| Display Selector |
| Ground Power and Bus Switching Panel with associated APU Lights and Indicators |
BUS TRANSFER Switch
AUTO (guarded position) –
Bus Tie Breakers operate automatically to maintain power to the
AC Transfer Busses from any operating generator or external
power.
OFF –
isolates AC Transfer Bus 1 from AC Transfer Bus 2 if one IDG is
supplying power to both AC transfer busses.
Condition: GEN 2 is not on the bus and GEN 1 is powering both
Transfer Busses.
AUTO (guarded position) –
Bus Tie Breakers operate automatically to maintain power to the
AC Transfer Busses from any operating generator or external
power.
- The DC cross tie relay automatically provides normal or
isolated operation as required.
OFF –
isolates AC Transfer Bus 1 from AC Transfer Bus 2 if one IDG is
supplying power to both AC transfer busses.
- The DC cross tie relay opens to isolate DC bus 1 from DC
bus 2.
Condition: GEN 2 is not on the bus and GEN 1 is powering both
Transfer Busses.