DC Generator mcq questions answers part1

Q1. In DC generators on no-load, the air gap flux distribution in space is
(A) flat topped
(B) sinusoidal
(C) triangular
(D) pulsating

Q2. In DC generators, current to the external circuit from armature is given through
(A) slip rings
(B) commutator
(C) solid connection
(D) None of these

Q3. In a DC generator the critical resistance refers to the resistance of
(A) armature windings
(B) field windings
(C) load
(D) brushes

Q4. In a four-pole DC machine
(A) all the four poles are north poles
(B) all the four poles are south poles
(C) alternate poles are north and south
(D) None of these

Q5. The number of brushes in a commutator depends on which of the following
(A) voltage
(B) amount of current to be collected
(C) type of winding
(D) speed of armature

Q6. In over compounded generator, full load terminal voltage is
(A) less than no load terminal voltage
(B) more than no load terminal voltage
(C) almost zero
(D) equal to no-load terminal voltage

Q7. In case of DC machines, mechanical losses are primary function of
(A) current
(B) voltage
(C) speed
(D) None of these

Q8. The purpose of providing dummy coils in a generator is
(A) to amplify voltage
(B) to provide mechanical balance for the rotor
(C) to reduce eddy current losses
(D) to enhance flux density

Q9. In DC generators, lap winding is suitable for
(A) high voltage, high current
(B) low voltage, high current
(C) high voltage, low current
(D) low voltage, low current

Q10. Flemings right-hand rule regarding direction of induced EMF, correlates
(A) magnetic flux, direction of current flow and resultant force
(B) magnetic field strength, induced voltage and current
(C) magnetic flux, direction of motion and the direction of EMF induced
(D) magnetic flux, direction of force and direction of motion of conductor

Q11. In DC machine winding, number of commutator segments is equal to
(A) number of armature coil sides
(B) number of armature coils
(C) number of armature conductors
(D) number of armature turns

Q12. Magnetic field in a DC generator is produced by
(A) permanent magnets
(B) electromagnets
(C) both of these
(D) None of these

Q13. In D.C. generators the pole shoes are fastened to the pole core by
(A) rivets
(B) counter sunk screws
(C) brazing
(D) welding

Q14. The EMF generated in a DC generator is directly proportional to
(A) speed of armature
(B) flux/pole
(C) number of poles
(D) all of the above

Q15. The number of brushes in lap winding is always
(A) double the number of poles
(B) half the number of poles
(C) same as the number of poles
(D) 2

Q16. Iron losses in a DC machine are independent of variations in
(A) load
(B) voltage
(C) speed
(D) All of these

Q17. Equilizer rings are required if the armature is
(A) wave wound
(B) lap wound
(C) delta wound
(D) duplex wound

Q18. DC generator field coils are usually made of which type of material
(A) mica
(B) carbon
(C) copper
(D) cast iron

Q19. DC generator generally preferred for charging automobile batteries is
(A) long shunt compound generator
(B) series generator
(C) shunt generator
(D) None of these

Q20. The demagnetizing component of armature reaction in a DC generator
(A) increases armature speed
(B) reduces generator EMF
(C) reduces inter-poles flux density
(D) None of these