a. AC Power Warning Lights.
the cable. This will isolate the faulted cable from power
input and will also terminate power crossfeed between
the two generating systems. Generator paralleling and
indicate an inverter failure.
balanced lead sharing between the two units is lost.
Both generators will remain in operation and all DC
b. Inverter Control Switch.
loads will continue to receive power. Each generator will
toggle switch on the left subpanel controls the selection
supply power only to the distribution buses and other
of aircraft inverter source. The switch is placarded
loads which connect to its respective generator bus. In
AIRCRAFT INVERTER, 1, OFF, and 2, (fig.
this circumstance, battery power will be applied only to
Neither inverter is a preferred unit, allowing the pilot free
the right generator bus. The shorted tie-cable will be
choice to select either unit. If an inverter fails in service,
indicated to the pilot only by divergent readings on the
power may be restored by selecting the alternate unit.
two volt-loadmeters: which will display the unbalanced
The aircraft inverter switch placarded AIRCRAFT
loads due to loss of paralleling. To restore connection of
INVERTER 1, OFF, and 2 provides a choice between
the bus hie-able to the generator buses, and recouple
two 2500 volt-ampere units for single-phase power.
the two generating systems, cycle the GND FAULT
circuit breaker on the copilot's circuit breaker panel (fig.
If the fault has been cleared, bus-tie will
restored. If a fault persists, the ground fault system will
maintain isolation of the tie-cable from the power input,
When inverters are switched, the
both generators will continue to operate, all DC loads will
magnetic compass will be affected.
be supplied, and only paralleling and power crossfeed
will be lost.
c. Inverter Control Circuit Breakers .
control relay circuits are protected by two 1-ampere
2-72. Bus Overload Protection System.
circuit breakers placarded INVERTER NO 1 and NO 2
CONTROL, RELAYS, located on the copilot's circuit
2-71. Ground Fault Protection System.
Do not reset the GND FAULT circuit
a. A ground fault detection and isolation system is
breaker more than one time. If it trips
integrated with the output cable from each generator to
after a reset no attempt should be
the respective generator bus, and with the tie-cable
made to reset the affected generator
which links the two generator buses together. A short in
using the GEN 1 switch.
either generator-to-generator-bus cable will cause the
ground fault system to open the respective line contactor
relay connecting the cable to the generator bus, and to
A bus overload and protection system is integrated
stop power production from the affected generator. Both
with the respective generator buses and also with the
the pilot's and copilot's MASTER WARNING lights will
battery-generator bus. A temperature-actuated sensor
stare to flash, and the L GEN OUT or R GEN OUT
detects the passage of excessive current through any of
the buses designated, and will isolate the affected bus
restore a generator to service, move the respective GEN
from current input and from connection with the rest of
switch to RESET position, then back to ON. If the
the system. Loss of the left generator bus is indicated
ground fault has cleared, the generator will be operative,
of the L, GEN OUT annunciator light, the GND FAULT
not reset, all aircraft DC loads will be supplied from the
circuit breaker trapped, and by a no load reading on the
remaining generator and the aircraft battery.
left volt-loadmeter. In this case, all aircraft DC loads are
supplied by the fight generator, except for those loads
b. A short in the wiring which links the two
which only receive power from the left generator. To
generator buses together will cause the ground fault
restore operation of the left generator and reconnect it to
system to open the line contactor relay at each end of
the respective generator bus, reset the GND FAULT
circuit breaker, then
Change 5 2-63