A 50 HZ alternator will run at the greatest possible speed if it is wound for ...... poles

A 50 HZ alternator will run at the greatest possible speed if it is wound for ...... poles

A. 8
B. 6
C. 4
D. 2

Explanatory answer:

Ns=120F/P

Alternators always runs at synchronous speed and which is inversely proportional to no.of poles.

so lesser the poles higher the speed and the minimum possible no. of poles is 2

for P=2,  Ns=3000 rpm
for P=4, Ns=1500 rpm
for P=6, Ns=1000 rpm
for P=8, Ns=750 rpm

The correct ans is P=2