Practice Test: Question Set - 11
1. The bearings used to support the rotor shafts are generally
- (A) Ball bearings
- (B) Bush bearings
- (C) Magnetic bearings
- (D) Needle bearings
2. The material for commutator brushes is generally
- (A) Mica
- (B) Copper
- (C) Cast iron
- (D) Carbon
3. Which of the following components of a D.C, generator plays vital role for providing direct current of a D.C. generator?
- (A) Dummy coils
- (B) Commutator
- (C) Eye bolt
- (D) Equalizer rings
4. The armature core of a D.C. generator is usually made of
- (A) Silicon steel
- (B) Copper
- (C) Nonferrous material
- (D) Cast-iron
5. Permeance is the reciprocal of
- (A) Flux density
- (B) Reluctance
- (C) Ampere turns
- (D) Resistance
6. A shunt generator running at 1000 r.p.m. has generated e.m.f. as 200 V. If the speed increases to 1200 r.p.m., the generated e.m.f. will be nearly
- (A) 150 V
- (B) 175 V
- (C) 240 V
- (D) 290 V
7. A D.C. generator can be considered as
- (A) Rectifier
- (B) Prime mover
- (C) Rotating amplifier
- (D) Power pump
8. The terminal voltage of a D.C. shunt generator drops on load because of all of the following reasons except
- (A) Armature reaction
- (B) Armature resistance drop
- (C) Field weakening due to armature reaction and
armature
- (D) Commutation
9. Which of the following generating machine will offer constant voltage on all loads?
- (A) Self-excited generator
- (B) Separately excited generator
- (C) Level compounded generator
- (D) All of the above
10. If B is the flux density, I the length of conductor and v the velocity of conductor, then induced e.m.f. is given by
- (A) Blv
- (B) Blv2
- (C) Bl2v
- (D) Bl2v2