A 20-pole alternator is having $180$ identical stator slots with $6$ conductors in each slot. All the coils of a phase are in series. If the coils are connected to realize single-phase winding, the generated voltage is $V_1$. If the coils are reconnected to realize three-phase star-connected winding, the generated phase voltage is $V_2$. Assuming full pitch, single-layer winding, the ratio $V_1$/$V_2$ is
1. $\frac{1}{\sqrt{3}}$
2. $\frac{1}{2}$
3. $\sqrt{3}$
4. $2$