| 1. | In an alternator the voltage of field system is usually ? | |
|
more than 1000 V
|
||
|
between 400 V and 600 V
|
||
|
less than 200 V
|
||
|
none of the above
|
||
View Answer
Discuss in Forum
Report Question| 2. | The regulation of an alternator is likely to be negative in case of ? | |
|
lagging power factor of the load
|
||
|
leading power factor of the load
|
||
|
high speed alternators
|
||
|
low speed alternators
|
||
| 3. | Which fractional pitch will eliminate the seventh harmonic from the voltage waveform of an alternator ? | |
|
6/7
|
||
|
7/8
|
||
|
5/6
|
||
|
None of the above
|
||
| 4. | An alternator operating at lower voltage, for the same power rating, will be ? | |
|
more efficient
|
||
|
costlier
|
||
|
less noisy
|
||
|
larger in size
|
||
| 5. | For a 3-phase winding with 5 slots per pole per phase and with coil span of 12 slot pitch, the value of pitch factor is ? | |
|
0.851
|
||
|
0.951
|
||
|
0.98
|
||
|
1.05
|
||
| 6. | In huge alternators, the moving part is ? | |
|
brushes
|
||
|
poles
|
||
|
armature
|
||
|
none of the above
|
||
| 7. | An alternator driven by a Francis hydraulic turbine is a ...... alternator ? | |
|
low speed
|
||
|
medium speed
|
||
|
high speed
|
||
|
low or medium speed
|
||
| 8. | Alternator of a central power station will have ? | |
|
revolving field winding
|
||
|
revolving armature winding
|
||
|
either of the above
|
||
|
none of the above
|
||
| 9. | In an alternator short-circuit current is limited by ? | |
|
the saturated synchronous impedance
|
||
|
the unsaturated synchronous impedance
|
||
|
either of the above
|
||
|
none of the above
|
||
| 10. | 4 pole 1500 r.p.m. alternator will generate e.m.f, at ? | |
|
20 Hz
|
||
|
40 Hz
|
||
|
50 Hz
|
||
|
60 Hz
|
||