Correct Answer - Option 1 : Reduces harmonics from armature emf
For obtaining smooth sinusoidal emf waveform, conductors are placed is several slots under a single pole in a winding. This type of winding is known as distributed winding.
Although distributed armature winding of alternator reduces emf but still it very useful due to the following reasons
1. It reduces harmonic emf and so waveform is improved.
2. It also diminishes the armature reaction.
3. Even distribution of conductors, helps for better cooling.
4. The core is fully utilized as the conductors are distributed over the slots on the armature periphery.
Short pitch winding:
- It improves the waveform of generated emf i.e. generated emf can be made to approximate a sine wave more easily and the distorting harmonics can be reduced or totally eliminated.
- The disadvantage of using short-pitch winding is that the total voltage around the coils is somewhat reduced. In order to compensate for this reduction in Generated EMF, more number of turns, and therefore more copper is required.