TM 11-6625-680-14-2
FUNCTIONING OF EQUIPMENT
a. The tester is designed so that any inverter,
a. A live circuit supplies current to the
filament and cathode heaters of electronic tubes
whether single-phase or three-phase delta output,
may be plugged into it by means of a suitable
used in the control circuits of some inverters. The
live circuit supplies power to the inverter through
cable set. The dc voltage is fed into the input
the B and D posts of connector J101 terminal
section of the inverter to be tested and thereby
block (fig. FO-2).
activates the inverter to be tested.
b. Connection of the live circuit is made
b. The input voltage and current are monitored
automatically by the cable set assembly and is
by reading the D.C. VOLTS meter and the D.C.
connected to the power side of the special in-
AMPS meter. The output voltage, frequency, and
terlock circuit so that tubes may be heated before
current of the inverter under test are indicated by
the D.C. POWER switch is set to ON, thereby
the A.C. VOLTS meter, FREQUENCY meter,
protecting the inverter at all times.
and A.C. AMPS meter, respectively.
c. The live circuit is protected by a 5-ampere
4-2. Load Bank
cartridge-type fuse with circuit interruption
The load bank imposes a load on the inverter
displayed by a red indicator light.
being tested. Variable electrical load is imposed
on the inverter by routing current through the
Fuses protect all meters, except the D.C. AMPS
tester load bank, with variable LOAD CONTROL
meter. The D.C. AMPS meter circuit includes a
s e t t i n g s providing the limits. T h e L O A D
sensitive-type relay that provides circuit in-
CONTROL setting varies in terms of percentage
terruption for a current overload from 110 to 130
of the maximum output voltage. The value of the
percent. The excessive current activates the
output voltage, frequency, and current are then
sensitive relay, which opens the dc power input to
m o n i t o r e d on
the A.C.
V O L T S meter,
the tester and opens the interlock circuit.
FREQUENCY meter, and A.C. AMPS meter,
respectively.
