inverter under test and the tester. Verify the
three-phase inverter. Position NA/N is used for a
inverter requirements for maintaining current to
provide heat in control circuits.
c. Operating Procedure.
(3) After performing the procedures given in
a above, turn on the dc input power and) then set
Do not touch rear of cabinet during test
the D. C. POWER switch to ON. The 28V. ON
operation. Do not place any equipment on
indicator lamp will illuminate and the inverter
o r near rear of cabinet during test
under test will run.
operation. Failure to observe this warning
(4) After 3 to 4 minutes of inverter under
can result in severe burn to personnel or
test warmup, s e t t h e A . C . A M M E T E R
fire hazard to equipment.
R A N G E , VOLTS/AMPS, LOAD, and D. C.
AMMETER RANGE switches as stated in the
Before turning the D. C. POWER switch
inverter under test technical manual.
to ON, check to be sure the inverter does
not incorporate an internal power relay or
(5) Slowly apply the load by adjusting the
LOAD CONTROL for the value of alternating
tubes requiring an external live circuit. If
current as stated in the inverter under test
it does, refer to the applicable publication
manual. Observe the readings on the A. C.
and turn the D. C. POWER switch and
LIVE CIRCUIT switch to ON in order
VOLTS, and D. C. AMPS meters to determine
and follow instructions regarding warm-
results of the test.
d. Stopping Procedure.
(1) Connect the dc input power source (set
(1) After performing the tests given in the
for 28 volts and capable of providing 160 amperes
inverter under test manual, slowly adjust the
to the -- D. C. and +28V terminal posts. (Do not
LOAD CONTROL counterclockwise until the
turn on the dc input power at this time.)
LOAD CONTROL reaches 0.
(2) Set the D. C. POWER switch to OFF.
After the dc power source is connected to
(The 28V. ON indicator lamp goes off and the
the 28 vdc input terminals, bind the input
inverter under test stops running.)
dc terminals of the test set with electrical
(3) Turn off the dc input power source.
insulation tape (NSN 5970-00-296-1625),
(4) Disconnect the cable set assembly.
leaving no bare metal of the binding posts
(5) If the inverter does incorporate an in-
or conductor exposed. Failure to observe
ternal power relay or tubes requiring an external
this warning can result in severe burns to
live circuit, refer to the inverter under test manual
for turning off the D. C. POWER switch and the
(2) Select the cable set assembly as given in
LIVE CIRCUIT switch.
a above and connect the cable set assembly to the