Correct Answer - Option 2 : 3000 rpm
Concept:
Synchronous speed of synchronous machine can be calculated as
\({N_s} = \frac{{120f}}{P}\)
Where,
f = Supply frequency in Hz
P = Number of poles
Ns = Synchronous speed in rpm
Calculation:
Given, f = 50 Hz
To get the maximum speed, the poles must be minimum.
Poles, P = 2
∴ \( {N_s} = \frac{{120\; \times\; 50}}{{2}}\)
NS = 3000 rpm