D.c. Generators(Electrical Engineering ) Questions and Answers

Question 1. Two D.C. shunt generators, each with armature resistance of 0.02 ohm and field resistance of 50 ohm run in parallel and supply a total current of 1000 amperes to the load circuit. If their e.m.fs. are 270 V and 265 V, their bus bar voltage will be
  1.    270 V
  2.    267.5 V
  3.    265 V
  4.    257.4 V
Explanation:-
Answer: Option B. -> 267.5 V
Question 2. If brushes of a D.C. generator are moved in order to bring these brushes in magnetic neutral axis, there will be
  1.    Demagnetization only
  2.    Cross magnetization as well as magnetization
  3.    Cross-magnetization as well as demagnetizing
  4.    Cross magnetization only
Explanation:-
Answer: Option C. -> Cross-magnetization as well as demagnetizing
Question 3. A cumulatively compounded long shunt generator when operating as a motor would be
  1.    Cumulatively compounded long shunt
  2.    Differentially compounded long shunt
  3.    Cumulatively compounded short shunt
  4.    Differentially compounded short shunt
Explanation:-
Answer: Option B. -> Differentially compounded long shunt
Question 4. The field coils of D.C. generator are usually made of
  1.    Mica
  2.    Copper
  3.    Cast iron
  4.    Carbon
Explanation:-
Answer: Option B. -> Copper
Question 5. Which of the following generators will be preferred if they are required to be run in parallel?
  1.    Shunt generators
  2.    Series generators
  3.    Compound generators
  4.    None of the above
Explanation:-
Answer: Option A. -> Shunt generators
Question 6. In a D.C. generator
  1.    External resistance = internal characteristic armature reaction
  2.    Internal characteristic = magnetization characteristic ohmic drop
  3.    External characteristic = magnetization characteristic ohmic drop armature reaction
  4.    Magnetization characteristic = external characteristic
Explanation:-
Answer: Option C. -> External characteristic = magnetization characteristic ohmic drop armature reaction
Question 7. The terminal voltage of a series generator is 150 V when the load current is 5 A. If the load current is increased to 10 A, the terminal voltage will be
  1.    150 V
  2.    Less than 150 V
  3.    Greater than 150 V
  4.    None of the above
Explanation:-
Answer: Option C. -> Greater than 150 V
Question 8. Permeance is the reciprocal of
  1.    Flux density
  2.    Reluctance
  3.    Ampere turns
  4.    Resistance
Explanation:-
Answer: Option B. -> Reluctance
Question 9. The e.m.f. induced in the armature of a shunt generator is 600 V. The armature resistance is 0.1 ohm. If the armature current is 200 A, the terminal voltage will be
  1.    640 V
  2.    620 V
  3.    600 V
  4.    580 V
Explanation:-
Answer: Option D. -> 580 V
Question 10. Shunt generators are most suited for stable parallel operation because of their
  1.    rising voltage characteristics
  2.    identical voltage characteristics
  3.    drooping voltage characteristics
  4.    linear voltage characteristics
Explanation:-
Answer: Option C. -> drooping voltage characteristics
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