Synchronising Of Alternators

Step 1: Calculate the rated line current.


Step 2: Determine phase voltage and phase current.
For star connection,


Step 3: Calculate voltage drops.


Step 4: Calculate generated emf per phase.
At unity power factor,




Step 5: Conclusion.
The generated emf per phase is

Step 1: Recall the emf equation of an alternator.
The generated emf of an alternator is given by

Step 2: Analyze the effect of number of poles.
The frequency of generated emf is related to speed and number of poles by

If the number of poles increases, the synchronous speed decreases proportionally for constant frequency operation.
Step 3: Conclusion.
Since frequency and flux per pole remain constant under rated conditions, the generated emf does not change with increase in number of poles.
% Final Answer