Two synchronous motors having subtransient reactances of 0.95 and 0.91 p.u., respectively, on a base of 480 V, 3 MVA are connected to a bus. This motor bus is connected by a line having a reactance of 27 mΩ to a bus of a power system. At the power system bus the short circuit MVA of the power system is 4.8 MVA for a nominal voltage of 480 V. When the voltage at the motor bus is 407 V, calculate the rms of fault current in kA when a symmetrical bolted three phase fault occurs at the motor terminals.