In Flight - Bus Transfer switch OFF

IDG 2 has failed.

  • The BTBs open and power to Transfer Bus
    2 and its associated busses is lost.

  • The right TRANSFER BUS OFF light
    illuminates.

  • TR 2 and TR 3 are unpowered and the
    Alternate Battery Relay closes powering the
    Battery Bus from the battery.
  • The AC Standby Bus is powered from its
    normal source, Transfer Bus 1.

  • The DC Standby Bus has lost backup from
    TR 2 and TR 3.

  • The Cross Bus Tie Relay opens and the
    automatic function is lost.
Moving the Bus Transfer switch to OFF in flight
is used only during some electrical abnormal
procedures.
Electrical System SGR
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