Alternate Operation
Dual Battery
Option
The alternate power sources for standby power are the main battery and auxiliary battery.
With the standby power switch in the AUTO position, the loss of all engine or APU electrical
power causes the batteries to power the standby loads, both in the air and on the ground.
The AC standby bus is powered from the batteries via the static inverter. The DC standby
bus, battery bus, hot battery bus, and switched hot battery bus are powered directly from
the batteries.
The standby power switch provides for automatic or manual control of power to
the standby buses.
In the AUTO position, automatic switching from normal to alternate power occurs
if power from either AC transfer bus 1 or DC bus 1 is lost. Positioning the switch to BAT
overrides automatic switching and places the AC standby bus, DC standby bus, and battery
bus on battery power. The battery switch may be ON or OFF. If the battery switch is OFF,
the switched hot battery bus is not powered
.
Positioning the standby power switch to OFF de–energizes both the AC standby
bus and the DC standby bus and illuminates the STANDBY PWR OFF light.
Static Inverter
The static inverter converts 24 volt DC power from the battery to 115V AC power
to supply the AC standby bus during the loss of normal electrical power. The
power supply to the inverter is controlled by the standby power switch and the
battery switch on the overhead panel.
