D) all of the above

Q22. The bearings used to support the rotor shafts of a dc generator are generally
(A) ball bearings
(B) bush bearings
(C) magnetic bearmgs
(D) needle bearings

Q23. In DC generators the pole shoes are fastened to the pole core by
(A) rivets
(B) counter sunk screws
(C) brazing
(D) commutator

Q24. The commutator segments are connected to the armature conductors of a dc generator by means of
(A) copper lugs
(B) resistance wires
(C) insulation pads
(D) brazing

Q25. The resistance of armature winding of a dc generator depends on
(A) length of conductor
(B) cross-sectional area of the conductor
(C) number of conductors
(D) all of the above