INTERFACESThe ESS TR interfaces with:- SDACs for ECAM warnings and indications,- CMC for TR reset.OPERATIONThe ESS TR is operative when it is supplied by AC BUS 1, or ACBUS 2 or EMER GEN. If all parameters are correct, the DC contactor3PE closes and connects the power to the DC ESS network.The DC ESS SHED BUS is lost in case of:- loss of both AC BUS 1, AC BUS 2 and if CSM/G is supplied by theRam Air Turbine (RAT),- A/C electrical network on battery only (emergency configuration).In case of ESS TR failure (not due to over-current), and if TR1 andTR2 are available, the contactor 4PC closes to allow the DC ESS BUSto be supplied from DC BUS 1 or DC BUS 2 via DC BAT BUS.