A star connected 400 V, 50 Hz, 4 pole synchronous machine gave the following open circuit and short circuit test results:
Open circuit test: V_OC = 400 V (rms, line–to–line) at field current, I_f = 2.3 A
Short circuit test: I_SC = 10 A(rms, phase) at field current, I_f =1.5 A
The value of per phase synchronous impedance in Ω at rated voltage is __________.

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