GATE Electrical Engineering (EE) 2014 Shift 1 Solved Paper

A star connected 400 V, 50Hz, 4 pole synchronous machine gave the following open circuit and short circuit test results:
Open circuit test: ${\mathit{V}}_{\mathit{O}\mathit{C}}=400\mathit{V}$ (rms, line – to – line) at field current ${\mathit{I}}_{\mathit{f}}=2.3\mathit{A}$
Short circuit test: ${\mathit{I}}_{\mathit{S}\mathit{C}}=10\mathit{A}$ (rms, phase) at field current ${\mathit{I}}_{\mathit{f}}=1.5\mathit{A}$
The value of per phase synchronous impedance in Ω at rated voltage is ____________