| 1. | In a D.C. generator. If p be the number of poles and N be the r.p.m, of rotor, then the frequency of magnetic reversals will be ? | |
|
Np/2
|
||
|
Np/60
|
||
|
Np/120
|
||
|
Np/3000
|
||
View Answer
Discuss in Forum
Report Question| 2. | Which of the following generating machine will offer constant voltage on all loads ? | |
|
Self-excited generator
|
||
|
Separately excited generator
|
||
|
Level compounded generator
|
||
|
All of the above
|
||
| 3. | The essential condition for parallel operation of two D.C. generators is that they have ? | |
|
same kW rating
|
||
|
the same operation r.p.m.
|
||
|
the same drooping voltage characteristics
|
||
|
same percentage regulation
|
||
| 4. | A simple method of increasing the voltage of a D.C. generator is ? | |
|
to increase the length of the armature
|
||
|
to decrease the length of the armature
|
||
|
to increase the speed of rotation
|
||
|
to decrease the speed of rotation
|
||
| 5. | Which of the following statements is incorrect in D.C. shunt generators about hysteresis loss ? | |
|
It is independent of lamination thickness
|
||
|
It can be minimize by laminating the armature
|
||
|
It depends upon the supply frequency
|
||
|
None of the above
|
||
| 6. | A series generator can self-excite ? | |
|
only if the load current is zero
|
||
|
only if the load current is not zero
|
||
|
irrespective of the value of load current
|
||
|
none of the above
|
||
| 7. | A sinusoidal voltage of 5 Hz is applied to the field of a shunt generator. The armature voltage wave ? | |
|
will be zero
|
||
|
will be of 5 Hz
|
||
|
will be of 5 x N Hz
|
||
|
will be of N/5 Hz
|
||
| 8. | A 220 V D.C. generator is run at full speed without any excitation .The open circuit voltage will be ? | |
|
zero
|
||
|
about 2 V
|
||
|
about 50 V
|
||
|
220 V
|
||
| 9. | Which of the following generator will have negligible terminal voltage while running on no-load ? | |
|
Series generator
|
||
|
Shunt generator
|
||
|
Compound generator
|
||
|
Separately excited generator
|
||
| 10. | To achieve sparkless commutation brushes of a D.O. generator are rocked ahead so as to bring them ? | |
|
just ahead of magnetic neutral axis
|
||
|
in magnetic neutral axis
|
||
|
just behind the magnetic neutral axis
|
||
|
none
|
||