TRANSFORMER RECTIFIERS 1 AND 2 (TR 1 ANDTR 2)This topic presents TR1 and TR2 description and operation.TRANSFORMER RECTIFIER 1TR1 converts the 115 VAC power from AC BUS 1 into 28 VDC. Themonitoring card is supplied by the internal 28 VDC and from the bus401PP as a back-up supply. The 28 VDC output is connected to DCBUS 1 via contactor 5PU1.TRANSFORMER RECTIFIER 2TR2 converts the 115 VAC power into 28 VDC from AC BUS 2 viathe contactor 2PU, or on ground, with only EXTernal PoWeR Aconnected and the MAINTenance bus switch in ON position viacontactor 6XX.The monitoring card is supplied by the internal 28 VDC and from bus101P as a back-up supply. If TR1 is not operating (5PU1 open), themonitoring card of TR2 is supplied from bus 403PP.The 28 VDC output is connected to the DC BUS 2 and to the DCSERVICE BUS respectively via contactor 5PU2 and 1PN. The 28VDC output can also be connected to the DC SERVICE BUS viacontactor 1PX, only on ground with EXT PWR A connected and theMAINT bus switch in ON position.INTERFACESBoth main TR1 and TR2 interface with following systems:- System Data Acquisition Concentrators (SDACs) for ECAM warningand indications,- Electrical Contactor Management Units (ECMUs) for control ofcontactors 1PC1 (CNTOR - 28VDC BUS 1 / DC BAT BUS SPLY)and 1PC2 (CNTOR - 28VDC BUS 2 / DC BAT BUS SPLY ) forautomatic transfer and short circuit protection,