1. Lamination’s core is usually made up of
(A) Cast iron
(B) Carbon
(C) Silicon Steel
(D) Stainless Steel
Answer: C
2. Which of the following is the thickness of the DC machine
Lamination’s?
(A) 0.005 mm
(B) 0.05 mm
(C) 0.5 mm
(D) 5 mm
Answer: C
3. Bearings used to support the rotor shaft are usually
(A) Ball bearings
(B) Bushing Bearings
(C) magnetic bearing
(D) needle bearings
Answer: A
4. The armature of the DC generator is laminated
(A) reduce the heat
(B) provide the heat
(C) insulate the core
(D) reduce eddy current loss
Answer: D
5. Resistance to armature winding depends
(A) conductor length
(B) Cross-sectional area of conductor
(C) Number of conductors
(D. ALL OF THE ABOVE
Answer: D
6. The field coils of the DC generator are usually made
(A) Asbestos
(B) copper
(C) Cast iron
(D) Carbon
Answer: B
7. A four-pole In the DC machine
(A) All four poles are north poles
(B) Alternate poles are north and south
(C) All four poles are south poles
(D) Two north poles follow two south poles
Answer: B
8. The commutator segments are connected to the armature
conductor
(A) copper lugs
(B) resistance wires
(C) Insulation Pad
(D) brazing
Answer: A
9. In a switchboard
(A) copper is harder than mica
(B) Asbestos and copper are equally hard
(C) Asbestos is harder than copper
(D) None of the above
Answer: C
10. Pole shoes in D.C generators are fastened by pole cores.
(A) rivets
(B) counter sunk screws
(C) brazing
(D) welding
Answer: B
11. A differently stimulated generator than a self-excited
generator
(A) is responsible for better voltage control
(B) is more stable
(C) Free current of load current is
(D) All of the above are characteristics
Answer: D
12. Inspired EMF According to Fleming's right-hand rule to
find the direction of, when the inspired E.M.F. If the middle finger points in
the direction of, the index finger will point in the back.
(A) conductor speed
(B) force lines
(C) either of the above
(D) None of the above
Answer: B
13. D.C. Iron losses in the machine are independent of whose
change
(A) speed
(B) weight
(C) voltage
(D) speed and voltage
Answer: B
14. Fleming's right-hand rule regarding the direction of the
induced e.m.f is co-related.
(A) Magnetic current, direction of current flow and
resultant force
(B) Magnetic flow, direction of motion and EMF Moved towards
(C) Magnetic field strength, induced voltage and current
(D) magnetic flux, direction of force and direction of
motion of conductor
Answer: B
15. Fleming's right-hand rule and inspired e.m.f. When
applying in the direction of, the thumb points
(A) Inspired EMF direction of
(B) direction of flow
(C) If the EMF If the facade indicates the direction of
motion of the Conductor.
(D) The direction of motion of the conductor, if the index
finger points to the flow
Answer: D
16. In D.C generators, rapid brush wear may be the cause
(A) severe sparking
(B) rough commutator surface
(C) incomplete contact
(D) any of the above
Answer: D
17. The number of brushes in lap winding is always
(A) double the number of poles
(B) same as number of poles
(C) Half the number of poles
(D) two
Answer: B
18. A D.C. For winding when the number of poles and the
number of armature conductors are fixed, which winding is the highest e.m.f.
The
(A) lap winding
(B) Wave winding
(C) Both of (A) and (B) above
(D) depends on other features of the design
Answer: B
19. Copper brush is used in D.C machine
(A) where low voltage and high currents are involved
(B) where high voltage and small currents are involved
(C) In both the above cases
(D) None of the above cases
Answer: A
20. In the case of DC machines, mechanical losses are the
primary function.
(A) current
(B) voltage
(C) speed
(D) None of the above
Answer: C