TM 11-6125-220-20
Section Il.
OPERATION
b. Operational Check. The following preflight
2-5. General
The inverter must be energized before use and deener-
checks should be made as an extension of the ground
gized after use; no other operation is required. The in-
tests in the applicable aircraft operator's condensed
verter contains no on/off switch. It is energized auto-
checklist. The checks should be performed in the order
given.
matically when the aircraft 28 vdc power is applied and
deenergized when the power is removed. No warmup
is required before use. The input and output power is
NOTE
routed through other circuits of the aircraft in which
Use an external power source for making func-
the inverter is installed. Refer to the applicable aircraft
tional checks to prevent drain on aircraft bat-
technical manual for the proper switching sequence for
teries. (Refer to applicable aircraft technical
operating the inverter.
manual.)
2-6.
S t a r t i n g and Stopping Operation
(1) Start the inverter. If the aircraft in which the
a. Starting. Turn on the necessary aircraft switches
inverter is installed is equipped with panel meters for in-
to apply the 28 vdc to energize the inverter. The motor
dicating the ac voltage and frequency, check the output
should start.
of the inverter on the meters. (Refer to applicable air-
craft technical manual.) If the inverter is performing
CAUTION
satisfactorily, the voltmeter should indicate between 109
After starting the inverter, check for smoke or
and 121 or 202 and 214 volts ac, and the frequency
any other sign of malfunction. If any malfunc
meter should indicate between 390 and 410 Hz. Vary the
tion is noted, immediately remove the 28 vdc
load from no load to full load by turning on the air-
power.
craft equipment that operates with the ac supplied by
the inverter. (Refer to the applicable aircraft technical
b. Stopping. Turn off the necessary aircraft
manual.) The voltage indicated on the voltmeter should
switches to remove the 28 vdc from the inverter.
not vary more than 1 volt, and the indicated frequency
variation should be less than 6 Hz.
2-7. Initial Operational Check
(2) If no ac panel meters are installed in the air-
a. General. The operational check (b below) sup-
craft, check to see that the inverter is running by listen-
plements the inspection procedures in the aircraft opera-
ing to the motor. Turn on any aircraft equipment that
tor's condensed checklist. The operator's inspection
operates from the ac supplied by the inverter and check
consists of checking serviceability by performing an
to see that the equipment is operating. (Refer to the ap-
operational check. The checks listed should be accom-
plicable aircraft technical manual.)
plished before a flight. The pilot or copilot should report
(3) Turn off the necessary aircraft switches to
any malfunction or failure noted during the flight, or
stop the inverter.
any discrepancy noted in the preflight check (TM 38-750).
2-7
