| 1. | In alternators the standard practice, now a days is to have ? | |
|
rotating field
|
||
|
rotating armature
|
||
|
either of the above
|
||
|
none of the above
|
||
View Answer
Discuss in Forum
Report Question| 2. | Three-phase alternators are invariably star-connected because ? | |
|
higher terminal voltage is obtained
|
||
|
less turns of wire are required
|
||
|
small conductors can be used
|
||
|
magnetic losses are the minimum
|
||
| 3. | Synchronous impedance method gives more regulation as compared to ampere turn method because ? | |
|
armature reaction is considered negligible
|
||
|
saturation effect is ignored in the synchronous impedance
|
||
|
saturation effect is taken into account in the synchronous impedance method
|
||
|
none
|
||
| 4. | The power drawn by the prime-mover of an alternator, under no-load conditions, goes to ? | |
|
meet copper losses both in armature and rotor windings
|
||
|
produce power in armature
|
||
|
meet no-load losses
|
||
|
produce e.m.f, in armature winding
|
||
| 5. | In order to reduce the harmonics in the e.m.f generated in an alternator ? | |
|
winding is well distributed
|
||
|
slots are skewed
|
||
|
salient pole tips are chamfered
|
||
|
all of the above
|
||
| 6. | In an alternator, the stator frame serves ? | |
|
to verticate the armature
|
||
|
to hold the armature stampings
|
||
|
to protect the whole machine
|
||
|
as a return path for the flux
|
||
| 7. | The distribution factor, in alternators, is defined as the ratio of e.m.fs. of ? | |
|
distributed winding to full pitch winding
|
||
|
concentrated winding to distributed winding
|
||
|
distributed winding to concentrated winding
|
||
|
full pitch winding to distributed winding
|
||
| 8. | An infinite bus bar has ? | |
|
constant frequency and constant voltage
|
||
|
constant frequency and variable voltage
|
||
|
variable frequency and variable voltage
|
||
|
infinite frequency and infinite voltage.
|
||
| 9. | The maximum current that can be supplied by an alternator depends on ? | |
|
exciter current
|
||
|
strength of the magnetic field
|
||
|
number of poles
|
||
|
speed of the exciter
|
||
| 10. | For the alternators operating in parallel, if the load shared by one of them is to be increased, its field excitation is ? | |
|
to be weakened keeping input torque same
|
||
|
to be strengthened keeping input torque same
|
||
|
to be kept constant but input torque should be increased
|
||
|
to be kept constant but input torque should be decreased
|
||