41. Harmonics in the emf generated in an alternator can be reduced by
- skewing the slots
- chamfering the salient pole tips
- using distributed winding
- all of the above
42. Skew of rotor bar eliminatess in
- the effect of space harmonics
- the entire effect of crawling
- magnetic noise
- vibration due to unequal force developed on rotor
43. The emf generated due to nth harmonic component of flux in an alternator will be _____ the fundamental emf in magnitude.
- less than
- more than
- equal to
- half
44. Distributed winding and short chording employed in ac machines will result in
- increase in emf and reduction in harmonics
- reduction in emf and increase in harmonics
- increase in both emf and harmonics
- reduction in both emf and harmonics
45. In a synchronous generator, a divided winding rotor is preferable to conventional winding rotor because of
- higher efficiency
- increased steady state stability limit
- higher short circuit ratio
- better damping
46. In a cylindrical rotor synchronous machine, the phasor addition of stator and rotor mmfs is possible because
- two mmfs are rotating in opposite directions
- two mmfs are rotating in same directions at different speeds
- two mmfs are stationary with respect to each other
- one mmf is stationary and the other mmf is rotating
47. Three phase alternators are invariably connected in star so as to
- reduce the size of stator conductors used
- increase the terminal voltage
- reduce magnetic losses
- all of the above
48. The stator winding of an alternator is normally connected in star to eliminate the _____ harmonic component of the voltage waveform.
- first
- third
- fifth
- seventh
49. If the dimensions of all parts of a synchronous generator and the number of field and armature turns are doubled, then the generated voltage will change by a factor of
- 1
- 2
- 4
- 8
50. EMF induced per phase in an alternator depends on
- frequency
- number of turns per phase
- pitch factor
- distribution factor
- all of the above