# Practice Test: Question Set - 04

1. Which of the following generators will be preferred if they are required to be run in parallel?
(A) Shunt generators
(B) Series generators
(C) Compound generators
(D) None of the above

2. When two D.C. generators are running in parallel an equalizer bar is used
(A) To increase the series flux
(B) To increase the generated e.m.f.
(C) To reduce the combined effect of armature reaction of both the machines
(D) So that the two identical machines will pass approximately equal currents to the load

3. Laminations of core are generally made of
(A) Case iron
(B) Carbon
(C) Silicon steel
(D) Stainless steel

4. Fleming's right-hand rule regarding direction of induced e.m.f., correlates
(A) Magnetic flux, direction of current flow and resultant force
(B) Magnetic flux, direction of motion and the direction of e.m.f. induced
(C) Magnetic field strength, induced voltage and current
(D) Magnetic flux, direction of force and direction of motion of conductor

5. In a four-pole D.C. machine
(A) All the four poles are north poles
(B) Alternate poles are north and south
(C) All the four poles are south poles
(D) Two north poles follow two south poles

6. In case of a 4 pole D.C. generator provided with a two layer lap winding with sixteen coils, the pole pitch will be
(A) 4
(B) 8
(C) 16
(D) 32

7. The demagnetizing component of armature reaction in a D.C. generator
(A) Reduces generator e.m.f.
(B) Increases armature speed
(C) Reduces interpoles flux density
(D) Results in sparking trouble

8. For the parallel operation of two or more D.C. compound generators, we should ensure that
(A) Voltage of the incoming generator should be same as that of bus bar
(B) Polarity of incoming generator should be same as that of bus bar
(C) All the series fields should be run in parallel by means of equalizer connection
(D) Series fields of all generators should be either on positive side or negative side of the armature

9. The e.m.f. generated in a D.C. generator is directly proportional to
(A) Flux/pole
(B) Speed of armature
(C) Number of poles
(D) All of the above

10. 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

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